female reproductive system

topography es importante

» Solid, ellipsoid organ

• Follicles (each containing a single ovum)

• Projection of follicles can make it irregular-shaped

• More follicles (e.g. polytocous species) = more lumpy

» In cross-section:

• Loose vascular zone/medulla in centre

• Outer dense parenchymatous zone

» Horses slightly different

• More kidney shaped

• Reversed structure (vascular zone outside, parenchymatous zone + follicles inside) F - and single location where they ovulate from - ovulation fossa

follicle production

» Follicles develop and progress through several stages:

1) Primordial follicle (smallest)

Single layer of flat granulosa cells

2) Primary follicle

Flat granulosa cells thicken→ cuboidal cells

3) Secondary follicle

Several layers of cells with fluid-filled spaces

4) Tertiary (Graafian) follicle

Mature, fluid spaces joint up

» Only a small number of follicles mature all the way

• There is atresia and regression at every stage

» Follicles develop and progress through several stages:

6) Graafian follicle ruptures (ovulation)

Fluid flushes ovum to uterine tube

7) The remaining follicle tissue bleeds a little

8) Proliferation of tissue to form corpus luteum

If pregnant, CL (corpus luteum-produces progesterone) persists

9) If not pregnant CL regresses

A connective tissue scar forms; the corpus albicans (white body)

» Ovulation and maintenance or regression of CL involve a complex interplay of hormones e.g.

• FSH and LH - ovulation

• Progesterone - persistent corpus luteum

• PGF2α - regression of corpus luteum

uterine tube

» AKA oviducts, salpinx/uterine tube. Not Fallopian!

» Function: capture and transport ova to the uterus; usually site of fertilisation

» Lined internally by ciliated epithelium

» Expanded near ovary into the infundibulum

• Funnel shaped

• Fimbriae on free edge

» Ampulla (‘flask’) makes up middle portion

» Isthmus is the narrower (sometimes convoluted) portion

» Junction with uterine horn can be gradual or abrupt

uterus

» Appearance varies considerably between species

• Develops from paramesonephric ducts that fuse

» Size, position and anatomy changes with age and physiological activity!

» Comprised of horns, body and cervix

» Cervix limits access from vagina

• Forms sphincter

• Thick mucosal folds interdigitate, can occlude cervical canal

• Cervical mucosa secrete mucus, forming a plug

uterine tube NOT the same as uterine horn

uterus zoomed in - tubular

» Uterine wall is three-layered

» Mucosal layer (endometrium) internal lining

• Thickness varies with oestrus cycle

• Numerous tubular glands

• Ruminants have uterine caruncles (attachment sites of embryonic membranes), attach to foetal cotyledons

» Muscle layer (myometrium)

• External longitudinal muscle layer

• Internal circular muscle layer

• Smooth (involuntary) muscle

• Responsible for uterine contractions

• Coordinated activity: longitudinal contractions ‘shorten utuerus’ while circular contractions push out contents.

outer layer of uterus

Serosal layer (perimetrium) outer surface

• Continuous with the broad ligament (like a mesentery in gi tract)

vagina, vestibule and vulva

» Vagina and vestibule together form the rest of the internal tract

» Vagina cranially, from cervix to urethra

• Purely reproductive passage

• Mostly retroperitoneal

» Vestibule caudally, from urethra to external vulva

• Combined reproductive and urinary functions

• Caudal to ischial arch, variable slope ventrally to vulva

• Urethral opening ventrally

vagina, vestibule and vulva opened up

» Urethral opening – features nearby can complicate bladder catheterisation

• E.g. suburethral diverticulum in pig and cow

• E.g. flanked by two grooves in dog

» Vestibular glands

• Varies - small and numerous openings in dogs, large bilateral (on both sides) glandular mass each drained by single duct in cows

• Lubricate vestibule during copulation and parturition (birth)

comparing vagigies

» Vulva is the external genital opening and tissues

• Labia either side

• Labia meet at dorsal and ventral commissures

• Clitoris, the female homologue of the penis (or vice versa!), lies within ventral commissure, contained within the clitoral fossa

ligaments

» Broad ligament = folds of peritoneum, suspending tract from dorsal body wall

• Ovary (mesovarium)

• Uterine tube (mesosalpinx)

• Uterine horns and uterus (mesometrium)

• Cervix

» Broad ligament also encloses blood vessels, nerves and some other ligaments

• Suspensory ligament of the ovary (last rib to ovary)

• Ovarian/proper ligament (ovary to uterine horn)

• Round ligament of uterus (uterus to inguinal canal)

» Intercornual ligament (connects uterine horns)

• Well developed in ruminants

broad ligament

Mesometrium

Mesovarium (and suspensory ligament of ovary)

Mesosalpinx

ovarian bursa = pouch of mesovarium and meosalpinx

Round ligament

Proper ligament

ovarian bursa

» Folding of mesovarium and mesosalpinx creates a “pouch”

» Communicates with peritoneal space

» Pouch opening width varies

• Species difference

» Can contain fat

blood supply to reproductive tract

1. Ovarian artery

• Direct branch of aorta

• Variably convoluted

2. Internal pudendal arteries

• Supply external genitals

• Branch off to form:

3. Vaginal artery

• Supplies vagina and rectum

4. Uterine artery

• Branch of the vaginal artery

• Anastomoses w/ ovarian and vaginal arteries

» The veins broadly accompany the arteries