Anatomy: Autonomic innervation of the abdominal and pelvic organs.

Autonomic Nervous Supply (Ashwell)

• The sympathetic supply includes:

1. Greater splanchnic nerve (T5-9)
2. Lesser splanchnic nerve (T9-10)
3. Lowest (least) splanchnic nerve (T12)
4. Lumbar splanchnic nerves (L1-3)
5. Sacral splanchnic nerves
   • primarily pre-ggl SNS fibers that come off the chain, synapse in inf hypogastric plexus

• The parasympathetic supply includes:

1. Vagus nerve
2. Pelvic splanchnic nerve (S2-4)
   • only splanchnic n that carry PNS fibers
   • all others have SNS fibers
   • contribute to formation of pelvic (inf hypogastric) plexus, supply => desc colon, sigmoid colon, other viscera in pelvis and perineum

• These project to the paravertebral plexuses, which are situated anterior to the aorta and vertebral column.

Coeliac Plexus

• This contains the paired coeliac ganglia and is located at the level of the last thoracic and 1^st lumbar vertebra.
• It surrounds the root of the coeliac trunk and the superior mesenteric artery.

• The coeliac ganglia are paired structures, which lie between the suprarenal glands and the coeliac trunk origin.
• The lower part is partially detached and is sometimes referred to as the aorticorenal ganglion as it forms most of the renal plexus.

• Secondary plexuses derived from or connected to the coeliac are the phrenic, splenic, left gastric, intermesenteric (aortic), suprarenal, renal, gonadal, superior mesenteric and inferior mesenteric.

Phrenic Plexus

• This accompanies the inferior phrenic artery to the diaphragm and suprarenal gland.

Hepatic Plexus

• This is the largest coeliac derivative and receives filaments from both the right and left vagus as well as from the phrenic nerves.

• It accompanies the hepatic artery and the portal vein and their branches and also supplies the cystic plexus to the gallbladder.
• Branches may also supply the pylorus, greater curvature of stomach as well as the lower bile duct, pancreatic head and 1^st and 2^nd part of duodenum.

Left Gastric Plexus

• This goes to the lesser curvature of the stomach.

Splenic Plexus

• This is formed by branches of the coeliac plexus, left coeliac ganglion and the right vagus.
• It supplies the blood vessels and smooth muscles of the splenic capsule and trabeculae.

Suprarenal Plexus

• This supplies the medulla of the suprarenal gland.

Renal Plexus

• This is formed by fibres from the coeliac ganglion and plexus, aorticorenal ganglion, lowest thoracic splanchnic nerves, 1^st lumbar splanchnic nerve and the aortic plexus.

• It gives off the ureter and gonadal plexuses (ovarian or testicular).
• The ureteric plexus accompanies the ureter and the gonadal plexuses accompany the appropriate artery to the respective organs.

Superior Mesenteric Plexus

• This is a downward extension of the coeliac plexus.
• It accompanies the superior mesenteric artery to the pancreas, small intestine (duodenum, jejunum and ileum), and large intestine as far as the left trisection of the transverse colon.

Abdominal Aortic Plexus (intermesenteric)

• This supplies the IVC, and testicular plexuses as well as connecting the superior and inferior mesenteric plexuses.

Inferior Mesenteric Plexus

• This receives supply from the aortic plexus and 2^nd and 3^rd lumbar splanchnic nerves.
• It supplies the colon from the left trisection of the transverse colon to the rectum.

Superior Hypogastric Plexus

• This is situated anterior to the aortic bifurcation, L5 and the sacral promontory.
• This plexus is formed from branches of the aortic plexus, 3^rd and 4^th lumbar splanchnic nerves.

• It divides into the left and right hypogastric nerves, which descend to the 2 inferior hypogastric plexuses, which lie anterior to the sacrum.
  • lies in extraperitoneal CT lat to rectum
  • sends br to sigmoid, desc colon
• located retroperitoneally
• has preggl/post ggl SNS fibers, visc aff fibers + PNS fibers (few), which may run a recurrent course thru inf hypogastric plexus

Inferior Hypogastric Plexus

• This is formed from the pelvic splanchnic nerves (from the sacral plexus, S2-4) and also receives the sacral splanchnic nerves., and hypogastric n
• lies against post/lat pelvic wall
• lat to rectum, vagina, base of bladder
• contains pelvic ggl = where SNS, PNS preggl fibers synapse
• Several plexuses arise from the inferior hypogastric plexuses, including:

1. Middle rectal plexus
2. Vesical plexus
3. Prostatic plexus
4. Uterovaginal plexus
5. Deferential plexus

Histology: The cartilage tissue.

Embryology: Fetal membranes. Umbilical cord. Amniotic fluid. Fetal circulation.

Fetal Membranes

Around the beg of 2nd month, villi system in trophoblast layer consists mostly of sendary & tertiary villi

consists mostly of secondary/tertiary villi
As development continues – more primitive villi will grow as extensions of exisitng ones
some of the cytotrophoblast cells /CT  will disappear – leave just syncyticum, endothelium lining of capillaries as barrier b/w fetal and maternal circulations = syncytial knots

Villi system covers the entire span of chorion @ early stages of development
However, w/ time changes will occur on diff poles of the embryo
1. villi on embryonic pole will continue to grow creating = chorion frondosum –> fetal portion of placenta
2. villi on abembryonic pole will degenerate leaving a smooth side = chorion laeve

From maternal side, b/w 3 deciduas which are functional layers of endometrium
1. Decidua basalis – in contact w/ chorion frondosum, decidual cells w/ lipids, glycogen
2. Decidua capsularis – covering abembryonic pole, will later degenerate when embryo grows
3. Decidua parietalis – covering opp side of uterine wall, will fuse w/ amnion & chorion laeve

Once amnion/chorion laeve unite – they form amniochroionic membrane which destroys chorionic cavity

Amnion & Umbilical Cord

Umbilical Cord
@ 5th week, opening can be found connecting amnion & ectoderm = primitive umbilical ring
Contains:
a) Yolk sac stalk (= vitelline duct) along w/ vitelline vessels
b) Canal connecting intra/extra embryonic cavities
c) Connecting stalk: allantois, umbilical vessels (2 arteries, v)

Amniotic cavity will expand, eventually getting rid of chorionic cavity
this pushes vitelline duct & connecting stalk until they join = primitive umbilical cord
Contains:
Prox = allantois *urachus*, intestinal loops
Distal = vitelline duct, umbilical a/v

During growth of abdominal organs, abdominal cavity isn’t big enough for organs, so intestinal loops push into umbilical cords = umbilical herniation
Come out again @ end of 3rd month
vitelline vessels are obliterated

Only umbilical vessels, and Wharton’s jelly left inside – jelly has many PGs, and protects the a/v

Amniotic fluid

formed by amnioblasts (cells from epiblast that line amniotic cavity) & maternal blood
replaced every 3 hours – sterile because waste products are filtered out
Function:

• shock absorbance
• prevents adhesion of embryo to amnion
• allows fetal movement

@ fifth month, organ systems begins to function, fetus swallows the amniotic fluid, also produces urine into it (which is mostly water – as mentioned b4 placenta filiters it out)

Fetal Circulation

Anim = Fetal Circulation and Baby’s First Breath

Anim2 = The Wonders of Fetal Circulation

• Introduction

• Throughout the fetal stage of development, the maternal blood supplies the fetus with O₂ and nutrients and carries away its wastes.
  • These substances diffuse between the maternal and fetal blood through the placental membrane.
  • They are carried to and from the fetal body by the umbilical blood vessels.
• Adaptations of fetal blood and vascular system.
• The concentration of hemoglobin in fetal blood is about 50 % greater than in maternal blood.
• Fetal hemoglobin is slightly different chemically and has a greater affinity for O₂ than maternal hemoglobin.
  • At a particular oxygen partial pressure, fetal hemoglobin can carry 20-30% more O₂ than maternal hemoglobin.

• Fetal Circulation OH-98

• In the fetal circulatory system, the umbilical vein transports blood rich in O₂ and nutrients from the placenta to the fetal body.
  • The umbilical vein enters the body through the umbilical ring and travels along the anterior abdominal wall to the liver.
    • About 1/2 the blood it carries passes into the liver.
    • The other 1/2 of the blood enters a vessel called the ductus venosus which bypasses the liver.
  • The ductus venosus travels a short distance and joins the inferior vena cava.
    • There, the oxygenated blood from the placenta is mixed with the deoxygenated blood from the lower parts of the body.
    • This mixture continues through the vena cava to the right atrium.
  • In the adult heart, blood flows from the right atrium to the right ventricle then through the pulmonary arteries to the lungs.
    • In the fetus however, the lungs are nonfunctional and the blood largely bypasses them.
  • As the blood from the inferior vena cava enters the right atrium, a large proportion of it is shunted directly into the left atrium through an opening called the foramen ovale.
    • A small valve, septum primum is located on the left side of the atrial septum overlies the foramen ovale and helps prevent blood from moving in the reverse direction.
  • The rest of the fetal blood entering the right atrium, including a large proportion of the deoxygenated blood entering from the superior vena cava passes into the right ventricle and out through the pulmonary trunk.
    • Only a small volume of blood enters the pulmonary circuit, because the lungs are collapsed, and their blood vessels have a high resistance to flow.
      • Enough blood reaches the lung tissue to sustain them.
  • Most of the blood in the pulmonary trunk bypasses the lungs by entering a fetal vessel called the ductus arteriosus which connects the pulmonary trunk to the descending portion of the aortic arch.
    • As a result of this connection, the blood with a relatively low O₂ concentration which is returning to the heart through the superior vena cava, bypasses the lungs.
    • At the same time, the blood is prevented from entering the portion of the aorta that provides branches leading to the brain.
  • The more highly oxygenated blood that enters the left atrium through the foramen ovale is mixed with a small amount of deoxygenated blood returning from the pulmonary veins.
    • This mixture moves into the left ventricle and is pumped into the aorta.
      • Some of it reaches the myocardium through the coronary arteries and some reaches the brain through the carotid arteries.
  • The blood carried by the descending aorta is partially oxygenated and partially deoxygenated.
    • Some of it is carries into the branches of the aorta that lead to various parts of the lower regions of the body.
    • The rest passes into the umbilical arteries, which branch from the internal iliac arteries and lead to the placenta.
      • There the blood is reoxygenated.

• The Newborn

• The initial inflation of the lungs causes important changes in the circulatory system.
• Inflation of the lungs reduces the resistance to blood flow through the lungs resulting in increases blood flow from the pulmonary arteries.
  • Consequently, an increased amount of blood flows from the right atrium to the right ventricle and into the pulmonary arteries and less blood flows through the foramen ovale to the left atrium.
• In addition, an increased volume of blood returns from the lungs through the pulmonary veins to the left atrium, which increases the pressure in the left atrium.
  • The increased left atrial pressure and decreased right atrial pressure (due to pulmonary resistance) forces blood against the septum primum causing the foramen ovale to close.
  • This action functionally completes the separation of the heart into two pumps–right and left sides of the heart.

• The closed foramen ovale becomes the fossa ovalis.
  • The ductus arteriosis, which connects the pulmonary trunk to the systemic circulation, closes off within 1-2 days after birth.
    • Once closed, the ductus arteriosus is replaced by connective tissue and is known as the ligamentum arteriosum.

• If the ductus arteriosus does not completely close it is said to be patent.
  • This is a serious birth defect resulting in marked elevation in pulmonary pressure because blood flows from the left ventricle to the aorta, through the ductus arteriosus to the pulmonary arteries.
  • If not corrected, it can lead to irreversible degenerative changes in the.heart and lungs.
  • The fetal blood supply passes to the placenta through two (2) umbilical arteries from the internal iliac arteries and returns through an umbilical vein which passes through the liver, ductus venosus, and joins the inferior vena cava.
    • When the umbilical cord is cut, no more blood flows through the umbilical arteries and vein and they degenerate.

• The remnant of the umbilical vein becomes the round ligament of the liver and the ductus venosum becomes the ligamentum venosum.

Flash Cards:

Bones of Pelvis

Bones of Pelvis 2 - sciatic foramens

Blood Supply of Pelvis

Blood Supply 2

Nerve Supply of Penis

Autonomic Nerves of Pelvis

Anatomy: Bones, muscles and ligaments of the pelvis. The blood vessels and nerves of the pelvis.

Bones & Ligaments of Pelvis

Pelvis bony girdle
2 hip bones = ox coxae, = 3 bones fused together = ilium, ischium, pubis
sacrum
coccyx

Pelvic Diameters of female: important for birthing processes

• Conjugate diameters – b/w symphysis and sacral promontory = 11cm
• Tranverse diameters – mid point of brim on each side  = 13cm
• Oblique diameters – iliopubic eminence –> sacroiliac joint = 17.5cm
• To set axis correctly = ASIS +pubic tubercle in vertical line

Structures to show on pelvic girdle:

1. Pubic symphyis
2. Iliac crest
3. Ant sup iliac spine (attachment of inguinal lig, plus part of way to find McBurney’s pt)
4. Greater/Lesser sciatic forament
5. sacral promontory
6. ischio pubic rami
7. inf pubic rami
8. obturator foramen
9. acetabulum
10. ischial spine
11. ischial tuberosities

Pelvic Girdle

Divided by pelvic brim:
false pelvis above = b/w iliac wings
true pelvis below = b/w pelvic brim and outlet

Pelvic brim = pelvic inlet
Borders:

• post = sacral promontory, massa lata of sacrum
• lat/post =arcuate line of ilum
• lat/ant = iliopubic eminence, then pectinate line
• ant = pubic crest, pubic symphysis

Pelvic Outlet

• ant = inf border of pubic symphysis, arcuate ligament, inf pubic rami (making subpubic angle)
• lat = ischial tuberosities, sacrotuberous ligaments
• closed off by pelvic and urogenital diaphragms

M of wall of true pelvis: *Show these on speciment of dried pelvis:

• piriformis – triangular shaped m, can identify b/c the tendon will go to gr. trochanter of femur, and you will sciatic n emerge below it
• ob internus m – can identify b/c only n. running to obturator foramen on the inside of pelvic cavity, will wrap around and cover the obturator foramen
  
• pelvic diaphragm = coccygeus + levator ani m – point to muscles that attach to coccyx
• UG diaphragm = deep transverse perineal m, fascia *may not be able to show this*

Differences b/w Male & Female Pelvis

• Bones thinner, smaller, lighter in female
• Inlet heart shaped in male, oval in female - in male, sacral promontory juts into to lesser pelvis
• Outlet larger in female > male
• Pelvic cavity wider/shallower in female
• subpubic angle < 90 degrees in male, and obtuse in female (>90)
  • **Good one to tell difference, if asked if pelvis is male or female
  • If the subpubic angle is the distance as you making a peace sign with your fingers = male
  • if it is the same as the angle b/w you spreading your thumb/forefinger = female
• female sacrum shorter and wider than male
• obturator foramen is oval or triangular in female and round in male

Joints of Pelvis

1. Lumbosacral joint - b/w L5-sacrum, held by IV disk and supported by iliolumbar ligaments, iliolumbar a from int iliac a run next to this vertically
2. Sacroiliac joint – synovial joint of plane type b/w articular cartilage of sacrum and ilium
   • ant/post sacroiliac ligaments
   • interossesus ligaments
   • transmit weight of body from vertebral column to pelvic girdle
3. Sacrococcygeal joint – cartiliagenous joint b/w sacrum & coccyx
   • ant, post, lat sacrococygeus lig
4. Pubic symphysis – fibrocartiliginous joint b.w pubic bones in medial plane, anteriorally
   

Major Ligaments of Pelvis — good time to mention what goes thru gr/lsr sciatic foramen

1. Sacrospinous – from sacrum –> ischial spine
2. Sacrotuberous – from sacrum –> ischial tuberosities
3. ant/post sacroiliac ligaments
4. ant/post/lat sacrococcygeal lig
5. ant longitudial lig – runs down front of vert bodies
6. iliolumbar lig
7. supraspinous lig

Pelvic ligaments ant view

Greater Sciatic notch is split into 2 sciatic foramen via sacrospinous/ sacrotuberous ligament

Greater Sciatic foramen

• Piriformis
• sup/inf gluteal a/v/n
• sciatic n * show this*
• post femoral cut n
• int pudendal a/v
• pudendal n

NOTE – Piriformis m further separates the greater sciatic foramen into a supra/infrapiriformic hiatus.
The only structures that go thru suprapiriformic hiatus = sup gluteal a/v/n (Supra =superior)

Rest go thru infrapiriformic hiatus, as well as n to ob internus.

