Female Reproductive System 1 - VBSCI 5503 IP 3 2025 PDF

Female Reproductive System 1 VBSCI 5503 IP 3 2025 Dr. Moore Introduction A. Components 1. Ovary 2. Uterine/Fallopian tube 3. Uterus 4. Vagina/Vestibule B. Functions 1. Produces ova 2. Transports sperm 3. Site of internal fert...

Female Reproductive System 1 VBSCI 5503 IP 3 2025 Dr. Moore Introduction A. Components 1. Ovary 2. Uterine/Fallopian tube 3. Uterus 4. Vagina/Vestibule B. Functions 1. Produces ova 2. Transports sperm 3. Site of internal fertilization and gestation 3. Secretes estrogenS and progesterone (endocrine function) Developmental Anatomy A. Primordial Germ Cells (PGC) 1. Appear 1st in yolk sac endoderm (dog ~ 17 days, cattle ~ 19 days) 2. Migrates through the dorsal mesentery of the hindgut following sympathetic nerve fibers 3. Populates the indifferent gonadal ridge, before sex differentiation through gonad development  Gonadal Ridges → Yolk Sac PGCs Results Results Identical diploid (2n) cells Male: 4 haploid (1n) sperm Female: One ova and three polar bodies, all haploid (1n)  PGC (stem cells) → → most die migration Oogonia Follicle formation of meiosis 1 Primary 1 oocytes Ovulation What is the fate of most oogonia and oocytes? 2 Atresia: a natural process in which Ovum (1n) germ cells degenerate and die →zygote (2n) Structure 1. Cortex - Contains follicles and corpora lutea 2. Medulla - Contains blood vessels, lymph vessels, and nerves 3. Hilum/hilus, a ligament-like region that physically connects the ovary to the rest of the reproductive tract and serves as a conduit for nerves, blood vessels, and lymphatic vessels Cortex a. Covered by superficial epithelium, a modified mesothelium -> simple cuboidal Cortex a. Covered by superficial epithelium -> simple cuboidal b. Tunica albuginea -> dense irregular C.T. c. Remaining stroma -> loose C.T. around follicles The tunica albuginea is made up of collagen and other extracellular proteins, while the Stroma bulk of the stroma is made up of fibroblasts, reticular fibers, and ground substance. Medulla a. Blood + lymph vessels, nerves b. C.T. with smooth muscle associated with mesovarium c. Rete ovarii: a network of small tubules, male remnants Putative roles: Transporting hormones and nutrients to the developing follicles Removing waste products from the ovary Regulating ovarian blood flow Medulla a. Blood + lymph vessels, nerves b. C.T. with smooth muscle c. Rete ovarii /T. albuginea Follicle - definition - Oocyte and its encasing somatic cells at any developmental stage Follicle Do all follicles finish this development? formation Stages of follicular development a. Primordial follicle b. Primary follicle c. Secondary follicle d. Tertiary follicle = antral follicle Time to play Take a Guess! Primordial follicle, resting follicle - Single layer of squamous follicular epithelial cells covers primary oocyte Primordial follicle Cat ovary - Single layer of squamous follicular epithelial cells cover primary oocyte Primary follicle - Single layer of cuboidal or columnar follicular epithelial cells, now termed Granulosa cells Secondary follicle Stratified follicular epithelial cells/Granulosa and developing theca = steroidogenic stromal cells (androgen producing) that supports growth and maturation: * and dotted line Theca * Theca interna = Endocrine thecal cells Theca externa = loose C.T. Two layers Theca interna- vascularized endocrine thecal cells Theca externa- loose supportive C.T. Follicle lumen Granulosa Basement membrane Theca interna Theca externa Follicle Steroidogenesis Steroidogenesis Two-cell Theory Cholesterol ↓ Thecal androgen synthesis ↓ Follicular cell estrogen synthesis Zona pellucida (ZP) (1) Extracellular matrix of glycoprotein (2) Secreted by follicular