Female reproductive anatomy Flashcards
Outline the embryonic derivations of the female reproductive tract
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.
Describe the gross anatomy of the female reproductive tract
internal genital organs: uterine tube, uterus, vagina, vestibule
external genital gonads: vulva, clitoris, urethra
Describe the development of the broad ligament
- 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.
Describe the supporting ligaments of the reproductive tract
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
Describe the components of the broad ligament
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
Describe the blood supply of the ovaries
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
Describe the utero-ovarian countercurrent system
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
Describe why mares do not require a utero-ovarian countercurrent system
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
Describe the vascular supply of the uterus
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
Describe the vascular supply of the vagina
The vaginal artery
Describe the innervation of the female reproductive tract
Innervation:
The ANS
Ovaries: SNS from the mesenteric plexus
Uterus, cervix, vagina: PSNS and SNS from pelvic plexus
Recognise key anatomical features of the bovine ovary (all species except mare)
- 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
Recognise key anatomical features of the equine ovary
- 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
Describe the structure of the oviduct
-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.
Describe the functions of the oviduct
- 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
Describe the functions of the uterus
- 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
Describe the structure of the uterus
- 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)
Describe the different types of uterus
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
Describe the structure of the uterine tissue
- 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.
Describe species different with regards to the uterine tissue
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
Describe the functions of the cervix
- 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
Describe the anatomy of the cervix
- number of folds differs according to species
generally a lumen surrounded with single (bitch, queen) or multiple rings (cow, ewe, sow, mare)
Describe species differences in the anatomy of the cervix
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
Describe the anatomy of the vagina
simple tube structure, has histological subdivisions:
- Cranial vagina: secretory epithelum, from vaginal plate
caudal vagina: stratified squamous epithelium