CLINICAL NOTE – Because of the emergence of these structures, anasthesia can only be given in the upper R quadrant of the gluteal region, so as not to paralyze any nerves, or harm blood supply

Lesser Sciatic Foramen

• Ob internus
• Int pudendal a/v
• pudendal n

Remember: the pudendal structures come out of the greater sciatic foramen–> then turn around the ischial spine –> back in thru lesser sciatic foramen –> to Alcock’s canal running in the fascia over obturator int m in ischioanal fossa

Blood Supply of Pelvis

A. Int Iliac a – @ bifurcation of common iliac a, in front of sacroiliac joint, crossed in front by ureter @ pelvic brim

Post Division: (3) = Iliolumbar a, Lat Sacral a, Sup Gluteal a
1. Iliolumbar a – sup/lat to iliac fossa, deep to psoas major, runs straight up, next to iliolumbar ligaments
- Iliac br => iliacus m, ilium
-Lumbar br => psoas major, quadratus lumborum

2. Lat sacral a – passes med, in front of sacral plexus, runs immediately to sacrum
- spinal br (goes thru ant sacral formina) => spinal meninges, roots of sacral n, musc/skin overlying the sacrum

3.Sup gluteal a – b/w lumbosacral trunk + 1st sacral n
-leaves pelvis thru gr sciatic foramen above piriformis m
=> m. of buttocks

Ant Division (8) = Inf gluteal a, int pudendal, umbilical a, obturator, inf vesical, med rectal, uterine
1.Inf gluteal a – b/w 1&2 or 3&4 sacral n
leaves pelvis thru gr sciatic foramen, infrapiriformic hiatus

2. Int pudendal a – leaves pelvis thru gr sciatic foramen, b/w piriformis & coccygeis  –> perineum via lesser sciatic foramen

3. Umbilical a- v. tortous a, runs along lat pelvic wall & along the side of bladder
a) Prox part –> sup vesicle a => sup bladder
a of ductus deferens => DD, seminal vesicle, lower ureter, bladder

b)Distal part –> becomes obliterated, & goes forward as medial umbilical ligament

4. Obturator a (can also come from inf epigastric a)
pass across femoral canal –> obturator foramen
-ant br => m of thigh
-post br => m of thigh
-acetabular br runs to acetabular notch –> head of femur via lig. capitum femoris

5.Inf vesical a (M, vaginal a in F) => prostate, fundus of bladder, DD, seminal vesicle, lower ureter

6.Vaginal a (F from uretine a/v or int iliac a)
numerous br => ant/post wall of vagina & makes logitudinal anatomosis  in med plane to make
ant/post azygos a of vagina

7.Middle rectal a – run med => musc layer of lower rectum & upper anal canal, prostate gland, ureter (seminal vesicles, vagina)

8.Uterine a (Deferential a in M) – from int iliac a or w/ vaginal or middle rectal a
run med in base of broad lig –> jxn of cervix & body of uterus & runs in front of /above ureter & near lat fornix of vagina
-sup br => body + fundus of uterus
-vaginal br => cervix + vagina

B. Median sacral a
unpaired a, arising from post aspect of abdominal aorta just before bifurcation
desc in front of sacrum => post rectum, end in coccygeal body as small vascular mass in front of tip of coccyx

C Sup rectal a - from inf mesenteric a

D. Ovarian a – one of paired visceral branches of ab aorta,
crosses prox end of ext internal a –> minor pelvis + reaches ovary thru suspensory lig of ovary

Nerve Supply to Pelvis
A. Sacral Plexus
formed by L4-5 ventral rami (lumbosacral trunk) + 1st 4 sacral ventral rami, lies on piriformis m in pelvis, below pelvis fascia

1.Sup gluteal n (L4-5) – leaves pelvis thru gr sciatic foramen, suprapiriformic hiatus
=> gluteus medius,minimus, tensor fascia lata

2.Inf gluteal n (L5-S2) - leaves pelvis thru gr. sciatic foramen => glut max m

3.Sciatic n (L4-S3) – largest n in body
a) Tibial n = post leg
b) Common fibular = ant/lat leg
- deep/sup fibular branches
composed of peroneal & tibial parts
leaves pelvis thru gr sciatic foramen, infrapiriformic hiatus
runs thigh in hollow b/w ischial tuberosity & gr. trochanter

4.N to ob internus m (L5-S2)
leaves pelvis thru gr sciatic foramen, infrapiriformic hiatus
perineum thru lesser sciatic foramen
=> ob internus, sup gemellus m

5. N to quadratus femoris (L5-S1)
leaves pelvis thru gr sciatic foramen, infrapiriformic hiatus
runs deep to gemellus m, ob internus, and ends in deep surface of quadratus femoris
=> quadratus femoris & inf gemellus m

6. Post femoral cut n (S1-S3)
leaves pelvis thru gr sciatic foramen, infrapiriformic hiatus
lie w. sciatic n and desc on back of knee
- inf cluneal n, perineal br

7. Pudendal n (S2-S4)
leaves pelvis thru gr sciatic foramen below piriformis –> perineum, thru lesser sciatic foramen => bulbospongiosus, ischiocavernosus, sphincter urethrae, deep/sup transverse perineal m

8. Br to pelvis

• n to piriformis (S1-2)
• n to levator ani + coccygeus m (S3-4)
• n to sphincter ani
• pelvic splanchnic n

*** Lumbosacral trunk connect sacral/lumbar plexus (L4-S4)

Histology: The bone tissue.

Embryology: Gastrulation, early differentiation of the intraembryonic mesoderm

Gastrulation

• makes the 3 defined germ layer of embryo = ectoderm, mesoderm, endoderm
• @ day 21 = called trilaminar germ disk
• indicated by primitive streak = epiblast cells
  • primtive groove, node, and pit
  • primitive node = cephalic end of streak, elevation around the primitive pit
• caudal to primitive streak – future anus = cloacal membrane – epiblast/hypoblast fused here
• epiblast = ectoderm + intraembryonic mesoderm + endoderm of trilaminar disk
• @ wk 2 – intraembryonic mesoderm begins to form organs
• @ wk 3 – extraembryonic mesoderm begins to form placenta

Differentiation to Intraembryonic Mesoderm

1. Paraxial mesoderm - right next to midline, become somites

• first 7 = pharyngeal arches
• 42-44 pairs of somites from rest of them –> eventually condense to 35 pairs
• each somite has 3 parts: sclerotome, myotome, dermatome
  • sclerotome = bones, ligaments
  • myotome = muscle
  • dermatome = skin

2. Intermediate Mesoderm – b/w paraxial and lateral mesoderm

• forms urogenital ridge –> kidney & gonads

3. Lateral Mesoderm

• intraembryonic coelem forms – splits lat mesoderm into 2 layers
  • somatic
  • visceral

4. Notochord - mesoderm in midline from primitive node –> prechordal plate

• stimulates ectoderm on top –> neuroectoderm –> neural plate
• stimulates formation of vertebral bodies & nucleus palposus

5. Cardiogenic region

• horseshoe shaped region of mesoderm  @ cranial end of embryonic disk
• is the future heart

Flash cards:

Perineum - Anatomy Topic Notecard - Right Click and select "View this Image" to see it larger

Anatomy Topic Notecard - Right Click and select "View this Image" to see it larger

Perineum 2 - Anatomy Topic Notecard - Right Click and select "View this Image" to see it larger

Anatomy of  the perineum.

Perineum
diamond shaped space w/ same boundaries as pelvic outlet
inf to pelvic diaphragm (& UG diaphragm)

NOTE – MALE = BLUE, FEMALE = PINK

Borders

• ant = pubic symphysis
• post = tip of coccyx
• ant/lat = ischiopubic ramus
• lat = ischial tuberosity
• post/lat = sacrotuberous lig

Layers of Perineum: (outside –> in)

1. Skin
2. subcutaneous adipose tissue
3. Superficial perineal fascia
4. Superficial perineal space
   • bulb/crura of penis/clitoris
   • sup transverse perineal  m
   • ischiocavernosus m
   • bulbospongiosusm
   • a/v/n
5. UG diaphagm
   • Inferior fascia of UG diaphragm = deep perineal fascia = perineal membrane
   • deep transverse perineal m (post) + sphincter urethra (ant)
   • superior fascia of UG diaphragm
6. Deep perineal space – ant continuation of ischio-anal fossa, has pudendal canal
7. Pelvic diaphragm
   • inferior fascia of levator ani m
   • levator ani m
   • superior fascia of levator ani m
8. Lesser pelvis

NOTE = Inf fascia of UG diaphragm is the SAME AS  deep perineal fascia is SAME AS = perineal membrane

Layers of Perineal Area Female

Perineal Layers Male

A line b/w the 2 ischial tuberosities, divides the perineum into 2 triangles
ant = Urogenital triangle
post = anal triangle

Urogenital Triangle
A. Superficial perineal space
b/w inf fascia of UG diaphragm & membranous layer of sup perineal fascia (Colles’)

Superficial Perineal Space

1. Colles fascia

• deep membranous layer of sup perineal fascia
• inf boundary of sup perineal fascia
• cont w. tunic dartos of scrotum, w/ sup fascia of pelvis & w/ Scarpa’s fascia of ant ab wall

2. Perineal Membrane

• inf fascia of UG diaphram & lies b/w it and ext genitalia
• perforated by urethra & attached  to post margin of UG diaphragm & ischiopubic rami
• thickened ant to form transverse lig of perineum, covers the inf pubic rami
• lies post to deep dorsal v of penis/clitoris

3. M of sup  perineal space

a) Ischiocavernosus m – ischial tuberosity –> ischiopubic rami –> corpus cavernosum

contains perineal br of pudendal n
helps maintain erection of penis, by compressing the crus of penis, & deep dorsal v of penis
this stops venous return of blood from area
b) Bulbospongiosus m
Origin:
(M) = perineal body, fibrous raphe of bulb of penis
(F) = perineal body
Insertion:
(M) = corpus spongiosum & perineal membrane
(F) = pubic arch, dorsum of clitoris

Action of musc:
(M) = compress bulb of penis, stop venous return –> keep erection,
contraction of corpus spongiosum –> expel urine or semen
(F) = compress eretile tissue of bulb of vestibule –> constrict vaginal orifice

c) Superficial transverse perineal m
ischial rami of tuberosities –> perineal body (tendon)
stabilizes central tendon (perineal body)

d) Perineal body (central tendon)
fibromuscular mass @ center
site of attachment for UG diaphragm m.

e)Bartholin’s gland (bulbourethral glands)
compressed in sex & secrete mucus to lubricate vagina
ducts open in vestibule b/w labia minora below hymen

B. Deep perineal space
b/w sup/inf fascia of UG diaphragm

UG diaphragm
deep transverse perineal m, sphincter urethrae m
b/w 2 pubic rami & ischial rami
inf fascia provide attachment to bulb of penis
pierced by membranous urethrae (M) or urethra & vagina (F)
does not reach pubic symphysis ant

Bulbourethral Glands
lie b/w fibers of sphincter urethrae in deep perineal space
on post/lat side of membranous urethra
ducts pass thru inf fascia of UG diaphragm to open into bulbous part of penile urethra

M of deep perineal space
a)Deep transverse perineal m
inf surface of ischial rami –> med tendionous raphe and perineal body (in Female = vaginal wall)
stabilizes perineal body and supports the prostate and vagina

b) Sphincter Urethrae m
Inf pubic ramus –> median raphe and perineal body
surrounds the body of membranous urethra in male
inf part = attached to ant/lat wall of vagina (F) = urethrovaginal sphincter that compresses urethra and vagina

Anal Triangle
the Post triangle - everything posterior to the line b/w 2 ischial tuberosities

Ischioanal fossa
space lateral to rectum-anal canal, & medial to by levator ani & its fascia that lines the pelvis

Borders:

• ant = post border of sup/deep transverse perineal m
• post = glut max m, sacrotuberous lig
• sup/med = sphincter ani ext + levator ani m
• lat = obturator fascia over obturator ani m
• floor = skin over anal triangle

Contents:

• ischioanal fat
• inf rectal a/v/n (from int pudendal a, pudendal n)
• perineal br of post femoral cut n

On lateral wall, running through obturator fascia = Alcock’s canal aka pudendal canal

• contains pudendal n
• int pudendal a/v

Muscles of Anal Triangle
1. Obturator Internus – lat rotation of thigh
inner surface of obturator mem –> med side of greater trochanter of femur
has tendon that passes around lesser sciatic notch
(n to obturator)

2.Sphincter Ani Ext – closes the anus
Tip of coccyx & anococcygeal lig –> central tendon of perineum (perineal body)
(inf rectal n)

3. Levator Ani m – support and raise pelvic floor
body of pubis, arcus tendonous of levator ani (thickened part of obturator fascia, ishial spine) –> coccyx & anorectal raphe/lig
has 3 parts: puborectalis, pubococcygeus, iliococcygeus
has as ant fibers (most med) = levator prostatae, pubovaginalis
(br of ant rami of S3-4 + perineal br of pudendal n)

4.Coccygeus m – support and raise pelvic floor
ischial spine & sacrospinous lig –> coccyx + lowers sacrum
(br of S4-5)

Pelvic Diaphragm
= levator ani m + coccygeus m
divides pelvis into 2 compartments:
1. superior =  w/ viscera
2. inf = ischiorectal fossa

