Veterinary Histology: Female Reproductive System

Front 1

Ovaries: general

Back 1

- develops in the absence of testicular dtermining factors of Mullerian inhibiting factors
- houses the female gametes

Front 2

Ovaries: architecture

Back 2

- coretx and medulla
- surface is covered by a lsingle layer of low cuboidal epithelium (germinal epithelium)
- immediately benetah the germinal epithelium is the tunica albuginea
- cortex has ovarian follicles
- medulla has connective tissue and blood vessels
- horse has an inside out ovary`

Front 3

Follicle

Back 3

- basic unit of the ovary
- follicle is composed of the oocyte and its suport cells (granulosa and theca)
- oocytes are derived from yolk sac endoderm as oogonia and traverse to the gonadal ridge
- they arrest in prhophase as oocytes until ovulation

Front 4

Folliculogenesis

Back 4

- primoridal follicle--> primary follicle--> secondary follicle--> tertiary (Graafian) follicle

Front 5

Primordial follicles

Back 5

- the resting pool from which follicles are recruited into development during each cycle
- composed of the small primary oocyte surrounded by a single layer of flat stromal cells
- lcoated int the cortex next to the germinal epithelium

Front 6

Primary follicle

Back 6

- oocyte enlarges and ther eis formation of a single layer of cuboidal-shaped granulosa cells which surround the oocyte but are still separated by the basal lamina
- the oocyte becomes encased by the zona pellucida

Front 7

Zona pellucida

Back 7

- glycoprotein matrix
- separates the oocyte and the granulsa cells
- important in mediating sperm-egg interactions

Front 8

Theca cells

Back 8

- form on the outer layers of the oocyte

Front 9

Secondary follicle

Back 9

- granulosa cells become numberous and produce liquor folliculi
- antrum becomes evident
- theca cells make an internal and external layer
- granulosa cells develop receptors for FSH
- theca cells develop receptors for LH

Front 10

Liquor folliculi

Back 10

- vicous proteineous material
0 fills an antra cavity

Front 11

Tertiary/Graffian follicle

Back 11

- cells in the follicle become mature and are selected for ovulation
- oocyte sits in the cumulus oophorum and is surrounded by the corona radiata
- granulosa cell dvelop LH receptors

Front 12

Cumulus oophorus

Back 12

- a specialized neck of granulosa cells that the oocyte sits in

Front 13

Corona radiata

Back 13

- the subset of granulosa cells immediately surrounding the oocyte

Front 14

Maturation of the oocyte

Back 14

- in conjuction with the surge of LH, teh primary oocyte completes meiosis I
- at fertilization, the oocyte completes the second meiotic phase

Front 15

Corpus luteum

Back 15

- in response to teh LH surge, the tertiary follicle becomes the corpus luteum
- after teh LH surge, a corpus hemorrhagicum is formed
- granulosa and theca cells differentiate into "luteal" cells and form teh corpus luteum proper

Front 16

Corpus hemorrhagicum

Back 16

- characterized by a breakdown of the basal lamina and invasion of blood vessels and immune cells

Front 17

Corpus albicans

Back 17

- as the corpus luteum shrinks and cells are replaced by fibrous CT
- no longer produces progesterone

Front 18

Follicular atresia

Back 18

- the follicles that no not develop into teritiary follicles undergo follicular atresia
- oocytes and granulosa cells undergo apoptosis
- theca cells become interstitial cells

Front 19

Oviduct

Back 19

- muscular tube derived from Mullerian ducts
- one end is continuous with uterus and one end forms a bursa around the ovary (species dependent)

Front 20

Oviduct parts

Back 20

- opening of the oviduct is the infundibulum, which has fimbrae that catch the oocytes after ovulation
- intermediate part is the ampulla and this is where fertilization takes place
- the isthmus is next to the uterus and formst eh pars interstitialis as it transverses the uterine wall

Front 21

Oviduct: Mucosa

Back 21

- Highly folded into ridges
- clilated, simple columnar epithelium with secretory epithelial cells interspersed (peg cells)
-

Front 22

Oviduct: Muscular externa

Back 22

- smooth muscle with an inner circular layer and outer longitudinal layer
-

Front 23

Uterus

Back 23

- derived from Mullerian ducts
- has an endometrium and a myometrium

Front 24

Uterus: Mucosa

Back 24

- has 2 zones: stratum functionalis and stratum basalis
- tubular uterine glands are found in the endometrium
- caruncles

Front 25

Stratum functionalis

Back 25

- superficial layer of uterine mucosa
- degenerates after pregnancy or estrus

Front 26

Stratum basalis

Back 26

- deeper layer
- remains and will reform the stratum functionalis

Front 27

Caruncles

Back 27

- ruminants
- thickened, highly vascularized zones within the endometrium
- represent sties of attachment of maternal and placental placenta

Front 28

Myometrium

Back 28

- several layers of smooth muscle
- stratum submucosum lies beneath the mucosa and fibers run longitudinally
- stratum vasculare is the thick middle layer which contains many large blood vessels and ciruclar and oblique muscles buncles
- stratum subserosum i sthe outermost layer of smooth muscle
- under hormonal control

Front 29

Cyclical changes in the uterus

Back 29

- In response to estrogen, the endometrium is proliferative and the myometrium is contractile
- In response to progesterone, the endometrium will be its thickest and enters a secretory phase and the myometrium will be quiescent
- if pregnancy does not occur, the corpus luteum regresses, progesterone levels decline and the endometrium will undergo involution

Front 30

Cervix

Back 30

- derived rom the Mullerian ducts
- highly folded mucosa dn lined by a simple columnar epithelium
- epithelium becomes secretory under control of progesterone
- does nto have muscularis mucosa but has elastin fibers

Front 31

Vagina

Back 31

- derived from the Mullerian ducts and the urogenital sinus
- highly folded mucosa lined with stratified squamous epithelium mixed with simple columnar and goblet cells
-

Front 32

Vestibule

Back 32

- opening of the vag is lined by a folded stratified squamous epithelium admixed with goblet cells

Front 33

External gentialia

Back 33

- vulva: covered by skin with sebaceous glands and fine hair
- clitoris: made of an erectile corpora cavernosa clitoridis, a rudimentary glands clitoris and preputium

Front 34

Mammary gland

Back 34

- modified skin glands
- development is similar to sweat glands
- arrange dinto lbobules deparated by interlobar CT and fat
- lobules are arranged into distinct lobes with its own excretory duct (lactiferous duct)
- secretory units are alveoli

Front 35

Pregnancy and mammary glands

Back 35

- pregnancy induces growth of teh mammary gland with the formation fo new terminal branches of cuts and alveoli
- growth is initated by estrogen and progesterone
- reduction of intra and interlobular CT takes place
- secretion of milk proteins occurs by exocytosis and lipids are secreted by apocrine secretion

Front 36

Involution of the Mammary Gland

Back 36

- occurs after lacation
- the remaining milk is phagocytized and epithelial cells degenerate
- few alveoli remain and are lined by low cuboidal nonsecereting epithelial cells and prominant myoepithelial cells
- corpora amylacea (small concretions of protein) can be found