32. The anatomy, histology and development of the uterine tube and uterus.

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

31. The anatomy, histology and development of the ovary.

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

16. Lymphatic dranaige of thoracic organs. The diaphragm. The histology of the skin. Implantation. Formation and differentiation of the trophoblast. Early phases of placentation.

16. Lymphatic dranaige of thoracic organs. The diaphragm. The histology of the skin. Implantation. Formation and differentiation of the trophoblast. Early phases of placentation.

Flash Cards:

Diaphragm 1

Anatomy: Lymphatic dranaige of thoracic organs. The diaphragm.

Lymph Drainage of Thoracic Organs:

Lung:

• superficial (subpleural) lymphatic plexus –  deep to visceral pleura, drain tissue of lung itself and visceral pleura –> bronchopulmonary l.n
• Deep lymph plexus (submucosal) – in submucosa of bronchi, and in peribronchial CT, drain structures that will go into root of lung  –> pulmonary l.n along bronchi –> broncho pulmonary l. n
• From bronchopulmonary l.n. –> sup/inf tracheobronchiol lymph nodes ( above/below bifurcation of trachea) –> R & L bronchomediastinal l.n. @ angulus venosus
• R bronchomediastinal l.n. –> R lymphatic duct
• L bronchomediastinal l.n. –> thoracic duct
• Lymph from parietal pleura –> nodes of thoracic wall ( IC, parasternal, mediastinal, phrenic l.n.), some near cupula pleura go to axillary l.n.

Lymph Drainage of heart:

• Lymph vessels in myocardium and subendocardial CT –> subepicardial lymph plexus –> coronary  groove & follow coronary a
• some will flow to inf tracheobronchial l.n. on R side

Thymus:
lymph vessels of thymus –> parasternal, brachiocephalic and tracheobronchial l.n

Posterior mediastinum:
Posterior mediastinal l.n. rec lymph from esophagus, post side of diaphragm and pericardium, middle/post IC spaces –> thoracic duct

Diaphragm:

• ant/post diaphragmatic l.n. on thoracic surface of diaphragm –> parasternal, post mediastinal, phrenic l.n
• diaphragmatic l.n. on abdominal surface of diaphragm –> ant diaphragmatic, phrenic, superior lumbar l.n
  
  • absorb peritoneal fluid
    

Thoracic Duct:

• in posterior mediastinum
• lies of ant side of T5-T12
• receives lymph from:
  • lower limbs,pelvis, abdomen, and left upper quadrant of body
  • and middle/upper IC spaces, post mediastinal structures
  • jugular, subclavian, bronchomediastinal lymph trunks
• originates from cisterna chyli in abdomen
• comes thru aortic hiatus
• empties eventually into L angulus venosus

Topography:
ant = esophagus
post = vertebral column
left = aorta
right = azygos v

Right Lymphatic duct:

• also in post mediastinum
• receives lymph from R upper quadrant of body: R half of head & thorax, and R upper limb
• empties into R angulus venosus

Diaphragm:

Parts of Diaphragm:
Central fibrous tendon – clover leaf shaped, no bony attachment
Peripheral musc fibers:

• sternal part – attach to post side of xyphoid process
• costal part – attach to inf six costal cartilages, and ribs – form R & L domes of diaphragm
• lumbar part – from med/lat arcuate ligaments, L1-3, form R & L crura

Med arch: made of the crura of diaphragm : musc/tendon bundles from ant surfaces of L1-L3, ant longitudinal ligament, IV discs

• R crus – L1-3/4,
• Lcrus – L1-2

Lat arch:

• Med arcuate lig – L1 body –> transv process of L1, rib 12, passes over psoas major and SNS trunk
• Lat arcuate lig – transverse process of L2 –> rib 12, passes over quadratus lumborum
  

Topography:

• central tendon attaches to pericardium via pericardiophrenic ligaments
  

Origin:

• xyphoid process (sternum)
• lower 6 costal cartilages and ant costal margin
• med/lat lumbosacral arches (lumbar arches)
• tip of 12th rib