Pelvic Diaphragm

Inf to pelvic diaphragm = UG diaphragm
is on the ant portion of perineum, and ischioanal fossa posteriorly
made up of sup/inf fascia + deep/sup transverse perineal m
w. perineal body in center

Deep transverse m has urethra & vagina pierce it
m goes around urethra, forms sphincter urethra (M) & urethrovaginal sphincter(F)
does NOT attach to symphysis,
there is a space b/w it and symphysis = retropubic space, where deep/dorsal a of pelvis exit

Nerve Supply:

• Pudendal n (S2-4) -
  • passes thru gr. sciatic foramen, b/w piriformis & coccygeus m –> crosses ischial spine & enters perineum w/ int pudendal a
  • thru lesser sciatic foramen –> pudendal canal
  • Gives rise to:
    • inf rectal n – several br. in canal, crosses ischio-anal fossa => sphincter ani ext m, skin around anus
    • perineal n – arises in canal
      • deep br => all perineal m
      • sup br => br to scrotum, labia majora
• Deep dorsal n - thru perineal mem b/w 2 layers => skin, foreskin, glans
  • lies on dorsum of clitoris or penis

Blood Supply::

• Int pudendal a – leaves pelvis thru gr. sciatic foramen below piriformis & coccygeus m –> enters perineum via lesser sciatic foramen around ischial spine
  • Branches:
    • Inf rectal a - w/ in canal, thru wall of it, br => m and skin around anal canal
    • perineal a – => superficial perineal m, transv perineal br, post scrotal/labial br
    • a of bulb => bulb of penis, bulbourethral glands (M), vestibular bulbs & gr vestibular glands (F)
    • urethral a – corpus spongiosum, glans of penis
    • deep a – pierce perineal mem –> run thru center of corpus cavernosum => erectile tissue of penis & clitoris
    • dorsal a – pierce perineal mem & pass thru suspensory lig of penis/clitoris, runs along dorsum on each side of deep dorsal v and deep to Buck’s fascia & superficial to tunica albuginea => glans & foreskin
• Ext pudendal a- from femoral a
  • runs thru saphenous ring & passes med over spermatic cord (or round ligament of uterus)
  • => skin above pubis, penis, scrotum or labia majora
• Veins of pelvis
  • deep dorsal v -
    • unpaired veins, that begins in sulcus behind glans & lies in dorsal midline ,
    • deep to Buck’s fascia & sup to tunica albuginea –> leaves perineum thru gap b/w arcuate pubic lig & transv. perineal lig –> suspensory lig, below arcuate pubic ligament and drains into –> prostatic and pelvic venous plexus
  • sup dorsal v – runs toward pubic symphysis b/w sup & deep fascia in dorsum of penis
    • divides into R & L br,
    • terminates in sup pudendal v –> drains into gr. saphenous v

Lymph Drainage:

1. Lymph drainage of perineum – occurs via sup inguinal l.n
   • rec lymph from lower ab wall, buttocks, penis, scrotum, labia majora, lower vaginal/anal canal
   • nodes have efferent vessels that drain primarily into –> ext iliac nodes –> lumbar nodes
2. Lymph drainage of Pelvis
   1. • –> common iliac l.n. –> lumbar nodes
   • follows int iliac v –> int iliac nodes –> lumbar nodes
   • Int iliac nodes -rec upper part of rectum, vagina and other pelvic organs
3. upper rectum –> inf mesenteric nodes –> aortic nodes
4. testis/ovaries drains along gonadal vessels –> aortic nodes

Histology : The structure of the matured placenta.

Embryology: The formation of the placenta.

Anatomy of Penis

Anatomy Topic Notecard - Right Click and select "View this Image" to see it larger

Anatomy Topic Notecard - Right Click and select "View this Image" to see it larger

Penis
covered by sup/deep fascia of penis

• b/w the 2 fascia = dorsal cutaneous v
• below = dorsal v in midline, L & R dorsal a lat to it, and most lat is dorsal n

General Info:

• held in back to perineal body (w/ bulbospongiosus m)
• goes through perineal membrane
• lat = fibromuscular tissue = triangular shape
• Function: sexual intercourse, urination

Fascia and Ligaments of Penis:

• Fundiform lig – from linea alba & membranous layer of sup fascia of abdomen –> splits into L& R parts –> encircles body of penis –> blends w/ superficial penile fascia –> scrotum septum
• Suspensory lig of penis – pubis symphysis and arcuate pubic lig –> deep fascia of penis or body of clitoris
  • lies deep to fundiform lig
• Deep fascia of penis (Buck’s fascia) – continuation of deep perineal fascia, cont w/ fascia covering ext oblique m & rectus sheath
• Tunica albuginea – dense fibrous layer that envelopes both corpora cavernosa & corpus spongiosum
  • very dense around corpus cavernosa –> impede venous return & result in extreme rigidity of structures when erectile tissue become engorged w. blood
  • more elastic around spongiosum, therefore not turgid during erection, permist passage of ejaculate
• Tunica vaginalis – double serous membrane, peritoneal sac @ end of process vaginalis
  • covers front and sides of testis and epididymis
  • closed sac derived from ab peritoneum, forming innermost layer of scrotum
  • parietal layer = adjacent to int spermatic fascia
  • visceral layer = adherent to testis & epididymis

Parts:
1. Root
inf ramus of pubis (crus) –> midline of UG diaphragm (bulb) –> penile urethra
located in superficial perineal pouch, b/w perineal membrane sup, and deep perineal fascia inf
Crus of penis = covered by ischiocavernosus m
Bulb of penis = covered by bulbospongiosus m

* More info on these musc/structures will be covered in male perineum

2. Body (shaft)
3 cavernosus bodies:
2 corpus cavernosa
1 corpus spongiosum

has very little muscular fibers in this part
has thin skin, CT, blood & lymph vessles, fascia and the corpora
fill w/ blood during sexual excitement –> erection

Each cavernous body has strong fibrous CT capsule = tunic albuginea

Corpus cavernosum:

• long rod like structures
• from bulk of penis body
• fibromuscular tissue
• Crus of penis lead to corpus cavernosum
• fuse @ midline
• contains the deep a of penis
• tunica albuginea of corpus cavernosa fuse @ midling = form septum penis

Corpus spongiosum:

• b/w & below carvernosa
• tunica albuginea thinner & weaker & blends w. tunic of cavernosum
• carries the urethra
• bulb leads to corpus spongiosum
• NEVER hardens! (otherwise, would depress urethra, no ejaculation)

3. Glans:

• is the head of the penis
• continous w/ foreskin @ coronal sulcus, and via frenulum
• sep from body via corona glandis (sulcus) and location of glands that release the pre-ejaculate
• exit of urethra is on ant tip of glans = vert slit
• extention of corpus spongiosum, and is therefore also soft in erection
• covered by foreskin

Blood supply:

• br of int pudendal a
  • dorsal a – run in space b/w corpora cavernosa, lat to deep dorsal v
  • deep a – peirce crura, run w/in corpora cavernosa
    • supply cavernosus spaces in erectile tissue of corpora cavernosa
    • gives branches called the helicine a
  • a of bulb of penis – supply post corpus spongiosum, bulbourethral gland
• ext pudendal a - supply penile skin
• vein drainage
  • dorsal v of penis in deep fascia –> prostatic venous plexus
  • superficially, –> superficial dorsal v –> superficial ext pudendal v  or lat pudendal v

Lymph Drainage: superficial lymph nodes

Erection:

1. Deep a of penis –> br into helicine a, that run radially & open into cavernae
2. Veins (which drain cavernae) are located in periphery of corpus cavernosum, beside tunica albuginea
3. Helicine a have special smooth m valves = Ebner’s cushions, usually closed & allows minute amount blood in,  drained easily by veins
4. During sexual excitement, Ebner’s cushions open & blood suddenly flow in and fill up cavernae
5. Blood influx compresses veins, so no blood is drained = ERECTION
6. @ end of erection, Ebner’s cushions close, blood flow dec & vein compression release –> cavernae empty

Begins w/ nervous stimulation –> SNS fiber excitation
also involves contraction of bladder sphincter –> so  no urine –> urethra and no semen goes into bladder
Bulbospongiosus m –> propelling force of ejaculation

Histology of Penis

Embryology of Penis

• The genital eminence, an external mound arising between the umbilicus and the tail, is made up of the genital tubercle and the genital swellings.
• The urogenital sinus opens at the base of the genital tubercle, between the genital swellings.
• These structures form identically in male and female embryos up to 7 weeks gestational age.
• At 9 weeks of gestational age, and under the influence of testosterone, the genital tubercle starts to lengthen.
• In addition, the genital swellings (also called the labio-scrotal folds) enlarge and rotate posteriorly.
• As they meet, they begin to fuse from posterior to anterior.
• As the genital tubercle becomes longer, two sets of tissue folds develop on its ventral surface on either side of a developing trough, the urethral groove.
• The more medial endodermal folds will fuse in the ventral midline to form the male urethra.
• The more lateral ectodermal folds will fuse over the developing urethra to form the penile shaft skin and the prepuce.
• As these two layers fuse from posterior to anterior, they leave behind a skin line: the median raphe.

By 13 weeks, the urethra is almost complete. A ring of ectoderm forms just proximal to the developing glans penis. This skin advances over the corona glandis and eventually covers the glans entirely as the prepuce or foreskin.

Development of the male external genitalia is dependent upon dihydrotestosterone which is produced by the testes. As the genital tubercle is elongating and growing to form the penis, the urogenital folds which lie on either side of the urogenital membrane begin to move towards each other forming a groove, this is known as the urethral groove. The urogenital folds fuse together on the ventral side of the developing penis, enclosing what will now become the spongy urethra. If the urogenital folds fail to close, hypospadias results.

The tip of the penis, which is now called the glans, then begins to form a cord of ectoderm which grows toward the spongy urethra. This cord is known as the urethral plate and when it canalizes, the end of the urethra (external urethral orifice) is at the tip of the penis.

The foreskin is formed in the twelfth week of development. A septum of ectoderm moves inward around the edges of the penis and then breaks down, leaving a thin layer of skin surrounding the penis. During this time, the penis is also developing its corpus cavernosa and spongiosa from proliferating mesenchyme within the genital tubercle.

The labioscrotal folds also grow towards each other and fuse during development to form the scrotum.

Anatomy of the ureter, urinary vesicle and urethra.

Ureter

*retroperitoneal
General Info:
musc tube that transmit urine via peristaltic waves, leads from kidney
is the most posterior structure that emerges from hilus of kidney
25-30 cm long
enter bladder @ anteromedially, superior to levator ani

Topography:

• crosses bifurcation of common iliac a @ pelvic brim
• desc retroperitoneally on lat pelvic wall –> med to umbilical a & obturator a/v
• post to ovary @ post surface of ovarian fossa
• 1-2 cm lat to uterus, runs w/ uterine a, which runs above and ant to base of broad lig
• passes post/inf to ductus deferens & lies in front of seminal vesicle before entering post/lat bladder (male)

2 parts – abdominal/pelvis

Abdominal
crossed by 3 structures: Topography
1. Gonadal a/v – in front
2. Psoas major – behind
3. Bifurcation of common iliac a w/ ureter in front of int iliac a

Male – ductus deferens crosses ureter in front

Female

• uterine a crosses in front
• @ bifurcation of common iliac, forms post border of ovarian fossa
• contacts lat fornix of vagina b4 entering bladder

Blood Supply:

• rec blood from aorta, renal, gonadal, common & int iliac, umbilical, sup/inf vesicle a, middle rectal a
• Vesicle venous plexus –> int iliac v (sometimes, prostatic vesicle plexus)

Lymph Drainage: lumbar, common iliac, ext iliac, int iliac l.n

Urinary Bladder

*Infraperitoneal – lower in female
located in pelvis minor when empty
located full, can enter major pelvis –> even up to umbilicus

General Info:

• THICK muscular wall = detrusor m
• holds urine, until ready to release it
• mucus membrane attaches, except @ trigone
  • mucus membrane attaches to CT underlying, no mucosal folds
  • originates from mesonephric duct
  • marked by entrances of ureter & ejaculatory duct
  • has 2 ureteric openings and urethral openings (int urethral sphincter)
• anchored by CT ligaments = paracysticum
• held @ neck  to pubic bone, via puboprostatic (male), or pubovesical (female) ligaments

Structure of Bladder (Detail):

The bladder itself consists of 4 layers:-

(1) Serous – this outer layer being a partial layer derived from the peritoneum,
(2) Muscular – the detrusor muscle of the urinary bladder wall, which consists of 3 layers incl. both longitudinal and circularly arranged muscle fibres,
(3) Sub-mucous – a thin layer of areolar tissue loosely connecting the muscular layer with the mucous layer
(4) Mucous – the innermost layer of the wall of the urinary bladder loosely attached to the (strong and substantial) muscular layer. The mucosa falls into many folds known as rugae when the bladder is empty or near empty.

• The features observable on the inside of the bladder are the ureter orifices, the trigone, and the internal orifice of the urethra.
• The trigone is a smooth triangular region between the openings of the two ureters and the urethra and never presents any rugae even when the bladder is empty – because this area is more tightly bound to its outer layer of bladder tissue.

Peritoneal relations of bladder:

Outer surfaces of the Bladder: The upper and side surfaces of the bladder are covered by peritoneum (also called “serosa”). This serous membrane of the abdominal cavity consists of mesthelium and elastic fibrous connective tissue. “Visceral peritoneum” covers the bladder and other abdominal organs, while “parietal peritoneum” lines the abdomen walls.

Topography of Bladder: Bladder Bed

• ant = pubic bone, separated from ant ab wall & pelvis by rectopubic space
• inf/lat = obturator int m, levator ani m
• inf/post = rectum

B/w bladder & rectum:
Male – seminal vesicles & ejaculatory duct, ductus deferens
Female - uterus & upper vagina

Vesicouterine Pouch:
ant = bladder
post = uterus
lat = vesicouterine ligaments (folds)

Normally, pouch so small, there is nothing in it
If Rectoversion occurs, may contain SI loops
bladder connected to CT except @ neck where puboprostatic lig anchors it (male)

Rectovesicle Pouch:
ant = bladder, seminal vesicle, DD
post = rectum
lat = rectovesicular fold

In male, pertioneum covers fundus, reflecting from upper post wall, and covers tip of seminal vesicle

Parts of Bladder:

1. Apex (ant end)
   • retro to symphysis
   • origin of median umbilical ligament – remnant of embryonic urachus (connection b/w urinary bladder and embryonic allantois)
2. Fundus (post/inf)
   • contact w/ rectum in male, separated by rectovesicular septum
   • contacts w/ ant surface of vagina in female
3. Neck (lat/post — converges here)
   • urethra originates from bladder here
   • just above = uvula – small eminence projects into urethra

Blood Supply:

• Sup vesicle a (int iliac a)
• Fundus of bladder
  • inf vesicle a (Male)
  • vaginal a (uterine a – Female)
• veins = vesicle venous plexus –> int iliac v (prostatic venous plexus)

Lymph Drainage:

• body = ext iliac lymph nodes
• fundus = int iliac l.n
  
• neck = sacral & common iliac l.n.

