Ch.2: Female Reproductive tract

rectogenital pouch

separates the rectum and reproductive tract

4 layers of the female reproductive tract

• serosa (outermost)

• muscularis 

• submucosa

• mucosa (innermost)

Serosa layer

outermost layer of the female reproductive tract. a single layer of squamous epithelial cells

muscularis layer

deep to the serosa layer of the reproductive tract. consists of an outer longitudinal layer and an inner circular layer of smooth muscle

submucosa layer

deep to the muscularis layer. houses the blood vessels, nerves, and lymphatics to suppert the muscosal layer

mucosa layer

the inner most layer of the reproductive tract. contains secretory epithelium.

each part of the reproductive tract has different types of mucosal epitheliam (i.e. cilliated, non-ciliated, squamous, cuboidal)

types of mucosal epithelium lining the oviducts

ciliated and non-cilitaed simple columnar epithelium

mucosal epithelium of the posterior vagina

stratified squamous epitheliumm

broad ligament

a double layered connective tissue sheet that supports and suspends the ovaries, oviduct, uterus, cervix, and cranial vagina. Houses the blood supply, lymphatics, and nerves to the reproductive tract

the BL is continuous with the peritoneum of the abdomen

3 components of the broad ligament

• mesovarium

• mesosalpinx

• mesometrium

mesovarium

the portion of the broad ligament that covers the ovaries and forms the hilus

mesosalpinx

the portion of the broad ligament that covers the oviducts and serves as a bursa-like (fluid-filled) pouch that surrounds the ovaries.

helps to orient the infundibulum so that the ova released can be directed into the oviduct

mesometrium

the portion of the broad ligament that covers the uterine horns and the body of the uterus. 

the dorsal portion of this is continuous with the dorsal peritoneum and the uterus “hangs” from the dorsal body wall

utero-ovarian ligament

aka the proper ligament of the ovary. an additional supportive ligament for the ovary that attaches it to the uterus.

Not a part of the broad ligament

2 main functions of the ovary

cytogenesis (produce the ova) and production of the hormones estrogen and progesterone

layers of the ovary

• germinal epithelium (outermost)

• tunica albuginea

• ovarian cortex

• ovarian medulla (innermost)

germinal epithelium layer of the ovary

consists of cuboidal epithelial cells

tunica albuginea

an outerlayer of connective tissue surrounding the ovary

ovarian cortex

deep to the tunica albuginea. houses the oocyte population, corpus luteum, and corpus albicans

ovarian medulla

deep to the ovarian cortex. central part of the ovary that houses the vasculature, nerves and lymphatics.

composed of relatively dense connective tissue.

corpus albicans 

degenerating corpus lutem

can be identified by its white, scar-like appearance due to its increasing ratio of connective tissue (white) to secretory tissue

primary ovarian structures found in ovarian cortex

• primordial follicle

• primary follicle

• secondary follicle

• antral (tertiary) follicle

• copora lutea

• corpora albicantia

folliculogenesis

the process where by immature follicles develop into more mature follicles and become candidates for ovulation 

primordial follciles

microscopic. the most immature and smallest encountered follicle in the cortex. oocyte in this follicle is surrounded by a single layer of squamous epithelium

primary follicle

microscopic. slightly more developed than the primordial follicle. oocyte is now surrounded by a single layer of cuboidal epithelium (aka follicular cells)

secondary follicle

microscopic. characterized as 2 or more layers of follicular cells (cuboidal epithelium), but lacks an antrum (cavity)

zona pellucida

a relatively thick translucent layer that surrounds the oocyte in the secondary follicle

antral follicle

characterized by having a fluid-filled cavity called the antrum

follicular fluid

the fluid within the antrum of the antral follicle

graafian follicle

the antral follicle that has become the dominant pre-ovulatory follicle 

3 layers of an antral follicle

• theca externa

• theca interna

• granulosal cell layer

theca externa

outermost cellular layer of the antral follicle.

composed of loose connective tissue that completely surrounds and supports the follicle

theca interna

deep to the theca externa. produces androgens (i.e. testosterone) under the influence of LH

granulosal cells

aka membrana granulosa. separated from the theca interna through a basement membrane

produces estrogen, inhibin, and follicular fluid.