epithelial cells and oocyte (3) Seen 1st in secondary follicle (4) Plays a role in fertilization control and embryo protection before implantation Zona pelucida Yes, you hatched  A-1: inspect and discuss Mesothelium and t. albuginea Follicles Primordial Secondary: ZP Tertiary: antrum, theca Corpus lutea &albicans Pregnant cat Tertiary/antral follicle = vesicular follicle a. Follicular epithelium contains antrum-fluid filled space * liquor folliculi = antral fluid first seen a scattered droplets, estradiol E2 enhanced due to binding proteins b. Well-developed thecal layers * * * liquor folliculi Preovulatory tertiary follicle = Mature follicle = Graafian follicle Stigma, site of impending rupture Increased liquor folliculi volume Bovine ovary Follicular epithelium forms: Stratum granulosum- Rests on a basement membrane Cumulus oophorus Inner portion = Corona radiata ZP Corona radiata ZP after ovulation Preovulatory mature tertiary follicles - size a. 50-70 mm - mare b. 10-20 mm - cow c. 10 mm - ewe, goat, sow d. 2 mm - bitch, queen Atretic follicles a. Degenerating b. Signs of atresia (1) Pyknosis (2) Chromatolysis (3) Glassy membrane formation Atretic follicles a. Degenerating Atretic follicles a. Degenerating b. Signs of atresia (1) Pyknosis (2) Chromatolysis (3) Glassy membrane formation Most domestic Species difference - mare species ovaries a. Cortical tissue borders ovulation fossa b. Medullary tissue located peripherally Ovarian/ovulatory fossa Interstitial endocrine cells a. Origin - theca interna cells and follicular cells from atretic follicles b. Dog, cat, rodents, but not all c. Function -> steroidogenesis Interstitial endocrine cells  B-71: inspect and discuss Developing follicles Primary oocytes Secondary follicles Granulosa Theca Corpus albuginea Muscular arteries Bovine ovary Female Reproductive System 2 VBSCI 5503 IP 3 2025 Dr. Moore Negative or positive feedback depending on time of cycle Simple Canine Estrous Cycle Developing follicles Corpus Luteum P4 E2 Ovulation LH surge -> changes follicular estradiol production into prostaglandin production Prostaglandins -> increase collagenase-> digestion of follicular wall at stigma -> ovulation Follicle ruptures and oocyte with corona radiata escapes into peritoneal cavity the infundibulum of uterine tube Corpus Hemorrhagicum: a temporary structure that forms in the ovary after ovulation. It is a collection of blood that results from the rupture of the follicle during ovulation Species Ovulatory Differences 1. Cat - copulatory stimulus, induction necessary for ovulation 2. Others - ovulate spontaneously  PGC (stem cells) → → most die migration Oogonia Follicle formation of meiosis 1 Primary 1 oocytes Ovulation 2 Ovum (1n) →zygote (2n) At Ovulation 1. 1st meiotic division completed 2. Secondary oocyte enters peritoneal cavity -> uterine tube 3. Oocyte lives ~ 1 day Fertilization A. Occurs in uterine tube B. 2nd meiotic division occurs Corpus Luteum Luteinization: Formation from remaining post- ovulatory follicular and theca interna cells Luteinization Increased cell size Increased cell number (mitosis) LH surge Steroidogenic Progesterone P4 Luteinization Increased cell size → steroidogenic capability Granulosa cells change from protein producing to steroidogenic cells Increased cell number (via mitosis) Lipid inclusions Luteinization: Yellow pigment (lutein) Corpus Albicans Time to play Take a Guess!  