Innervation:

• PNS from pelvic splanchnic n (S2-4)
  • VM for detrusor m
  • (-) for int urethral sphincter
• SNS (T12-L2)
  • VM for int urethral sphincter
  • (-) detrusor m

Urethra
From bladder –> opens @ perineum, urine emptied thru it

Male Urethra

Parts to it:
1. Prostatic urethra
3 cm long, and w/in prostate
widest part of urethra
covered w/ urothelium = transitional epithelium

The prostatic urethra begins at the neck of the bladder and includes all of the section that passes through the prostrate gland. It is the widest and most dilatable part of the male urethral canal.

Structures opening here:
1. Prostatic glands
2. Ejaculatory ducts
3. Prostatic utricle

long ridge = urethral crest

• runs through out w/ 2 grooves beside it = prostatic sinuses
• opening of submucosal ducts & prostatic glands
• @ upper crest = seminal collicus

Seminal colliculus

• small hill like structures protruding into urethra
• lat to colliculus are prostatic sinuses, where prostate glands open
• 3 small openings:
  • @ midline = utricle of prostate (remnant of paramesonephric duct - regresses in male)
  • inf to that = 2 ejaculatory ducts

secretions of prostate, seminal vesicle, and bulbourethral glands mixes w/ spermatozoa from testis = semen

2. Membranous urethra
1 cm long
passes thru UG diaphragm – here ext urethral sphincter seen

The membranous urethra is the shortest and narrowest part of the male urethra. This section measures approx. 0.5 – 0.75 inches (12 – 19 mm) in length and is the section of the urethra that passes through the male urogenital diaphragm.
The external urethral sphincter (muscle) is located in the urogenital diaphragm (as for the female urethra).
The passage of urine along the urethra through the urogenital diaphragm is controlled by the external urethral sphincter, which is a circular muscle under voluntary control (that is, it is innervated by the somatic nervous system, SNS).

3. Penile urethra
enters bulbous part of  penis
Pathway: turns up @ sharp angle (1st turn)  –> runs along bulb of penis –> to pubic symphysis –> bends down (2nd turn) –> corpus spongiosum –> runs down to tip of penis & opens @ navicular fossa

The spongy (penile) urethra is the longest of the three sections. It is approx. 6 inches (150 mm) in length and is contained in the corpus spongiosum that extends from the end of the membranous portion, passes through the penis, and terminates at the external orifice of the urethra – which is the point at which the urine leaves the body.

@ navicular fossa: str columnar –> str sq non keratinazing epith

CLINICAL NOTE: B/c of 2 sharp bends – makes it difficult to insert catheter

Blood supply: prostatic br of inf vesicle a & middle rectal a, v follow a

Lymph Drainage: int/ext iliac l.n

Nerve supply: pudendal n, prostatic plexus (inf hypogastric plexus)

Female urethra

At only about 1.5 inches (35 mm) long, the female adult urethra is shorter than the adult male urethra (approx. or 8 inches, or 200mm). The female urethra is located immediately behind (posterior to) the pubic symphysis and is embedded into the front wall of the vagina.

The urethra itself is a narrow membranous canal that consists of three layers:

1. Muscular layer – continuous with the muscular layer of the bladder, this extends the full length of the urethra.
2. Thin layer of spongy erectile tissue – including plexus of veins and bundles of smooth muscle fibres. Located immediately below the mucous layer.
3. Mucous layer – internally continuous with the bladder and lined with laminated epithelium that is transitional near to the bladder.

After passing through the urogenital diaphragm (as shown in the diagram), the female urethra ends at the external orifice of urethra – which is the point at which the urine leaves the body. This is located between the clitoris and the vaginal opening.

The passage of urine along the urethra through the urogenital diaphragm is controlled by the external urethral sphincter, which is a circular muscle under voluntary control (that is, it is innervated by the somatic nervous system, SNS).

The female urethra is a much simpler structure than the male urethra because it carries only urine (whereas the male urethra also serves as a duct for the ejaculation of semen – as part of its reproductive function
upper 1/2 = prostatic urethra
lower 1/2 = “membranous”

@ upper part = Paraurethral glands –> ducts @ ext urethral orifice

@ lower part
goes through UG diaphragm
transverse perineal m wraps around to form = urethro vaginal sphincter
closely associated w/ ant wall of vagina

• attached via strong CT sheath = urethrovaginal septum
• b/w them = urethrovaginal space

Blood supply: int pudendal a, vaginal a, veins follow a

Lymph Drainage: sacral/int iliac l.n

Nerve supply: pudendal n

Process of Urination:
Initiated by (+) of stretch receptors in detrusor m in bladder in wall by inc volume of uring
innervated by S2-4 via pelvic splanchnic n
can be assisted by contraction of abdominal m = inc intra abdominal & pelvic pressures

Process:
1. SNS = (+) relaxation of bladder wall
contract inner sphincter –> (-) emptying
may stimulate detrusor m to prevent reflux of semen into bladder during ejaculation

2. PNS = preggl fibers in pelvis splanchnic n
synapse in pelvic (inf hypogastric plexus)
post ggl to bladder musc induc reflex = contraction of detrusor m
and relaxation of int sphincter
inc urge to urinate

3. SM fibers in pudendal n cause voluntary relaxation of ext urethral sphincter
bladder begins to release

4. @ end of urination
the ext urethral sphincter ( & bulbospongiosus m in male) contracts
expel the last few drops of urine from urethra

Histology  of the ureter, urinary vesicle and urethra.

Slide #63 Ureter * H&E

Structures to Identify:

• 3 layers = mucosa, muscularis, adventia
• transitional epith
• umbrella cells
• a/v
• CT
• piriform cells
• basal cells

General Info

• paired tubular structures that convey urine from kidney –> bladder
• lined w/ transitional epith to adapt to changing environment (fluid v no fluid)

Mucosa

• Epith = urothelium
  • thick, with cells that change shape
• star shaped irregular lumen, made by mucosal folds, due to musc. contractions
• Note that lumen is long , narrow and star shaped, not circular *like DD
• 3 main cell types of Epith
  • umbrella cells – come in contact with urine, and adjust accordingly, can be bi-nucleated, shape change due to actin filaments
  • piriform cells – underneath umbrella cells and above basal cells, can also adjust morphologically
  • basal cells – located at lowest layer of stratified epith
• LP = fibroelastic CT, denser near epith –> looser towards muscularis ext, with diffuse lymph tissue = MALT
• No real muscularis mucosae

transitional epithelium or urothelium and cells of it

Muscularis Ext

• 3 layers:
  • inner longitudinal layer
  • middle circular layer
  • outer longitudinal – but only in last 1/3 of ureter
• smooth m responsible for creating peristaltic contractions to convey urine through ureter (30cm)

Adventia

• 3rd main layer
• ureter = retroperitoneal, so covered w/ adventia
• CT + a/v/n
• adipose

Slide #64 Urinary Bladder * H&E

Contracted Bladder - Our slide doesnt look like this, but this shows layers well

Structures to Identify:

• urothelium
• muscularis
• a/v
• CT
• mesothelium
• PNS ggl

General Info

• Receives urine from 2 ureters and under appropriate stimulation, will secrete it through urethra
• lined by urothelium, which allows bladder to adjust to amount of urine

Mucosa

• Epith = urothelium,  transitional epithelium
  • same cell types as ureter
  • up to 10 layers when bladder empty, # layers dec when bladder is full
• when bladder is full, cells flatten and appear squamous, & when bladder was empty, cells became dome shaped
• LP = CT tissue fibers, fibroblasts, a/v, many layers
  • Can either say LP has 2 layers = upper cell rich, and lower fibrous layer
  • Or can say there is a cell rich LP with a fibrous submucosa
  • fibrous layer not present in bladder trigone
• changes in appearence and cells shapes in transitional epithelium are from thickened regions called plaques
  • interconnected via interplaque regions
  • allow  cell membrane to fold – which disappear when urine flows into bladder

Muscularis Mucosae

• 3 muscular layers: – inner longitudinal, middle circular, outer longitudinal
• not as organized as ureter
• may be ggl cells wich are part of ANS
  • helps regulate urine secretion via relaxation & contraction of muscularis
  • controls detrusor m
• Internal urethral sphincter = fromed @ site of entry of bladder –> Urethra
• w/ CT in between, and a/v and capillaries, and occasional n. fibers

Adventia

• Infraperitoneal
• fundus covered by peritoneum
• serosa/ subserosa can be present where peritoneal pres – superiorly –> simple squamous = mesothelial cells
• SNS n fibers maybe

Beyond the serosa/adventitia covering of the bladder is perivesical fat.  This is a layer of fat surrounding bladder.

It's upside down - sorry

Slide #71 Penile Urethra * H&E

Structures to Identify:

• lumen
• corpus spongiosum
• smooth m
• str columnar/ psuedo str columnar
• tunica albuginea
• urethral glands of Littre
• paraurethral ducts
• endo-epith glands

Mucosa

• Epith = pseudostratified non keratinized epith
  • epith changes depend on part of urethra
  • Pars prostatica -  urothelium
  • Pars membranous – str columnar
  • Pars spongiosum -  str columnar – until navicular fossa – str squamous
• LP = thin layer, merges with surrounding corpus spongiosum, cell rich
• lumen is shaped like ureter, but does NOT have urothelium in our slide, so look for that, and the glands of Littre
• mucosal folds makes small dips in lumen, and forms lacunae
• lacunae attached to urethral ducts of urethral glands of Littre
  • mucus secretions
  • thin basophillic (blue) outer layer with pale interior (mucus)
  • duct is more basophillic, with small circular lumen

Corpus spongiosum

• network  of cavities lined by simple squamous epith
• a/v in b/w

Outer layer = Tunica albuginea

• thick eosinophillic layer, with smooth m and elastic fibers

Ducts of Littre

Development of the ureter, urinary vesicle and urethra.

Ureter:

• intermediate mesoderm forms longitudinal ridge on post body wall = urogenital ridge
• part of UG ridge becomes nephrogenic cord –> urinary system
• nephrogenic cord develops into 3 structures: pronephros, mesonephros, metanephros
• metanephros further develops from ureteric bud and from grouping of mesoderm w/in nephrogenic cord, metanephric mesoderm
• further development of ureteric bud –> becomes ureters
  

Urinary bladder:

• urinary bladder is formed from upper end of urogenital sinus, continuous w/ allantois
• allantois becomes fibrous cord = urachus * stays in adult as median umbilical lig
• lower end of mesonephric ducts –> post wall of bladder as trigone
• mesonephric ducts open into urogenital sinus below bladder
• transitional epith from endoderm
  

Urethra:

Female Urethra:

• female urethra is formed from lower end of urogenital sinus
• develops as endodermal outgrowths into surrounding mesoderm = urethral glands, paraurethral glands
• end @ vestibule of vagina, also forms from urogenital sinus
• vestibule of vagina – develop endoderm growths = greater vestibular glands
• endoderm = epith
  

Male Urethra:

• Prostatic urethra, membranous urethra, prox urethra
  • formed from lower end of urogenital sinus
  • endoderm = transitional epith, str columnar epith
  • prostatic urethra have endoderm outgrowth into mesoderm = prostate gland
  • membranous urethra have endoderm outgrowth into mesodem = bulbourethral glands
  • prox part of penile urethra have endoderm outgrowth into mesoderm = Littre’s glands
• distal part of penile urethra
  • formed from ingrowth of surface ectoderm = glandular plate
  • glandular plate joins penile urethra and becomes tube = navicular fossa
  • ectodermal septa lat to navicular fossa –> becomes foreskin
  • str sq epith lines part of urethra = ectoderm

Anatomy of Seminal Vesicle & Prostate Gland

Seminal Vesicle:
*Retroperitoneal, except the tip, which is intraperitoneal

General Info:

• long tube (10-15cm), that coils down into 5cm
• produces seminal fluid – alkaline substance, w/ fructose, choline
• enclosed by dense endopelvic fascia
• are lobular glandulated structures that are actually pockets that formed off of the DD
• lower end becomes narrow & from ducts which join ampulla of DD –> make ejaculatory duct
• Does NOT store spermatozoa

Topography:

• @ post side of prostate
• located inf/lat to ampulla of DD, against the fundus of the bladder
• tip lie post to ureters, where peritoneum of rectovesical pouch separates it from rectum
• inf end separated from rectum via rectovesical septum

Blood Supply:

• inf vesicle a/v (int iliac a)
• middle rectal a/b (int iliac a)

Lymph Drainage: int iliac l.n.

Nerve Supply:
SNS - controls rapid contraction, during ejaculation - superior lumbar & hypogastric n
PNS - pelvic splanchnic n, inf hypogastric (pelvic) plexus

Ejaculatory Duct:

General Info:

• union of ductus deferens
• formed @ neck of bladder
• enters prostate @ post surface –> runs down, med, forward –> opens lateral to seminal collicus, on prostate urticle on post wall of prostatic urethra
• peristaltic contractions of musc layer of ductus deferens & ejaculatory ducts
• propel spermatozoa w/ seminal fluid into urethra

Blood Supply: deferential a (inf vesicle a)
veins –> prostatic and vesical venous plexus

Lymph drainage: ext iliac l.n.

