Lecture 11 and 12: Functional Anatomy of the Female Reproductive Tract

Question 1

Gross Anatomy and Functions

Answer 1

1. Ovaries: production of gametes and hormones
2. oviducts: an optimal environment for fertilization
3. Uterus: sperm transport, embryo fetus development, the formation of the placenta
4. cervix: barrier for uterine protection
5. Vagina: copulatory organ
6. vulva: external genitalia, vaginal closure

Question 2

Tubular Components of the Reproductive Tract

Answer 2

Oviducts, uterus, cervix, and vagina
Four Distinct Layers
1. Serosa: outer connective tissue
- support, prevents adhesions
2. Muscularis: outer longitudinal layer and an inner circular layer
- contractions: gamete/embryo transfer, parturition
3. Submucosa: supports mucosa, varied thickness
- blood vessels, nerves, lymphatics
4. Mucosa: secretory epithelium lines lumen
- cell type present –> dependent on function

the reproductive tract develops behind the peritoneum. as it develops, the reproductive tract pushed against the peritoneum and becomes completely surrounded by the peritoneum(serosa layer), which is continuous with the broad ligament

Question 3

Broad Ligament

Answer 3

• houses vascular supply, lymphatics and nerves
• support (‘hang’) several anatomical components of the reproductive tract
• divided in 3 regions
  - mesovarium (ovaries)
  - mesosalpinx (oviducts)
  - mesometrium (uterus, cervix)

Question 4

Blood Supply of the Reproductive Tract

Answer 4

arteries:
- ovarian artery –> goes into ovarian pedicle which houses the vascular utero-ovarian plexus (UOP) –> allows for counter-current exchange of molecules
- uterine artery
- vaginal artery

Veins

• vaginal vein
• uterine vein
• ovarian-uterine vein

Question 5

Ovaries

Answer 5

profound morphological changes during reproductive cycles, which are associated with changes in physiology and behaviour

Function: production of oocytes, and hormones

• oocytes are enclosed in ovarian follicles
  
  • primordial, primary, secondary, antral (secrete estrogen and inhibin)

ovaries are composed of:

• tunica albuginea - outer connective tissue
• cortex - houses follicles and CLs
• medulla: central part (except for mares) that house vasculature, lymphatics and nerves
• hilus: formed by mesovarium: supply of vessels to medulla

Question 6

Corpus Luteum

Answer 6

develops after ovulation by differentiaion of follicle cells into luteal cells that secrete progesterone

• corpus hemorrhagicum (developing CL)
• corpus albicans (regressing CL)

theca cells differentiate into small luteal cells
granulosa cells differentiate into large luteal cells
both have LH receptors and produce progesterone

blood vessels represent ~50% of CL volume
luteal cells represent ~30%
remaining 20% = pericytes, fibrocytes, nerves, immune and smooth muscle cells

Question 7

Follicle

Answer 7

single layer of flattened cells

Question 8

Pool of primordial follicles

Answer 8

ovarian reserve

Question 9

primary follicle

Answer 9

single layer of cuboid cells

Question 10

secondary follicle

Answer 10

two-three layers of cubical cells

• zona pellucida present
• up to this stage follicle development does not depend on gonadotropins, it is controlled by local factors

Question 11

developing antral (tertiary )follcile

Answer 11

follicular fluid derives from plasma

development now depends on FSH (initially) and LH (final stages)

Question 12

antral (dominant) follicle

Answer 12

LH dependent
three layers of cells

1. theca externa
   - loose connective tissue that completely surrounds and supports the follicle
2. theca internal
   - layer just beneath the theca internal
   - LH receptors
   - produce androgens (testosterone)
3. Granulosa Cells
   - layer just beneath the theca internal (separated by a thin basement membrane)
   - no direct blood supply
   - FSH receptors
   - convert androgens into estradiol
   - produce inhibin
   - those in close proximity of the oocyte are called cumulus cells
   • intensive crosstalk with oocyte- coordinate oocyte development

Question 13

ovulating follicle:

Answer 13

induced by LH peak

Question 14

Oviducts

Answer 14

Function: transport of COC and sperm (also capacitation) provide optimal environmental for fertilization and early embryo development

divided into 3 parts

1. Infundibulum
   
   • terminal end (funnel shaped)
   • capture COC after ovulation
   • fimbriae- finger like projection s
2. Ampulla
   
   • ~50% of oviduct length
   • thick, larger diameter
   • mucosal folds, ciliated epithelium
     - fertilization
     - transport zygote
3. Isthmus
   
   • smaller in diameter
   • thicker muscular layer
   • fewer mucosal folds

Question 15

Uterus

Answer 15

bicornuate uterus = body and two horns - most common in livestock

connects oviducts to cervis

• mucosa and submucosa = endometrium
• muscularis = myometrium
• serosa= perimetrium

Nonpregnant

• secretion of prostaglandins and control of luteolysis
• transport and capacitation of sperm

Organ of Pregnancy

• provide optimal environment for the developing embryo
  
  • histotroph- embryo nutrition
• place of conceptus implantation
• maternal contribution to placenta
• expulsion of fetus and fetal placenta a parturition

Question 16

Cervix

Answer 16

canal surrounded by a thick wall with single or multiple layers of rings/folds, connective tissue, smooth muscle, secretory
mucosa (columnar epithelium ± cilia)
estrogen increases secretion of clear/ watering mucous during estrus, lubricates the vagina and flushes our foreign material

During Pregnancy

• viscous mucus (glue)
• cervical seal of pregnancy
• barrier for protection of pregnancy from foreign material

Question 17

Vagina

Answer 17

copulatory organ 
birth canal
expulsion of urine during micturition 
- poorly organised 
- highly adapted mucosal epithelium 

Cranial Portion

• derived from paramesonephrioc ducts
• columar epithelium (some ciliated)
• high degree of secretory activity

caudal portion (vestibule)

• derived from urogenital sinus
• stratified squamous epithelium
• secretion and thickness changes with stage of the cycle

Question 18

External Genitalia - vulva

Answer 18

function: provides anatomical closure to vagina and minimize entry of foreign material

anatomy: external part of reproductive tract
- labia: major and minor
- ventral commisure: clitoral fossa contains clitoris
- skin : sebaceous and sweat glands, hair follicles, adipose tissue
- constrictor vulva muscle: keep labia closed