Insertion:

• insert into central tendon of diaphragm
• b/w 12th rib and lumbar vert, diaphragm will attach to fascia over quadratus lumborum, psoas major

Function: major musc of inspiration/expiration

Actions:
1. Contraction = diaphram desc, causing inc thoracic volume, by inc vert diameter of thoracic cavity –> dec intrathoracic pressure –> Lungs EXPAND

2. Relaxation = diaphram asc, causing dec thoracic volume, by dec vert diameter of thoracic cavity –> inc intrathoracic pressure –> Lungs DEFLATE

Openings of Diaphragm:
A. Outside diaphragm
1. Sternocostal triangle – b/w rib cage & sternal and lumbar part of diaphragm – contains int thoracic a/v or sup epigastric a/v
2. Aortic hiatus – behind diaphragm, space b/w L and R crus  – contain Aorta, thoracic duct, gr. splanchnic n, azygos v (called asc lumbar v below diaphragm)

B. W/in Diaphragm
1. Caval hiatus – lies in central tendon, @ T8, to the R and post – contains IVC, R phrenic n, lymph vessels
2. Esophageal hiatus – T12 behind crossing of L & R crus – contains Esophagus, ant/post trunks of vagus

C. Structures that pierce diaphragm w/o specific opening

• SNS trunk
• Splanchnic n

Surface Projection of Diaphragm:
R = upper border of 5th rib @ midinguinal line – higher b/c of liver underneath it, attaches to liver via coronary ligament, R & L triangular ligament
L = lower border of 5th rib @ midinguinal line

Blood supply:

• Musculophrenic (int thoracic a)
• Pericardiophrenic (int thoracic a)
• Sup/inf phrenic (aorta)

Nerve supply:

• SM = phrenic n
• Central tendon SS = phrenic n
• Peripheral musc SS = IC n

Develops from:

• septum transversum
• pleuro-peritoneal folds
• mesoderm of adjacent bodywalls
• esophageal mesoderm

Ignore the developmental errors, just see where it develops from

Histology: The histology of the skin.

Embryology: Implantation. Formation and differentiation of the trophoblast. Early phases of placentation.

Implantation

• occurs w/in ant/post sup wall of uterus on day 7 after fertilization w/in functional layer of endometrium during secretory phase of menstrual cycle
• this is when the trophoblast splits into cytotrophoblast & syncytiotrophoblast
• the Uterine glands and arteries become coiled b/w opening of glands

Trophoblast

• Syncytiotrophoblast – outer multinucleated cells of trophoblast
  • no mitosis
  • invasion of endometrial stroma, eroding the endometrium a/v & glands
  • lacunae formed w/in – filled w/ nutrient material from maternal blood & glandular secretions – comes in via diffusion
  • NOTE Fetal and maternal blood never mix!!
  • Endometrial stromal cells = filled w/ glycogen + lipids =to feed to embryoblast
• Cytotrophoblast = inner mononucleated layer of trophoblast, mitotically active
  • makes cells that migrate to syncytiotrophoblast
  • from cells into mounds called primary villi (chorionic villi)

Placenta

• @ 3rd wk = Primary villi form = cytotrophoblastic core covered by syncytioblast
• mesodermal cells –> core of primary villi, grow toward decidua = secondary villi
  
• @ end of 3rd wk = mesodermal cells in the core –> differentiate into RBCs + small a/v = form villous capillary system = tertiary villi
• Tertiary villi – connect w/ a/v of mesoderm of chorionic plate and in connecting stalk
  • connect w/ intraembryonic circulation  = connect placenta w/ embryo
• Cytotrophoblastic cells in villi –> syncytioblast –> endoderm form a  thin outer cytotrophoblastic shells = attaches chorionic sac firmly to maternal endoderm
• Anchoring villi = villi from chorionic plate that extend to decidua basalis
• Free villi = villi that branch from anchoring villi, into intervillous spaces
• @ 24th day, embryo attached to trophoblastic shell by connecting stalk