Has FSH receptors

governs oocyte maturation

corpus hemorrhagicum

structure created when ovulation occurs. A combinaton of ruptured blood vessels and a small protrusion of granulosal and thecal cells through the apex of the follicle that was created when the follicle collapsed.

what happens to the thecal interna and granulosal cells after the formation of the corpus hemorrhagicum

they differentiate into luteal cells to form the corpus luteum

corpus luteum

produces progesterone that is essential for the maintenence of pregnancy

3 components of the oviducts

• infundibulum

• ampulla

• isthmus

infundibulum

ovarian end of the oviduct that consists of a funnel-shaped opening that “captures” the ovulated oocyte and directs it into the ampulla of the oviduct

ampulla

after the infundibulum. a thick portion of the oviduct, occupying 1/2+ the length of the oviduct.

contains portions characterized by many fern-like mucosal folds with ciliated epithelium

isthmus

smaller in diameter than the ampulla. consists of a thicker muscular wall and less mucosal folds

ampullary-isthmic junction

an ill-defined junction between the oviduct’s ampulla and isthmus

uterotubal junction

the point of junction between the uterus and oviduct’s isthmus

function of the oviduct muscularis layer

to transport the ova and sperm to the site of fertilization (ampulla) 

function of the oviduct mucosal layer

secrete a fluid that optimizes fertilization capabilities of the sperm and maintain an optimal environment for the free-floating ova and an environment to facilitate the developing embryo

3 anatomical types of uteri

• duplex

• bicornuate

• simplex

duplex uterus

characterized as having 2 cervical canals that separate each uterine horn into distinct compartments

• either a duplex that has a single vaginal canal opening to the exterior and biforcates in the interior into two vaginas and two cervices

• or a duplex that has 2 uterine horns and 2 distinct cervical canals connected to a single vaginal canal

bicornuate uterus

characterized by having 2 uterine horns and a small uterine body

simplex uterus

characterized by having a single uterine body with small rudiments of a structure resembling a uterine horn (potentially)

unique names of the components of the uterus

serosa = perimetrium

muscularis = myometrium

mucosa + submucosa = endometrium

perimetrium

serosal layer of the uterus.

is a part of the peritoneum and continuous with the mesosalpinx

myometrium

longitudinal and circular layers of the muscularis.

provides motility (contraction) for the uterus, and gives uterus a uterine tone to transport sperm and mucus-like material produced by uterus

functions of the uterus

sperm transport, luteolysis and control of cyclicity, environment for preattachment embryo, maternal contribution to the placenta, and expulsion of the fetus and fetal placenta

endometrium

mucosal and submucosal layers of the uterus.

mucosal: secretes materials into lumen of uterus that enhances embryo development and sperm viability. houses uterine glands, which reach full secretory function under estrogen influence

prostaglandin F2𝛂

produced by the uterine endometrium cells that cause luteolysis or regression of the corpus luteum if animal is not pregnant.

caruncles of the endometrium

small, non-glandular protuberances that are highly vascularized and will give rise to the maternal portion of the placenta

similar to endometrial folds in other species

cervix

a relatively thick-walled non-compliant organ that serves as a barrier to sperm transport (not in mare or sow), isolates the uterus from the external environment during pregnancy, and forms a highly viscous mucus barrier during pregnancy

cervical canal

lumen that is surrounded by a single or multiple folds or rings protruding into it

cervical seal of pregnancy

the barrier that is created under the influence of progesterone. a highly viscous mucus produced by the cervix that “glues” the folds of the cervix together during pregnancy

function of the vagina

acts as the copulatory organ, as well as the site for expulsion of urine during urination

mucosal epithelium of the cranial vagina

columnar and highly secretory in nature

fornix vagina

a crypt or pocket that the cervix creates when it protrudes into the cranial vagina

composed of columnar epithelial cells that secrete copious quantities of mucus during estrus (like the cervix)

caudal vagina or vestibule 

stratified squamous epithelium

during estrus (high [estrogen]), the epithelium and mucosa thickens drasticallyto protect the vagina during copulation and prevent microorganisms from gaining entrance into the vasculature in the submucosa

belongs to the urinary and genital system

gartner’s ducts and wolffian duct

found in the vestibule, have no apparent function but are embryonic remnants of the male reproductive system of the embryo

vulva

the external part of the female reproductive tract consisting of two labia (major and minor) that meet in the medial portion of the tract to form two sites of union (commissures)

labia

form a closure that minimizes the entrance of foreign material into the vagina

constrictor vulvae muscles

small bundles of smooth muscle imbedded in the adipose tissue of the labia that ensure the labia stay in a close apposition

perineum

the region that surrounds the anus and the vulva and covers the pelvic outlet

clitoral fossa

housed in the ventral commissure of the vestibule that contains the clitoris

clitoris

composed of erectile tissue and is covered with stratified squamous epithelium

vestibular glands

housed in the submucosa of the caudal portion of the vestibule that actively secrete a mucus-like material during estrus