Female reproductive anatomy

Question 1

Outline the embryonic derivations of the female reproductive tract

Answer 1

Vestibule, vulva, clitoris and urethra: develop from the urogenital sinus
Uterine tube and urethra: develop from the paramesonephric ducts
The vagina: formed from the fusion of the paramesonephric ducts at the level of the urogenital sinus. the level of fusion that occurs between the ducts determines the type of uterus formed.

Question 2

Describe the gross anatomy of the female reproductive tract

Answer 2

internal genital organs: uterine tube, uterus, vagina, vestibule
external genital gonads: vulva, clitoris, urethra

Question 3

Describe the development of the broad ligament

Answer 3

• the reproductive tract develops in a retroperitoneal position
• the uterine horns and rectum push into the abdominal cavity and become surrounded by peritoneum, suspends the tract in the cavity, forms a double layer of connective tissue over the ovaries, oviduct, uterus, cervix and vagina: the broad ligament.

Question 4

Describe the supporting ligaments of the reproductive tract

Answer 4

Broad ligament: supports and suspends ovaries, oviduct, uterus, cervix and vagina, houses the vascular supply, lymphatics and innervation
Round ligament: runs from the uterine horn to the inguinal canal, homologous to the gubernaculum
Suspensory ligament: runs from the cranial ovary to the body wall
Proper ligament: connects the ovary to the uterus

Question 5

Describe the components of the broad ligament

Answer 5

The mesovarium: houses the blood and lymphatics supplying the ovary
The mesosalpinx: supports the oviducts, acts as a bursa surrounding the ovary, amount of coverage depends on the species (complete sac in the bitch, small in mares)
Mesometrium: supports the uterine horns and the body of the uterus

Question 6

Describe the blood supply of the ovaries

Answer 6

Ovarian artery: direct from the aorta, supplies the ovary
branches (the uterine branch) and supplies the tip of the uterine horn, anastomoses with the uterine artery in the broad ligament

Question 7

Describe the utero-ovarian countercurrent system

Answer 7

the ovarian vein is intertwined with the ovarian artery in some species (especially the cow, NOT the mare), enables PGF2A from the uterus in the ovarian vein to be transfered into the ovarian artery: PGF2A is needed to lyse the CL, system enables it to remain in high concentration needed to lyse the CL
PGF2A secreted by endometrium –> enters ovarian vein –> diffuses into ovarian artery –> delivered back to the ovary

Question 8

Describe why mares do not require a utero-ovarian countercurrent system

Answer 8

In the mare, PGF2A is not metabolised as quickly and so it can be recycled. It is also able to induce lysis of the CL at lower concentrations and so a countercurrent system isn’t needed- no need to concentrate levels of PGF2A within the ovarian artery

Question 9

Describe the vascular supply of the uterus

Answer 9

The uterine arteries branch from the internal iliac artery,
run within the broad ligament, can be palpated at the shaft of the ilium
NOT present in carnivores
the ovarian vein is larger than the uterine vein and is responsible for the majority of drainage from the ovaries and uterus

Question 10

Describe the vascular supply of the vagina

Answer 10

The vaginal artery

Question 11

Describe the innervation of the female reproductive tract

Answer 11

Innervation:
The ANS
Ovaries: SNS from the mesenteric plexus
Uterus, cervix, vagina: PSNS and SNS from pelvic plexus

Question 12

Recognise key anatomical features of the bovine ovary (all species except mare)

Answer 12

• germinal epithelium covering the cortex
• central medulla, contains lymphatics and blood vessels
• follicles are located primarily on the outer surface of the ovary
• after ovulation the corpus luteum develops, regresses to the corpus albicans

Question 13

Recognise key anatomical features of the equine ovary

Answer 13

• follicles develop at the centre of the ovary, not at the surface, ovulation occurs in one place: the ovulation fossa
• large ovaary, 2cm when inactive, 10cm when active
• often difficult to palpate structures rectally: can’t feel CL or follicle
• the vascularised medulla forms the outer layer of the ovary

Question 14

Describe the structure of the oviduct

Answer 14

-The oviduct has 3 regions: infundibulum, ampulla, isthmus
-Fimbriae: finer-like folds of the infundibulum, increase its SA, maximise chances of catching oocyte
- when caught, oocyte passes through the ostium of the infundibulum into the ampulla
- Ampulla: large lumen, secretory functions, oocyte passes through smaller lumen into isthmus (checkpoint site in the mare- unfertilised eggs can’t pass this point)
Isthmus: connects to the uterus.