B-70: inspect and discuss Corpus lutea Corpus albicans Atretic follicles Pig ovary  B-69: inspect and discuss Atretic follicles ZP remnants Interstitial endocrine cells Corpora lutea Rete ovarii Mesovarium Senior dog Uterine Tube = Oviduct = Fallopian tube  Uterine Tube = Oviduct = Fallopian tube Gross Anatomy - 3 segments 1. Infundibulum - Fimbriae 2. Ampulla 3. Isthmus Microscopic Anatomy 1. Tunica mucosa - submucosa - Many folds = plicae 2. Epithelium a. Simple or pseudostratified columnar b. 2 cell types (1) Ciliated w/microvilli (2) Microvilli only -> secretory 2 cell types (1) Ciliated w/ microvilli (2) Microvilli only -> secretory Lamina propria - submucosa a. Loose c.t. -> very cellular b. Lymphocytes, plasma cells, mast cells, eosinophils Tunica muscularis a. Smooth muscle b. Predominantly inner circular Tunica serosa = Serous membrane = Visceral peritoneum a. Mesothelium b. Loose connective tissue Functions 1. Fimbriae of infundibulum - Secure ovulated secondary oocyte 4/5 2. Cilia transport oocyte to ampulla (site of fertilization) 3. Cilia (of ampulla) and muscle 1 contraction transport zygote to isthmus 3/5 4. Muscle contractions (of isthmus) propel zygote to uterus 5. Muscle contractions of uterus and uterine tube transport 2 spermatozoa to ampulla  Infundibulum Ampulla B-72: Pig uterine tube T. muscaris thickness increases from infundibulum -> isthmus Compare T. mucosa Which cells are secretory? Frequency? Isthmus  B-73 Uterine tube Cow Isthmus Make similar comparisons Ampulla Infundibulum Uterus Gross Anatomy 1. Horns (bicornuate uterus) 2. Body 3. Cervix Uterus Microscopic Anatomy 1. Tunics a. T. mucosa - submucosa = endometrium b. T. muscularis = myometrium c. T. serosa = perimetrium Endometrium = t. mucosa/ submucosa Epithelium -> simple or pseudostratified columnar Uterine glands -> simple coiled or branched tubular Lined with simple columnar epithelium Lamina propria - submucosa Loose C.T. -> very cellular- Lymphocytes, plasma cells, mast cells other WBC’s Contains melanocytes in sheep Endometrium Epithelium -> simple or pseudostratified columnar Uterine glands -> simple coiled or branched tubular Lined with simple columnar epithelium Lamina propria - submucosa Loose C.T. -> very cellular- Lymphocytes, plasma cells, mast cells other WBC’s Contains melanocytes in sheep Endometrial modifications - Caruncles of ruminants (a) = Areas of placental attachment (b) Devoid of uterine glands B-75 * * Myometrium = t. muscularis - Smooth muscle Myometrium = t. muscularis - Smooth muscle Inner: circular layer Outer portion =Stratum vasculare: Smooth muscle fibers arranged in a spiral and blood vessels Outer: longitudinal layer I Sv O Perimetrium = t. serosa a. Mesothelium b. Connective tissue B-74: Canine Ovary Uterine tube Uterine horn Epithelial Endometrial glands secretory Myometrium droplets Perimetrium B-69: Canine, compare to B-74 Cervix of the Uterus Gross anatomy Dog Cervix of the Uterus Gross anatomy a. Internal uterine ostium b. External uterine ostium c. Cervical canal Microscopic anatomy a. Tunica mucosa - submucosa (1) Highly folded Epithelium --> simple columnar (mucous cells + ciliated cells) - Secretes the "mucous plug" Lamina propria - submucosa - Dense irregular C.T. --> loose C.T. Tunica muscularis - Smooth muscle and elastic fibers (1) Inner circular layer (2) Outer longitudinal layer Tunica serosa - typical B-76: Canine Compare the cervical canal to the fornix Examine the inner uterine ostium Vagina - Vestibule 3 Tunics - Tunica Mucosa - Submucosa - Tunica Muscularis - Tunica Serosa / Adventitia Tunica Mucosa - Submucosa 1. Stratified squamous epithelium - Increases in thickness during proestrus and estrus Lamina propria - submucosa a. Loose or dense irregular connective tissue b. Lymphatic nodules common caudally Tunica Muscularis 1. Smooth muscle 2. Thick inner circular layer 3. Thin outer longitudinal layer Tunica Serosa - cranial end Tunica Adventitia - caudal end B-78: Canine vagina Inspect epithelium L. propria T. musclaris Vulva (Labia) - Skin with apocrine and sebaceous glands