Nerve supply: inf hypogastric plexus

Prostate
below the bladder, and is around prostatic urethra
prostatic capsule – has a dense CT fibrous capsule
prostatic sheath – has a soft CT capsule around fibrous one – derived from pelvic fascia
is continuous w/ paraproctium (the CT fibers around rectum), and paracysticum (CT fibers around bladder)

Two parts:
Glandular portion (2/3)
lat – make most of pass of prostate, lat to urethra
post – behind urethra, below ejaculatory duct CLINICAL NOTE – is palpable via rectal exam
med – around urethra, b/w it and ejaculatory duct

• Prostatic glands – produces seminal fluid that causes odor of semen
  • contains Prostatic specific antigen (PSA), prostaglandins, citric acid, acid phosphatase, proteolytic enzymes
  • make about 20% of seminal fluid
  • this fluid + secretions of seminal vesicles + secretions of bulbourethral glands + sperm = semen
• Urethral crest:
  • on post wall of prostatic urethra, and has # of openings for prostatic ducts on either side
  • has ovoid shaped enlargement called seminal collicus - where 2 ejaculatory ducts, prostatic utricle open
  • @ top of colliclus = prostatic utricle, small impression (analogous to female vagina)
• Prostatic sinus:
  • groove b/w urethral crest & wall of prostatic urethra
  • rec duct of prostate glands

Fibromuscular portion (1/3)
ant – ant to urethra, no glandular substance

Topography:

• ant = pelvic wall, musc fibers, has retroperitoneal fat in front of it, b/w it and pubic symphysis
• post = seminal vesicle, ductus deferens, ampulla of rectum
• sup = bladder
• inf = urethral sphincter, deep perineal m, UG diaphragm, levator ani

Blood supply: inf vesicle a, middle rectal a
drained by prostatic venous plexus (b/w  fibrous capsule & prostatic sheath) –> int iliac v

Nerve supply:
Both PNS/SNS to contract smooth m
PNS – pelvic splanchnic n (S2-S4)
SNS – inf hypogastric plexus

Histology of Seminal Vesicle & Prostate Gland

Slide # 69 Prostate *H&E

Structures to Identify:

• prostatic glands
• capsule
• glandular epithelium
• smooth m
• excretory ducts
• prostatic stones
• CT stroma

General Info:

• located inferior to neck of bladder
• seminal vesicle combine with the ductus deferens and open as ejaculatory duct here
• surrounded by dense CT capusle
• urethra leaves bladder and passes through bladder, and is called prostatic urethra.
• largest  accessory sex gland, several functional zones
• 30-50 glands arranged in concentric layers = mucosal, submucosal, and peripheral
  • Mucosal –> secrete directly into urethra
  • Submucosal/Peripheral –> secrete into urethra via ducts
• Secretions
  • Citric acid
  • Fibronalysin
  • Serine Protease (PSA) –> Clinical NOTE: if increased, can be early sign of prostatic cancer

Epith: transitional (urothelium) epithelium

Prostatic Glands

• look like popcorn
• have glandular epith = simple columar epith –> cuboidal
• are small, branched tubulo acinar glands
• may have circular very pink prostatic stones
  • calcifications of cellular debris in the gland
  • # increases with age
  • Very characteristic of prostate. — LOOK FOR THESE, if u think it is the prostate.
• between glands = fibromuscular stroma, with loads of smooth m bundles, and collagen and elastic fibers

Prostatic stones

The stroma encircles an area called the seminal collicus, that has no glands

At top of seminal collicus, is located the C shaped urethra, with the utricle underneath. Ejaculatory ducts open on either side of utricle

*cant see uticle and ejaculatory ducts in slide, but need to know them theoretically

on the lateral sides of the collicus are the prostatic sinuses (the end of the C), where the ducts of the glands open into.

Excretory ducts: columnar epith, stains darker than glands

Slide # 68 Seminal Vescicle *H&E

Structures to Identify:

• epithelium
• LP
• 2 muscular layers = circular, longitudinal
• irregular large lumen, with mucosal folds
  
• ductus deferens, if seen

General Info:

• an outgrowth of the ductus deferens
• produce yellowish, viscous fluid,  that contains high amt of fructose,which is energy for sperm
• produce most of the fluid found in semen
• are elongated glands on the posterior side of the bladder
• duct of seminal vesicle combines with ductus deferens to make ejaculatory duct
• vesicles are single tubes whcih are coiled and folded on themselves
• in cross section, look like separate lumens, but it is all one

Secretions contain:

• fructose
• other simple sugars
• amino acids
• ascorbic acids
• prostaglandins (originally discovered in prostate, IMP in inflammatory processes)

Cross section through region of ampulla of DD, so can see both DD and seminal vesicle

Ampulla muscular coat, tinner than rest of DD, and has secretory epithelium

Mucosa

• Epith = columnar or pseudostratified columnar, very invaginated (kinda looks like lumen of gallbladder)
• has mucosal crypts, made by infoldings of the mucosa
• LP
  • smooth m
  • rich in elastic fibers
  • very cell rich
  • goes into the primary mucosal folds
• secondary mucosal folds are the ones that u cant see open up into epithelium (look like closed sacs)

Muscular Layer

• rest on thick layer of smooth m cont w. DD
• smooth musch has inner circular and outer longitudinal layer
• contractions of smooth m. wall during ejaculation pushes substances through ejaculatory duct

Adventia – no peritoneal covering

Embryology  of Seminal Vesicle & Prostate Gland

Genital Duct formation:
Paramesonephric duct starts to develop, but later regresses, due to MIF

Mesonephric duct forms = epididymis, ductus deferens, seminal vesicle, ejaculatory duct, efferent ducts of testis

Anatomy of Testis, Epididymis & Ductus Deferens

Scrotum:
cut pouch of thin pigmented skin and underlying tunica dartos, a facial layer cont w/ superficial penile fascia and superficial perineal fascia

Function:

• NO fat – to maintain temperature lower than rest of body
• contains testis and epididymis
• the dartos m. w/in tunica dartos attaches to the skin – it controls the wrinkling of skin of scrotum
  
  • contracted and wrinkled when cold (or sexually stimulated), bring testis in close contact w/ body to conserve heat
  • relaxed when warm and hence is flaccid and more pendulous to release and spread heat
  • By transferring the testicles into the scrotum a testicular temperature 2-3 ºC lower than body temperature is attained.  Lower temperature is necessary for producing sperm cells.

Structure

• divided into R & L compartments via scrotal septum (int) and scrotal raphe (ext)
• superficial dartos fascia – has no subcutaenous fat, like Scarpa’s fascia of the abdomen

Testis
* considered retroperitoneal

General Info:

• covered by visceral layer of tunica vaginalis testis - except where in contact w/ epididymis – covered by tunica albuginea
• attached to scrotum via gubernaculum testis -
  
  • remnant of embryonic caudal ligament
    
  • responsible for pulling down testis from ab cavity –> scrotum
  • analogous to round ligament in female

Function: produce spermatozoa (spermatogenesis) and secrete sex hormones

Spermatogenesis: production of spermatids, not mature sperm cells yet.  (spermiogenesis covered in next topic, w/ seminal vesicle and prostate)

Anim: http://highered.mcgraw-hill.com/olc/dl/120112/anim0043.swf

• Spermatogenesis is initiated in the male testis with the beginning of puberty. This comprises the entire development of the spermatogonia (former primordial germ cells) up to sperm cells. The gonadal cords that are solid up till then in the juvenile testis develop a lumen with the start of puberty. They then gradually transform themselves into spermatic canals They are termed convoluted seminiferous tubules (Tubuli seminiferi contorti) . They are coated by a germinal epithelium that exhibits two differing cell populations: some are sustentacular cells (= Sertoli’s cells) and the great majority are the germ cells in various stages of division and differentiation.
• development of the germ cells begins with the spermatogonia at the periphery of the seminiferous tubule and advances towards the lumen over spermatocytes I (primary spermatocytes), spermatocytes II (secondary spermatocytes), spermatids and finally to mature sperm cells.
• The Sertoli cell is essential for spermatogenesis as it provides support for the developing sperm cells – moving them towards the lumen of the semiferous tubule as they develop until maturity when they are released. The Sertoli cell also reduces motility and capacitation (initiation of the acrosome reaction) of the sperm cells so viability is maintained.
• Spermatozoa are produced in seminiferous tubules in the testes. They start off as spermatogonia , undergoing mitosis becoming a type A spermatogonium or a type B spermatogonium.
  • Type B spermatogonia become primary spermatocytes.
  • Primary spermatocytes go through a meiotic division to become secondary spermatocytes, which undergo another meiotic division to become spermatids.
  • Type A spermatogonia stay as spermatogonia, and do not change. They act as stem cells and will divide again producing more Type A and B cells.
• The primary spermatocytes contain twice the DNA of a normal body cell (2 × 2N).
  • Each primary spermatocyte divides into two secondary spermatocytes containing two sets of chromosomes (2 × 1N).
  • The secondary spermatocytes then divide into two spermatids, each containing just one set of chromosomes (1N), half the DNA needed to make a human being. (The other half will come from the ovum at fertilisation)

Tunica Vaginalis & processes vaginalis testis:

• fluid filled envelope
• testis attached to scrotum thru caudal lig of testis  & to peritoneum running above it
• During descent of testis, pertinoneum is pulled in to scrotal sac w/ testis = processes vaginalis testis –> become tunica vaginalis
• have a visceral and parietal layer, just like peritoneum

Blood supply:
testicular a (ab aorta)
drained by v of pampiniform plexus –> become testicular v

Lymph vessels in area –> sup inguinal nodes & lumbar nodes

Epididymis:

• formed by the many twists and turns made by the 1 epididymal duct
• lies of post surface of testis, – only place where testis not covered by tunica vaginalis
• has head, body, tail
  
  • head – made up of 12-14 efferent ducts, leading from rete testis
  • body – duct of epididymis
  • tail – continous w/ ductus deferens

Ductus Deferens:

Function:

• continuation of epididymal duct
• carries spermatozoa from testis/epididymis to prostatic urethra
• unites w. duct of seminal vesicle to form ejaculatory duct
• Terminal portion = ampulla, med to seminal vesicle
• opens lat to seminal collicus on post wall of prostatic urethra

Pathway/Topography:

• begins in tail of epididymis –> asc w/ spermatic cord –> inguinal canal –> enter  retroperitoneal space @ deep inguinal ring –> desc to bladder
• int iliac a (DD runs in front)
• ureter (DD runs in front)
• no structure runs b/w peritoneum and DD

Blood supply: deferential a (usually inf vesicle a, sometimes sup vesicle a), joins testicular a w/in scrotum,

Veins = v run w/ a

Lymph Drainage = ext iliac lymph nodes

Nerve supply: inf hypogastric plexus
SNS – causes rapid contracting of musc during ejaculation

Spermatic Cord:

• develop from genital folds of embryo (analogous to labia majora)
• L & R  genital folds join to form scrotal raphe in midline of scrotal sac

Pathway:
Deep inguinal ring lat to lat umbilical fold (w/ inf epigastric a/v inside)
–> thru inguinal canal –> exit @ superficial inguinal ring –> scrotum @ post border of testis

Because the testis form in abdominal cavity, and then descends into scrotal sac, the layers of ab wall accompany this trip, and so the same layers can be seen in both spermatic cord, and scrotum

Layers of Ab wall are continuous w/ layer of Spermatic cord:

Contents of Spermatic cord:
1. Ductus deferens – originates from epididymis & carries spermatozoa

2. Arteries

1. Testicular a – paired visceral branches of ab aorta w/ pampiniform vein plexus = testis & epididymis
2. Deferential a (a of ductus deferens) – from inf vesicle artery = ductus deferens itself
3. Cremasteric a (from inf epigastric a) = cremasteric m

3. Pampiniform plexus - network of v around testicular a and ductus deferens –> ends as testicular v, cools down blood that enters testis

4. Nerves

• Genital br of genitofemoral n (lumbar plexus) = Cremaster m
• Autonomic fibers = regulate smooth m of ductus deferens and a/v (VM), and carry VS from testis
  • SNS regulates the a/v, and PNS regulates the DD itself
    

5. Lymph vessels –> sup inguinal nodes

Blood supply:

• int pudendal a (int iliac a)
• Ext pudendal a (femoral a)
• testicular a (ab aorta)
• cremasteric a
• all flow –> testicular v

Innervation:

• Ilioinguinal n
• pudendal n
• perineal br of post cut femoral n
• genital br of genitofemoral n

Histology of Testis, Epididymis & Ductus Deferens

Slide # 65 Testis & Epididymis

Structures to Identify:

• Sertoli cells (in semineferous tubules)
• Leydig cells
• Tunica Albuginea
• Epididymis
  
• CT septa
• Ductus Efferents
• Ductus epidymis
  
• Straight Tubules
• Rete Testis

General Info:

• covered by thick CT capsule = tunica albuginea
• just below tunica albuginea, is a layer of a/v =  tunica vaculosa
• on the posterior side of the testis, the tunica albuginea pushes into the testis to form the mediastiunum testis
• thin sheets come from the mediastinum testis to form septa between the 250 testicular lobules
• Each lobule has 1-4 seminiferous tubules, lined by stratified germinal epithelium (same epith like uterus)
  • Epith contains = germ cells, and Sertoli cells
• Between the seminiferous tubules, are fibroblasts, muscle like cells, a/v/n, and lymphvessels and Leydig cells
• Leydig cells = produce testosterone

Seminiferous Tubules

• 1-4 in each lobule
• triangular nucleus
• produce spermatids
• 1st layer = in epith of tubules = Sertoli cells *more later*
  
• Contain spermatogenic cells in 2nd layer – b/w sertolis cells and lumen
  • regularly replicating and differentiating
  • organized poorly into layers
• 3rd layer = Tunica Propria
  
  • also called peritubular tissue
  • myoid cells sit beneath the basal lamina of Sertoli cells = nursing cells
  • contraction of myoid cells create peristaltic movement
  • if thickens in early life —> Infertility
• Basal compartment = spermatogonia, primary spermacytes
• Lumen = mature spermacytes, spermatids
• surrounded by interstitial tissue

Interstitial Tissue

• a/v
• loose CT
• clusters of epithelial like cells of Leydig
  • eosinophillic, round nucleus
  • lipid droplets
  • crystal of Reifkle = Rectangular, crystal-like inclusions in the interstitial cells of the testis (Leydig cells) and hilus cells in the ovary.
  • elaborate Smooth ER for enzyme production
  • testosterone production
    • in early fetal life = help male gonads develop
    • in Puberty = sperm production, pubic hair growht
    • In Adult = maintenance of sex glands, spermatogenesis

Sertoli Cells = tall columnar, non replicating cells that rest on basal lamina, 5 functions

1. Supporting cells – processes for exchange of metabolic substances and waste
2. Phagocytes – junctional complexes, and spermatogonia cells that don’t complete differentiation
3. Endocrine – Androgen Binding Protein (ABP) - binds testosterone from Leydig cells for proper maturation of spermatozoa, secrete fluid for passing mature sperim
4. Exocrine – secrete hormones
   • Inhibin – inhibits FSH release
   • Transferrin – Fe transport
   • Plasminogen activators – stimulate proteolytic enzymes
5. Help form Blood Testis Barrier
   • fluid in seminiferous tubules different from plasma – i.e diff amino acids, ions, carbs
   • protect genetically differentiating cells from immune system
   • junctional barrier
   • The barrier is formed by layers of cells from the VASCULAR ENDOTHELIUM of the capillary BLOOD VESSELS, to the SEMINIFEROUS EPITHELIUM of the seminiferous tubules. TIGHT JUNCTIONS form between adjacent SERTOLI CELLS, as well as between the ENDOTHELIAL CELLS.