Question 15

Describe the functions of the oviduct

Answer 15

• sperm transport and storage via smooth muscle contraction
• ampulla: site of fertilisation
• oocyte transport
• provides correct environment for fertlisation
• gamete transport
• oviduct secretions: provide correct environment for fertilisation

Question 16

Describe the functions of the uterus

Answer 16

• prostaglandin production to control cyclical activity (not in the bitch)
• sperm transport and storage
• contributes to the placenta
• provides environment for develop
• contracts to assist with parturition

Question 17

Describe the structure of the uterus

Answer 17

• serosa
• myometrium
• endometrium (submucosa and mucosa)
  Morphology: varies according to species
  general: uterine body, horns, in some species there is an intercornual ligament (useful for locating horns in the cow)

Question 18

Describe the different types of uterus

Answer 18

Duplex: 2 cervical canal, separate uterine horns, common in marsupals
found in rabbits: offspring can have different dads
Bicornuate: 2 uterine horns, small uterine body
Mare- short horns, large body
bitch/sow/queen: long horns
Simplex: single uterine body, small remnants of horns remain
humans

Question 19

Describe the structure of the uterine tissue

Answer 19

• thin and transparent outer layer- perimetrium
• myometrium: muscle layers (circular and longitudinal). the myometrium has increased tone when oestrogen levels are high: assists sperm transport
  Endometrium: SM and M, high oestrogen cause the development of uterine glands here, these secrete materials to assist with maintenance of early pregnancy. progesterone triggers maximum secretion levels.

Question 20

Describe species different with regards to the uterine tissue

Answer 20

Decidua: endometrium forms this in primates, layer is shed if implantation doesn’t occur (menstruation)
Sow and mare: many endometrial folds, contributes to placenta
cow and ewe: caruncles protrude from endometrial surface, act as attachment sites for placenta, highly vascularised

Question 21

Describe the functions of the cervix

Answer 21

• acts as a barrier to the uterus during pregnancy and other stages
• opens during oestrus and produces mucous, acts as lubricant to protect cervix, vagina and vestibule, flushes out excess sperm and foreign bodies
  barrier to sperm transport: cow, ewe, human
  allows sperm transport: mare, sow, bitch

Question 22

Describe the anatomy of the cervix

Answer 22

• number of folds differs according to species

generally a lumen surrounded with single (bitch, queen) or multiple rings (cow, ewe, sow, mare)

Question 23

Describe species differences in the anatomy of the cervix

Answer 23

Cervical rings: 
single- bitch, queen
multiple- mares, ewes, cows, sows
varibale degree of patency:
- interlocking folds: cow, ewe
-  spiral interlocking folds: sow
- loose folds: mare

Question 24

Describe the anatomy of the vagina

Answer 24

simple tube structure, has histological subdivisions:
- Cranial vagina: secretory epithelum, from vaginal plate
caudal vagina: stratified squamous epithelium

Question 25

describe the anatomy of the vestibule

Answer 25

Found between the urethral orifice and the vulva, has joint uro-genital functions
stratified sqaumous epithelium
There is a urethral diverticulum in cows and ewes

Question 26

Describe the functions of the vagina

Answer 26

copulation
parturition
micturition

Question 27

Describe the hormonal effects on the caudal vagina

Answer 27

• the secretory activity and thickness varies with endocrine status
• the epithelium thickens when E2 is high, provides mechanical protection and blocks microbes entering the submucosa

Question 28

Describe the anatomy of the vulva

Answer 28

• Labia: 2 labia, major and minor, meet to form 2 commissures (dorsal and ventral)
• The clitoris is houses under a transverse frenulum (the clitoral hood)
• The clitoral fossa surrounds the clitoris
  Clitoral sinus present in some species: pathogens,