Sperm is made and modified through the testicular duct system

Pathway: Seminiferous tubules (convoluted/straight tubules) --> rete testis (in mediastinum testis) --> Efferent ducts --> Epididymis ducts (tail, body, then head) --> ductus deferens

Pathway: Seminiferous tubules (convoluted/straight tubules) –> rete testis (in mediastinum testis) –> Efferent ducts –> Epididymis ducts (tail, body, then head) –> ductus deferens

First 4 you can identify in this slide, each one has different epithelial lining and function

Straight tubules: short narrow ducts, with cuboidal lining epith , no spermatogenic cells

Rete Testis: @ mediastinum testis,

• network of tubules wth wide lumen
• epith goes from simple squamous to low cuboidal to low columnar.
• widen near the efferent ducts

Epididymis:

• include efferent ducts and ducts of epididymis
• 4-6 M long coiled structure
• newly produced sperm mature here –> gain motility and ability of fertilize female oocyte
• head of sperm modified by addition of depcacitation factor, containing  carb like fluid which inhibits a second fertilization of the egg – IMP for transfer of DNA content
• fluid is released during capacitation in female reproductive tract — IMP for binding to oocyte
• lined by  pseudo stratified columnar epith, with primary cells and basal cells that have stereociliae
• lymphocytes are also present
• resevoir of sperm
• when stimulated – contraction occurs, ejaculation occurs

Ductus efferentes

notice the star shaped lumen - efferent ducts

• star shaped lumen –> due to tall ciliated cells, and shorter non ciliated cells
• found nearer to mediastinum
• surrounded by CT
• form part of head of epididymis
• reabsorb fluid secreted from seminiferous tubules
• musc layer surrounds ducts to push sperm forward

Ductus epididymis

Epididymal ducts: PRINCIPAL CELLS, are elongated and located at the base. Another population of cells has a rounder nucleus and can be found mainly at the base (called BASAL CELLS)

• pseudostratified columnar epith
• one tube that is convoluted and twisted, so you are seeing mutliple cross sections of its lumen
• has tall columnar principal cells with non motile stero cilia, and small basal cells (circular and at base)
• smooth round lumen
• located towards the outside, away from the medistinum testis

Slide #67 Ductus Deferens in Spermatic Cord

Structures to identify:

• pseudostratified columnar epith w/ sterocilia
  
• all 3 layers of muscle – inner longitudinal, middle circular, outer longitudinal (like in ureter)
  
• a/v/n
• adventia
• smooth and skeletal m

*Slide easy to identify as you can also see many other structures with it, and also do not confuse with ureter or urethra, this does not have urothelium, and the urethra’s lumen is long, and thin and irregular. This lumen is wide, kinda circular, and irregular.

General Info:

• tiny narrow irregular lumen, with mucosal foldings into it = glandular diverticuli.
  
• thin mucosa – LP has collagen fibers, and elastic fibers
• THICK muscular layer
• no submucosa or musc mucosa
• adventia = no peritoneal relationship

Embryology of Testis, Epididymis & Ductus Deferens

Development of Testis, Epididymis, Ductus Deferens
Until week 6, the embryo does not show a particular gender at all
At week 7 till week 20, embryo under a series of changes until a male or female phenotype is recognized

Gonads become ovaries or, in the case of the male, the testis
The primary genital duct that develops in the male is Mesonephric duct (Think M= male)

Scrotum:
In 3rd week, mesenchyme cells in primitive streak –>go to cloacal membrane to form cloacal folds

• Cranial (towards the head side, ant) to the cloacal membrane, the cloacal folds form genital tubercle
• Caudally, cloacal folds become urethral folds ant, and anal folds post

On each side of urethral folds, genital swellings form –> later form scrotal swelling in male, labia majora in female

• genital swellings grow in inguinal region, move caudally
• each makes up one half of scrotum, separated by scrotal septum

Testis:

1. intermediate mesoderm forms longitudinal elevation along dorsal body wall = urogenital ridge
2. coelemic epith + underlying mesoderm cells proliferate = from gonadal ridge
3. Primary sex cords from gonadal ridge and absorb primordial germ cells from primitive yolk sac –> later regress, but do form seminiferous tubules, tubuli recti, rete testis
4. lose connection w/ surface epithelium as tunica albuginea forms there

In order for males to become males, they have a specific gene = TDF, or testis determining factor

Seminiferous cords have the primordial germ cells and Sertoli cells - that secret MIF (Mullerian inhibiting factor), that supresses the development of the primary genital duct in female = the paramesonephric duct or mullerian duct.

Mesoderm b/w seminiferous cords –> give Leydig cells that secrete testosterone
Mesoderm = Leydig, Sertoli cells, primordial germ cells, and CT stroma of testis

Seminiferious cords canalize and form into tubules during puberty

Descent of Testis:

• All of the above reactions occur w/in the abdominal cavity
• Testis have to descend into scrotal sac
• It is unknown what makes them do so – but it seems to be related to growth to ab viscera, the gubernaculum, and testosterone

gubernaculum descends w/ testis in inguinal canal, and remnants of it hold the testis w/in the scrotum in adult life

Peritoneum also follows testis into scrotal sac via inguinal canal, and form the tunica processus vaginalis –> become the parietal and visceral layers of tunica vaginalis

Genital Duct formation:
Paramesonephric duct starts to develop, but later regresses, due to MIF

Mesonephric duct forms = epididymis, ductus deferens, seminal vesicle, ejaculatory duct, efferent ducts of testis

Anatomy:The anatomy of  the female external genital organs.

Vulva (female external genital organs)

Similar to male genital organs except:

• vagina pierces UG diaphragm
• urethra associates w/ ant wall of vagina
• genital folds do not unite @ midline –> instead forms vestibule
• bulbus does not unite @ midline

Vulva is made up of:

1. mons pubis
2. labia majora
3. labia minor
4. clitoris
5. vestibule
6. bulbus vestibuli
7. greater vestibular glands
8. vaginal orifice
9. ext. urethral orifice

Mons Pubis:

• rounded elevation of pubic area above symphysis
• subcutaenous CT – inc @ puberty, dec w/ menopause
• covered w/ pubic hair = secondary sexual sign (maturity)

Labia Majora:

• external covering of the vestibule
• contain fat as well, and smooth m bundles
  
• also covered w/ hair
• L & R join @ ant/post commissure – post usually disappears after having a child
  
• bulb of vestibule and glands below them
• round ligament inserts here after emerging from inguinal canal
• outer surface is covered w/ pigmented skin w/ many sebaceous glands
  

Labia Minora:

• small hairless folds w/in labia minora
• enclose the vestibule directly
• united posteriorly via frenulum of labia minora, clitoris
  
• unites ant to form prepuce of clitoris
• contain bulbospongiosus m
• high # of nerve endings = primary erogenic organ

Clitoris (homologus to male penis)
a) Root

• crura of clitoris originate from inf ramus of pubis
• ischiocavernosus m covers the crura
• L & R crus join @ midline and angle down to form body

b) Body

• suspended from pubis symphysis via suspensory ligament
• made from union of corpora cavernosa

c) Glans

• made from corpora cavernosum
• under cover of prepuce when flaccid
• protrudes when erected
• rich in n endings –> stimulate for orgasm

Vestibule

• space enclosed by labia minora
• has ext urethral orifice
• openings of paraurethral glands
  
• contains openings of vagina, urethra, and greater vestibular glands

Bulbus vestibuli (analogous to bulb of penis, corpus spongiosum)

• don’t unite @ midline
• separated by vagina
• become erect during sexual excitement = erectile tissue
  
• open labia minora
• bulbospongiosus m. covers bulb

Vaginal orifice

• located @ post part of vestibule
• behind ext opening of urethra
• Hymen closes off vaginal opening, leaves an opening, breaks during 1st sexual intercourse

Ext urethral orifice

• small opening @ ant part of vestibule
• just in front of ant wall of vagina
• 2-3 cm post to clitoris
• contains ducts of paraurethral glands (analogous to prostate) – will secrete the female ejaculate
  

Greater vestibular glands

• @ post end of bulb of vestibule
• behind vaginal orifice
• open @ side of labia minora
• secrete lubricant (mucus) during sexual excitement
• also surrounded by bulbospongiosus m
  
• lubricate vaginal orifice for penetration

Blood supply:

• ext pudendal a (femoral a) – supplies skin
• int pudendal a (int iliac a) – skin , sexual organs, perineal muscle
  
  • labial a
  • deep dorsal a of  clitoris
    
• drained by int pudendal v

Lymph Drainaga: superficial inguinal lymph nodes

Nerve supply:

• Ilioinguinal n (lumbar plexus)
• genital br of genitofemoral n (lumbar plexus)
• pudendal n
• cut br of femoral n

PNS = inc vaginal secretion, excitation of clitoris, erection for tissue in bulbs of vestibule

Vagina:

Function = organ of copulation & birth

• excretory duct for menstrual blood
• inf part of birth canal
• participates in sexual intercourse

General Info:

• runs  from cervix of uterus –> vestibule
• 7-9 cm, usually flat
• has transverse folds, which flatten during sex to accomadate penis = rugae
• 30-40 degrees back from vertical plane
• opens into vestibule of vulva
• opening partially closed off by hymen

• upper end divided into 4 fornices = 1 ant, 1 post, 2 lat that surround vaginal portion of cervix
  • ant fornix = shallowest, touches fundus of bladder
  • post fornix = deepest and touches rectouterine pouch, covered w/ peritoneum of rectum post
  • lat fornix = uterus, uterine a/v – w/in broad lig of uterus

Various Views of Vagina - Topography, internal structure, etc

Topography:

• ant = urethra in urethrovaginal septum, space b/w vagina and septum = urethrovaginal space
• post = loops of SI (sup), rectum via rectovaginal septum
• lat = contact cervix of uterus (sup)
• inf = levator ani m, UG diaphragm, perineal body

supported by:

• upper part = levator ani m, transverse cervical lig, pubocervical lig, sacrocervical lig
  
  • (ligaments together = paracolpium of vagina)
  • fibers merge w/ fibers of paraproctium(post) and paracysticum (ant)
• middle part = UG diaphragm
• lower part = perineal body

Blood supply:

• vaginal a (uterine a)
• vaginal br of int pudendal a (inf part of vagina), middle rectal a (middle part of vaginal), int iliac a

Venous drainage = vaginal venous plexus –> pelvic venous plexus –> int iliac v

Lymph Drainage:

• Sup part = int/ext  iliac l.n.
• Mid part = int iliac l.n
• Inf part = sacra and common iliacn l.n., superficial inguinal l.n.
  

Nerve supply: for autonomic innervation see topic # 40

• Inf hypogastric plexus
• pelvic splanchnic n

Minimals for this topic:

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208. Define the visceral relations of the vagina?

• The vagina is related anteriorly to the uterus and bladder and is fused with the urethra. Posteriorly, the vagina is related to the recto-uterine pouch, the rectum and the perineal body. The lateral fornix of the vagina is related to the ureter and uterine artery. At its upper aspect the vagina fuses with the uterus, so that it encloses the vaginal part of the cervix.

Slide #75 Vagina *H&E

Stuctures to Identify:

• str squamous non keratinized epithelium
• LP
• 2 muscular layers
• adventia, with n/possible ganglia and sk. musc

* So if you see a thick epithelium that fades from pink to white as u move up = VAGINA

General Info:

• no glands here – all lubrication done by cervical glands and Bartholin’s glands at entrance
• epithelium thickens and secretes glycogen under influence of estrogen
• Vaginal bacteria changes the glycogen into lactic acid — acidity protects the vaginal canal from pathogens

Epith

• is very characteristic of vagina
  
• THICK,  str squamous epithelium  with mucosal folds
• has Langerhan’s cells @ base
  
• CT papilla coming up from under lying LP
• very faint because very rich in glycogen, which can be washed away in slide prep.
  

Vaginal pale epithelium, notice the lymphocytes and Langerhan's cells at base of epith, as well as CT papilla

LP

• aka semi cavernous tissue = b/c a/v similar to cavernous tissue of penis
• dense reg CT filled with elastic tissue for stretching of vaginal wall
• MALT, lymph nodules, a/v
• underlying submucosa interweaves with it
• no definitve border between LP and submucosa = NO muscularis mucosae

Muscular Layer

• Inner longitudinal layer, outer oblique layer

Adventia

• lots of a/v and n bundles
• may have PNS ggl
• May have skeletal m fibers from perineal m – not part of vagina, just attached to wall of it

Anatomy of Uterus/Uterine Tube

Uterus:

Location: b/w bladder (ant) and rectum (post), above and leads to vagina

Function: Major organ of gestation

General Info:
7-8 cm long, 5-7 cm wide, 2-3 cm wide
2 main parts = corpus (upper 2/3) and cervix (lower 1/3) , connected via isthmus

• Cervix protrudes into vagina @ angle of 60-70 degress = anteversion ( angle b/w vagina and cervical canal)
• Body inclines forward and bends over fundus of bladder, attached to cervix w/ angle of another 60 degrees = anteflexion ( angle b/w jxn of cervix and body)

Topography:

• ant = fundus of bladder
• post = coils of SI, and via pouch of Douglas, the rectum
• lat = cardinal ligament @ level of cervix (part of parametrium), that carries the uterine a/v
• sup = fundus of uterus touches SI coils
• inf = supported by pelvic diaphragm, UG diaphragm, round, broad, lateral cervical ligaments, pubovesical, sacrocervical, retro-uterine ligaments

Parts:

Cervical portion:
has 2 areas:
Vaginal portion – protrudes into vagina,surrounded by vaginal fornices

• has rounded end and ext os of uterine canal w/in it
• @ ext os, simple columnar epith –> str squamous
  
• If no kids (nulliparous) – opening is round, and small
• If kids (multiparous) – opening is slit like

Supravaginal portion – embedded into CT of visceral pelvic fascia (via parametrium), in direct contact w/ broad ligament (myometrium)

Cervical Canal:

• terminal portion of uterine cavity
• has impermeable plug of mucus,
  • helps prevent entrance of pathogens
    
  • that becomes permeable during ovulation –
  • does allow sperm to penetrate
• b/w cervix and isthmus of uterus = int histological os – where wall of cervix changes to uterus histologically

Epith of cervix isn’t shed in menstruation like the epith of rest of uterus = simple columnar, # of glands inc in this area – they secret the mucus to make mucus plug
keeps closed until few hours before birth – then begins to dilate to allow head thru – this is due to high amt of collagen and smooth M in cervix

Cervix doesn’t have real myometrium, called it, but really has less smooth m and more elastic fibers compared to rest of uterus

NOTE: (Please do not be confused by the 50 names out there for the same thing)

• Int opening of isthmic canal = anatomical int os (does not exist in pregnancy)
• Int opening of uterus = int os = histological int os = external opening of isthmus (isthmic canal)
• Ext opening of uterus = external os

Corpus

Biggest part of uterus
covered by broad ligament = called the mesometrium of uterus, attaches it to lateral body wall
bends over the bladder (ant)

Has two special parts : fundus & isthmus
Fundus

• area above the level of uterine tubes
• laterally, ends in uterine horns –> lead to uterine tube

Isthmus

• narrow part locared b/w cervix & corpus of uterus
• same histological structures as corpus of uterus
• incorporated into cavity of uterus during pregnancy – @ 2nd 1/2 of pregnancy, isthmus opens up, so anat int os ceases to exist, only histo os and ext os still there
  
• isthmic canal – canal w/in the isthmus
• Int anatomical os – b/w isthmic canal and uterine cavity

Wall of Uterus
Perimetrium = outer layer, peritoneum & underlying subserosa
Myometrium = middle musc layer, has sublayers
Endometrium = innermost layer, layer removed during menstruation

Ligaments of Female Pelvis

1. Broad ligament of uterus - 2 layers of peritoneal covering, from lat margin of uterus –> lat pelvic wall
   • holds uterus in position
   • contains: uterine tube, a/v, round ligament, ovarian ligament proper, urete, uterovaginal n. plexus, lymph vessels
2. Mesovarium - fold of peritoneum that connects ant surface of ovary w/ post layer of broad ligament
3. Mesosalpinx – fold of broad ligament that suspends the uterine tube
4. Mesometrium-  fold of broad lig below mesosalpinx, and meso-ovarium, lat wall of uterus –> pelvic wall
   
5. Proper Ovarian ligament – fibromusc cord from uterine end of ovary –> side of uterus below uterine tube w/in broad lig
6. Suspensory ligament of ovary – band of peritoneum that runs sup/lat from end of ovary –> pelvic wall, has ovarian a/v, lymph vessels
7. Lat/Transverse Cervical (Cardinal) Lig of Uterus (aka ligament of Mackenrodt’s) – fibromuscular condensations of pelvic fascia from cervix (hence, cervical) & lat fornix of vagina –> pelvic wall, run w/in parametrium of uterus
8. Parametrium – fibrous CT that runs w/in mesometrium, connects uterus to lat pelvic wall
9. Paracolpium – fibrous CT that connects the lat wall of vagina –> lat pelvic wall, fibers merge w/ those of para cysticum (for bladder)
10. Pubocervical ligament – firm bands of CT from post surface of pubis –> cervix of uterus
11. Sacrocervical(uterine) ligament – firm fibromuscular bands of pelvic fascia from lower end of sacrum –> to cervix, upper end of vagina *palpable in rectal exam
12. Pubovesical ligament – pelvic fascia bands from neck of bladder (or prostate in male) –> pelvic bone
13. Rectouterine ligament – holds cervis back and up and sometimes elevate a shelf-like fold of pertioneum (recto-uterine folds – called sacro-genital folds in male)
    • isthmus of uterus –> post wall of pelvis, lat to rectum

Ligament relations of Uterus & Uterine tube

Connective tissue ligaments of female pelvis

Also, peritoneal covering over pelvic organs in female create 2 pouches:
1. Vesicouterine Pouch

• ant = bladder
• post = uterus
• lat = vesicouterine folds

2. Rectouterine pouch – aka Douglas pouch

• ant = uterus
• post = rectum
• lat = rectouterine folds
• floor = post fornix of vagina, in direct contact w/ ampulla of rectum *can be felt there via rectal exam

CLINICAL NOTE: This is deepest point of peritoneal cavity in female, any excess peritoneal fluid will collect there
blood in pouch can indicate the presence of ectopic pregnancy

Pouces and ligaments/Topography of Female Pelvis

Blood Supply: primarily uterine a, secondarily ovarian a

• Uterine a enters parametrium via cardinal ligament of ovary
  • when it reaches isthmus, divides into large asc uterine br
  • small desc uterine br
  • also has ovarian and tubal br
  • @ cardinal lig  – uterine a/v crosses ureter and have vessels in fromt
• Ovarian a
  • has ovarian and tubal br that anastomose w/ same br of uterine a
• Veins = uterovaginal plexus of veins –> int/ext iliac v

Blood Supply of Uterus, Uterine tube

Lymph Drainage:
1. Fundic region = aortic nodes via ovarian lymph vessels
2. Corpus = ext iliac and sup inguinal nodes
3. Cervix = int iliac and sacral nodes

Nerve Supply = branches of hypogastric n plexus,

Uterine Tube:
non united part of Mullerian duct (embryo)
Location: from horn of uterus –> ends in ampulla @ uterine end of ovaries

Function:

• carries fertilized or unfertilized ovum from ovary to uterus, for Implantation
• via action of the cilia on its epithelium, and contraction of musc wall, also carries sperm towards the ovary
• Connects uterine cavity w/ peritoneal cavity
• Fertilization occurs in ampulla or infundibulum of uterine tube

Parts:
1. Infundibulum – funnel-shaped distal portion over end of ovary

• has 20-30 fimbriae, which attach to ovary
• move to guide oocyte in after ovulation
• communicates w/ peritoneal cavity via abdominal ostium

2. Ambulla – FERTILIZATION

• widest and longest part of uterine tube
• INTRAPERITONEAL
• attached w/in broad ligament via mesosalpinx

3. Isthmus – short 2.5 cm long area that leads to horn of uterus

4. Uterine part

• part that attaches to uterine wall
• opens into uterine cavity via  uterine ostium

Blood supply = tubal br of ovarian and uterine a, veins run w/ a

Lymph drainage = run to aortic/lumbar nodes

Nerve supply = pelvic/ovarian n. plexus, that run in mesosalpinx

Minimals related to this topic:

196.    Describe the relation of the ovary to the uterine tube!
The upper or tubal end of the ovary is closely related to the uterine tube. The infundibulum has irregular fringes called fimbriae that project from the margin of the infundibulum to the ovary.
197.    Define the term “broad ligament of the uterus” and list those structures that are located within its substance!
A double layered peritoneal ligament extending from the sides of the uterus to the lateral walls and the floor of the pelvis.
Structures: uterine tube, round lig. of uterus, ovarian lig., epoophoron, paroophoron, uterine vessels, uterovaginal venous plexus, nerves.

198.    Define the term “parametrium”!
The loose connective tissue found between the two diverging layers of the broad ligament of uterus, which connects the lateral part of the cervix with the pelvic wall.
199.    Define the position of the uterus under normal conditions?
In the axis of the true pelvic, in anteflexion (bends forward) and anterversion (inclines forward)

200.    Define the term anteflexion and anteversion of the uterus!
Anteversion: the cervix is inclined anteriorly at an acute angle (appr. 60°-70°) to the vagina.
Anteflexion: the body of the uterus is bent anteriorly at an acute angle (appr. 60’-70’) to the cervix.

201.    Describe visceral relations of the uterus!
anterior    : posterior wall of bladder,
posterior    : anterior surface of rectum, small intestines,
above    : small intestines,
lateral    : ureter, before its opening into the urinary bladder.

202.    What is the epithelium of the a.) cervical canal and b.) vaginal portion of the uterus?
simple columnar mucous producing epithelium, with scatterd ciliated cells,
stratified squamous non keratinizing epithelium.

203.    Describe the peritoneal relations of the uterus!
The body and the posterior aspect of the supravaginal portion of the cervix is enclosed between the two layers of the broad ligament. The peritoneum reflects from the uterus posteriorly to the rectum and anteriorly to the urinary bladder forming the rectouterine and vesicouterine pouches, respectively.

204.    Define the term “Douglas pouch”?
Rectouterine pouch. Reflection of the peritoneum from the rectum to the uterus. The deepest point of the peritoneal cavity.

205.    List those structures that help to fix the uterus in its original position!
Vagina, pelvic and urogenital diaphragms, round lig., ovarian lig., vesicouterine fold, rectouterine fold, thickenings of the visceral pelvic fascia, broad lig., parametrium.

206.    Which lymph nodes receive lymph from the a.) fundus, b.) body and c.) cervix of the uterus?
aortc, external iliac, superficial inguinal lymph nodes,
external iliac lymph nodes,
internal iliac and sacral lymph nodes.

Histology of Uterus/Uterine Tube

Slide #76 Uterus, Proliferative phase

Structures to Identify:

• all layers of wall
• simple columnar lining epithelium
• simple tubular glands
• a/v – arteries have a fused tunica mucosa
• LP w/ spinocellular CT

General Info:

• Endometrium (same as mucosa) changes with menstrual cycle
• Menstrual cycle
  • Day 1-5 = Menstruation
  • Day 5-6 Regeneration
  • Day 6-14 Proliferative/Estrogen phase
  • Day 14-28 Secretory/Progesterone/Luteal phase
• Uterus provides the site of implantation of fertilized embryo and formation for placenta
• Note that the embryo grows within the wall of the uterus, causing the lumen to narrow, and forms a separate amniotic sac – the embryo does not grow in uterus lumen per se.

Endometrium

• innermost layer, is equivalent to mucosa in other slides
• changes made in endometrium based on hormones produced by ovaries
• To tell that it is Uterus look for: v THICK mucosa, with loads of glands, and is very basophillic

Epith

• simple columnar epith (ciliated and non ciliated cells)
• epith is lower because this is the start of the cycle
• non-ciliated cells will secret hormones in second part of cycle

LP

• cell rich CT highly vascularized
• simple tubular glands – inactive in this  stage
• b/w glands, spinocellular CT & a/v
  • the endometrial stroma, which resembles mesenchyme
    
  • is highly cellular+ contains abundant intercellular ground substance.
  • cells  = stromal cells like in ovary
• thickness depends on stage in cycle
• Has two layers = Statum Functionalis superiorly, and Stratum Basalis inferiorly
• Blood Supply:
  • RADIAL ARTERIES, (branches from the arcuate arteries in myometrium), enter the basal layer of the endometrium, where it give off small straight arteries that supply this region of the endometrium.
  • The main branches of the radial artery continous upward, become highly coiled SPIRAL ARTERY
  • Spiral arteries give off numerous arterioles, that often anastomoses, as they supply a rich capillary bed.
  • Lacuna= dilated segmants, may also occur in the venous system, that drains the endometrium.
  • The straight arteries+ the proximal part of the spiral arteries do not change during the menstrual circle.
  • The distal portion of the spiral ateries undergoes degeneration+ regeneration, with each menstrual cycle, under the influence of estrogen+ progesteron.

Note the smooth and oval glands in the endothelium = def proliferative phase uterus

Stratum Functionalis

• the one that proliferate+ degenerate during menstrual cycle
• during this phase of the menstrual cycle, the endometrium varies from 1 to 6 mm in thickness.
• UTERINE GLANDS(simple tubular): surface epithelium invaginate into the underlying lamina propria, the endometrial stroma.
• containing fewer ciliated cells
• If the glands are oval and smooth in the section, then you know it is proliferative stage.
  
• Separated into upper Compact Layer, and inner Spongy layer
  

Stratum Basalis

• minimal changes in the is layer between stages in the uterus
• regeneration of epithelium starts from the stromal cells and glands in this layer
• large amount of cells int his layer – even more so than in basal layer

NO MUSC MUCOSA/ SUBMUCOSA separate the endometrium from the myometrium.

Myometrium

• is the thickest layer of the uterine wall

• composed of 3 undefined layers of smooth muscle bundles: you see cross, oblique, longitudinal sections.

• the smooth muscle bundles in the inner+ outer layers are predominantly oriented parallel to the long axis of the uterus.

• muscle separated by interstitial CT
• lots of a/v. —> tunica media of arteries merges with smooth m of the myometrium
• arcuate a in myometrium =  vascular zone
  • separates the uteine wall into three zones – Supra vascular, vascular, and perivascular below.

  • 6- 10 arcuate arteries coming from the uterine artery that anastomose in the myometrium

Perimetrium

• adventia/serosa
• on sup surface of uterus, covered with peritoneum –> serosa
• In other surfaces of uterus, is infraperitoneal –> covered with  adventia
• If adventia, can possibly see ggl cells and nerve cells
  

PROLIEFERATING PHASE REGULATED BY  ESTROGEN:

• at the end of the menstrual phase, the endometrium consits of a thin band of CT(about 1 mm) thick, containing the basal portion of the uterine gland+lower portion of the spiral arteries. = stratum basale the layer, that was sloughed off was the stratum functionale.
• Stromal, endothelial+ epithelial cells in the stratum basale proliferate rapidly, following changes can be seen:
• Epithelial cells in the basal portion of the glands reconstitute the glands &  migrate to cover the denuded endometrial surface.
• Stromal cells:  proliferate, secrete collagen, & ground substance
• Spiral arteries lenghten, as the endometrium is reestablished, these arteries are only slightly coiled+ do not extend into the upper third of the endometrium.
• Continous until 1 day after ovulation, which occurs at about day 14, of a 28- day cycle.
• At the end of this phase, the endometrium has reached a thickness of about 3 mm.
• The glands have narrow lumina+ relatively straight, but have a slightly wavy appearance.
• Accumulation of glycogen are present in the basal portion of the epithelial cells.

Slide #77 Uterus, Secretory phase

See the white space between the cells of stroma? And the twisted glands? = Secretory Phase Uterus

Structures are the same as listed above, with some key differences

Endometrium

• Stratum functionalis -
  
  • MUCH thicker,
    
  • uterine glands are now larger and wavy, not oval shaped –> increase size due to secretion within
    
    • inside of glands are pale because secretions are mostly carbs
      
  • arteries are also more coiled , and become more prominent in this layer
    • increase in volume, to prepare for menstruation, the next phase
      
• Stratum basalis -
  
  • less cells in interstitial tissue, more white space between cell
  • the increased interstitial fluid between the cells is called Interstitial EDEMA
  • more WBC, monocytes, neutrophils, granulocytes
  • straight a in this layer —> coiled arteries in fuctional layer
• Stromal cells become decidual cells –> preperation for formation of placenta
  

Myometrium

• more smooth m fibers

SECRETORY PHASE IS REGULATED BY PROGESTERON

• The stimulation for transformation is the implantation of the blastocyst.
• Large, pale cells rich in glygogen result from this transformation,
• they create a specialized layer that facilitates the seperation of the placenta from the uterine wall at the termination of pregnancy.

Menstrual phase *Dont need to know for test, just theory to understand *

• results from a decline in the ovariation secretion of progesterone+ estrogen

• CORPUS LUTEUM produces hormones for about 10 days if fertilization does not occur.
• As hormone levels rapidly decline, changes occur in the blood supply to the stratum functionale.
• Periodic contractions of the walls of the spiral arteries, lasting for several hours, cause the stratum functionale.

Periodic conctraction of the walls of the spiral arteries, lasting for several hours stratum functionale to become ischemic.

• Glands stop secreting+ the endometrium shrinks in heigh as the stroma becomes less edematous.
• After about 2 days, extended periods of arterial contraction, with only brief periods of blood flow, cause disruption of the surface epithelium+ rupture of the blood vessels.
• When spiral arteries close off, blood flows into the stratum basale, but not in the stratum functionale.
• Blood, uterine fluid+ sloughing stromal+ epithelial cells from the stratum functionale constitute the vaginal discharge.
• As patches of tissue separate from the endometrium, the torn ends of veins, arteries+ glands are exposed.
• In the absence of fertilization, cessation of bleeding would accompany the growth+ maturation of new ovarian follicels.
• The epithelial cells would rapidly proliferate+ migrate to restore the surface epithelium as the proliferative phase of the next cycle begins.
• In the absence of ovulation( a cycle refered to as an anovulatory cycle), a corpus luteum does not form, and progesterone is not produced.
• In the absence of progesterone, the endometrium does not enter the secretory phase until menstruation.

Slide #76 Uterus, Pregnant * H&E

Structures to Identify

• endometrium with glands = decidua basalis
• myometrium
• chroion frondosum (primary villi)
• embryonic cavity
• primary, secondary, tertiary villi
• chorion leave
• decidua capsularis, marginalis, parietalis
• a/v

General Info:

This slide is not as difficult as it may seem.  Look at the picture to the right to first familairize yourself with the layers listed.

First look for a long white tube with a thick wavy over covering –> this is the embryonic (amniotic) cavity.

• On one side of it is chorion frondosum, with all the villi inside
• Villi contain fetal blood
  • between the villi is the intervillus space that houses maternal blood
• lateral to the chorion frondosum, is decidua basalis
• on the other side of the amniotic cavity, is the chorion laeve, with the decidua capsularis lateral to that.

Villi

• Villi are projections from the decidua that house branches of the uterine a/v, and contain fetal blood
• they project into the space between the decidual layers.
• maternal blood surrounds them in intervillous space
• Free gas exchange occurs between the villi and intervillous space
• 2 types of villi: anchoring villi (attached to chorion), floating villi (free floating)
• made from trophoblast cells – which makes two layers of cells – syncytiotrophoblast (outer) & cytotrophoblast (inner)
  
• Primary villus
  • 2 layers of trophoblast cells only
• Secondary villus
  • 2 layers with extra embryonic mesoderm in w/in
  • light center - look for white space in center
  • may have small a/b near the center
• Tertiary villus
  • the largest ones
  • only syncytiotrophoblast layer, much bigger, with a/v near periphery

Slide #74 Uterine Tube * H&E

Labyrinth like lumen of Uterine tube

Structures to Identify:

• simple columnar epithelium
• peg cells (right ovulation, might not be there)
• LP
• muscular layer
• a/v
• mesothelium (cells of perimetrium)
• adipocytes

Lumen: very labyrinth like – looks like a fern

• protrusion into lumens from mucosa
• amt of labyrinth depends  on location where section was taken –> less in infudibulum, more closer to uterus
• Do NOT confuse with Prostate. The folds look similar, but there are no prostatic calcifications, and there is only one lumen here, not a bunch of small fuzzy tubules
• 
• Epith and LP of Uterine Tube, with ciliated and peg cells shown

Epith

• simple columnar epithelium – do NOT say psuedo stratified
• some cells ciliated
  • these are shorter and have less cilia at times,
  • After ovulation , are taller with more cilia,
  • depending on hormones released in ovarian cycle (estrogen)
• thickness changes w/ menstrual cycle
• the non ciliated cells = peg cells
  • secrete mucin = carbs for sperm
    
  • expelled from epith when dead (die after excreting their mucin)
  • project into lumen
  • look like nails
  • look for long cells in a bump on top of epith
• During proliferative phase of uterus, with increase amount of estrogen, the cilated cells become larger and have more ciliae – peg cells secret more mucin

L.P.

• loose CT, with a/v
• numerous fibroblasts with collagen and reticular fiber
• supports the CT papilla projections into the mucosa

No Musc. mucosae or Submucosa

Muscular coat (Musc ext)

• inner ciruclar, outer longitudinal layers
• more developed closer to uterus
• has PNS ggl/nfibers – may be able to find them

Outer coat = serosa

• made of double layer of broad ligament with a/v inside
• made of mesothelial cells
• has a/v + adipocytes
  

Embrology of Uterus/Uterine Tube

• PARAMESONEPHRIC DUCTS  develop into the MAIN GENITAL DUCTS OF THE FEMALE.

• 3 parts can be recognized in each duct:

  • a cranial vertical portion that opens into the abdominal cavity

  • a horizontal part that crosses the mesonephric duct

  • a caudal vertical part that fuses with its partner from the opposite side.

• With descent of the ovary, the first 2 parts develop into the uterine tube+ the caudal parts fuse, to form the uterine canal.

• When the second part of the paramesonephric ducts moves mediocaudally, the urogenital ridges gradually come to lie in a transverse plane.

• DUCTS fuse in the midline, a broad transverse pelvic fold is established.

• BROAD LIGAMENT OF THE UTERUS: fold, which extends from the lateral sides of the fused paramesonephric ducts toward the wall of the pelvis.

• The uterine tube lies in its upper border, and the ovary lies on its post. Surface.

• UTERORECTAL POUCH+ UTEROVESICAL POUCH are devided by the uterus+ broad ligaments

• CORPUS+ CERVIX of the uterus coming from the fused paramesonephric ducts.

• MYOMETRIUM(= muscular coat of the uterus)+ Peritoneal covering(perimetrium) = layer of mesenchyme

Anatomy of Ovary

* only structure in ab/pelvis cavity that is EXTRA PERITONEAL

General Info:
surface covered w. germinal epithelium, which is modified peritoneal covering from development

Location: in ovarian fossa, in post part of broad ligament, @ lat wall of pelvis, located @ bifurcation point of common iliac a on both sides, @sacro-iliac joint

Topography:

• ant = med umbilical ligament
• post = ureter & int iliac a
• sup extremity = infundibulum of uterine tube, end suspended via suspensory ligament of ovary (contains ovarian a/v) = highest point of broad ligament
• inf extremity = angle of body, uterine tube via proper ligament of ovary (analogous to guberlaculum testis)

Peritoneal relations:

• connects to post side of broad ligament via mesovarium
• NOT covered w/ peritoneum, so ovum can fall into peritoneal cavity –> fallopian tube
• CLINICAL NOTE – if somehow fertilized outside of uterine tube, can cause ectopic pregnancy

• • The ovary is anchored to the posterior aspect of the broad ligament by a peritoneal fold, the mesovary.

  • The suspensory ligament of the ovary extends from the tubal end of ovary to the lateral wall of the pelvis. It contains the ovarian blood vessels and nerves.

• Farre line: a whitish line marking the insertion of the mesovarium at the hilum of the ovary.
  

Blood Supply: ovarian a (contained w/in suspensory ligament of ovary)
has ovarian and tubal br that make anatomosis w/ ovarian br/tubal br of uterine a

Venous drainage:

• veins draining ovary make a pampiniform plexus (like the one around the testis), that run w/in broad ligament
• Ovarian v – R –> IVC
• L –> L renal v

Lymph drainage: vessels follow ovarian a/v and join vessels from uterine tube and fundus of uterus –> lumbar lymph plexus

Nerve Supply:

• SNS and aff fibers –> run w/ ovarian a/v —> make connections w/ pelvic plexus –> ovarian n plexus
• PNS: from pelvis splanchnic n –> same route w/ ovarian vessels

Histology of Ovary

Slide #72 Ovary *H&E

Structures to Identify:

• primoridal follicle
• germinal epithelium
• primary follcile
• secondary follicle
• tertiary (grafiaan) follicle
• corpus luteum
• corpus hemorroidal
• corpus fibricans
• corpus albicans
• cumulus oophorus
• corona radiata
• zona pellucida
• theca internta
• theca externa
• granulosal cells
• stromal tissue (spino cellular tissue)

General Info

• 2 major functions = production of gamete (oocytes), production of hormones (progesterone, estrogen)
• has tubular pole – connected to suspensory ligament
• has uterine pole – connect to uterus via proper ligament of ovary
• External cortex – site of follicular maturation
• Internal medulla – rich in CT, lymph, a/v

Function:Hormone secretion = corpus luteum responsible for Steroidogenesis
1. Estrogen – promotes maturation of internal and externa genitalia, and development of mammary gland
2. Progesterone – prepare uterus for pregnancy, and mammary gland for lactation.
Both hormones play key role in menstrual cycle

Cortex

• Epith = cuboidal germinal epithelium, instead of mesothelium,
  • Therefore,  in case of ovulation, rupture of epith is possible to release oocyte.
  • The epith can grow and cover the rupture hole.
  • Repeated rupturing due to monthly ovulation of a woman leads to a scarred look on the epith.
  • There is  no mesothelium coverage, because ovary is EXTRAperitoneal, though is continuous with mesothelium of visceral peritoneum of surrounding areas.

• Beneath that is a layer of dense CT = tunica albuginea.
• Then is the stromal or spinocellular tissue, in which all the follicles are embedded
  • also just called stroma
  • contains fibrocytes and smooth m cells, that contribute to theca externa

Stages of Follicle Maturation: – find follicles within the cortex.

follicular development

• process beings with premordial follicle and ends with ovulation of oocyte into uterine tube
• occurs under influence of FSH
• In fetal life, oocytes divid mitotically, creating HUGE # of oogonia (not so in life)
• As female goes thru puberty, ovaries begin process of reproductive activity  characterized by  growth and maturation of oocytes and surrounding follicles, meaning that the size of follicles can te4sll how close we are to creating mature oocyte.

Primoridal follicle: – make about 20/month.

• oocyte surrounded by single layer of follicular cells,
• simple squamous epith
• resting in prophase

primordial follicle

1st Primary follicle

• follicular cells enlarge and become cuboidal = now called granulosa cells,these cells later form the corona radiata
• zona pellucida starts to appear – non cellular layer between corona and oocyte itself
  • Glycoprotein rich zone (ZP 1, 2, 3 )
  • Zone of contact and communication between oocyte microvilli and granulosa cell processes.
  • Develop gap junctions
• oocyte itself becomes bigger

primary follicle

2nd primary follicle -

• zona pellucida is present (very eosinophillic, made of carbs, can be stained by PAS)
• follicular epith become stratified and becomes known as stroma granulosum.
• Theca cells from surrounding CT begin to be seen. These are actually stromal cells layering themselves into two layers

Seconday follicle -

secondary follicle

• Clear theca interna and externa seen, zona pellucida seen
• antrum vacuoles start to appear
  • with follicular liquor inside, that contains peptides produced by granulosa cells
  • if u see an antrum = secondary follicle
• granulosa cells on one side of follicle surrounds the oocyte to form = cumulus oophorus
• Between layer of granulosa cells and theca cells is a thin basement membrane
• Theca internata is thicker and very defined inner layer –> produces hormones
• Theca externa is much thinner and interweaves with surrounding CT

Tertiary follicle = Graafian follicle

• Largest ones in slide, usualy closer to center of slide
• theca interna  and theca externa are thicker
• cresent shapen antrum is now seen (formed by merging of previously seen vacuoles)
• corona radiata (communicates with gap junctions)
• oval within inter cavity, with liquid inside
• oocyte accentric within follicle (attached to one side)
• granular cells protrude into cavity to produce the cumulus oophorus.

Remember that the corona radiata accompanies oocytes in ovulation, as well as the zona pellucida.

Within follicle, seconday oocyte has 1 cm diameter.

Maturation of follicles are activated by FSH (Follicular stimulating hormone), EGF (Epidermal Growth Factor), and Ca2+

Oocyte stops growing thanks to OMI (Oocyte Maturation Inhibitor), secreted by the granulosa cells.

Oocyte maturation

• Oocytes stay in primary follicle phase for 15-20 years in prophase I of 1st Meiotic division
• Completion of 1st stage of Meiosis occurs only before the ovulation in the Graafian follicle.
• Primary oocyte (4n) splits into –> Secondary oocyte + 1st polar body
• Secondary oocyte is arrested in metaphase of 2nd meiotic division
• completed only if seconday oocyte is penetrated by spermatogonia, in which case the seondary oocyte –> final oocyte + 2nd polar body

Fertilization (discussed in more detail in another topic)

• Occurs in ampulla of uterine tube – secondary oocyte and sperm meet
• Before this, capacitation occurs to spermatozoa, allowing to bind to receptors on zona pellucida
• By binding to these receptors, acrosomal reaction of spermatozoa occurs, (enzyme release by cap of sperm to enable the sperm to penetrate the oocyte)
• Male pronucleus combine with female pronucleus –> zygote is formed

3 mechanisms to ensure only 1 sperm enters oocyte
Depolarization of Oolema
Cortical reaction
Zonal reaction

Medulla

• dense irregular CT, that is connected to the uterus via meso-ovary.
• has many a/v

Slide # 73 Ovary w/ Corpus Luteum

Unique structures to Identify:

• Granulosa lutein cells
• Theca lutein cells
• Follicular cavity
• CT
• a/v

General Info:

Follicular atresia – at any point of follicular development, it can degenerate and then be absorbed via phagocytosis

• atretric cells can be seen through out cortex
• Early Stage:
  • theca interna and granulosa cells intact
  • some cells are in antrum within the follicular fluid
  • cumulus oophorus maybe be disrupted
  • oocyte starts to degenerate
  • BM is thicker and folded = glassy membrane
• Late Stage:
  • much smaller
  • stroma replaces follicular cells entirely
  • glassy membrane  is even thicker and folded

late follicular atresia

Corpus Luteum – formed after ovulation of a mature follicle and collapse of its wall

After ovulation, hemorrhage into the remains of the follicle usually occurs resulting in a structure called a corpus hemorrhagicum.  This transitory structure develops into a corpus luteum.

In most species LH from the pituitary gland initiates this luteinization and stimulates the granulosa cells to secrete progesterone.    The granulosa cells undergo hyperplasia (proliferation), hypertrophy (enlargement) and are transformed into granulosa lutein cells.   In several species, including the human, the accumulation of a yellow lipid pigment (lutein) and other lipids marks the transition to granulosa lutein cells.  The cells of the theca interna are also transformed into lipid-forming cells called theca lutein cells. The resulting structure is highly vascular.  If fertilization occurs, the corpus luteum persists and secretes progesterone.

If fertilization does not occur, the corpus luteum degenerates and is replaced by connective tissue forming a corpus albicans.

• theca lutein cells - formed from theca interna cells, located in periphery of corpus luteum, and w/it its fold
• granulosa lutein cells – hypertrophic granulosa cells (over grown)
• Theca externa CT pierces the walls of it.
• Later stage of it:
  • lutein cells shrink
  • pyknosis of the nuclei
  • fibrous center
  • CT replaces luteal cells  to form temporary fibrous capsule — eventually forms corpus albicans

Embryology of Ovary

Development of Ovaries:

• Intermediate mesoderm from longitudinal elevation along dorsal body wall = urogenital ridge
• coelomic epith & mesoderm of urogenital ridge proliferate = gonadal ridge
• Primary sex cords develop from gonadal ridge –> and absorb in primordial germ cells from yolk sac
  • Primary sex cords develop into rete ovarii – not there in adult life
• Secondary sex cords develop and absorb in primordial germ cells from yolk sac ,too
• –> break apart  into cell clusters = primordial follicles – that undergo FOLLICULAR DEVELOPMENT (see histo)

Mesoderm origin = primary oocytes, simple squamous lining, CT stroma of ovary

Descent of Ovaries:
all that was listed above occurs in abdominal cavity, and then descent into pelvic cavity
involves gubernaculum – a fibrous tissue that runs from:

• ab wall to end of ovary –> form ovarian ligament,
  
• and to labia majora –> form round ligament of uterus