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Question 2

Ovaries Dual Function

Answer 2

Exocrine Gland – production of gametes• Cellular production: oocytes• Duct system: oviductEndocrine Organ – production of steroids• Estrogens (e.g. estradiol)• Growth of ovarian follicles and uterine lining• Breast development; 2ndary sex charcteristics• Progestins (e.g. progesterone)• Maturation of ovarian follicles, uterine lining, breast- aka – prepare internal organs for pregnancy

Question 3

 Ovary: general structure

Answer 3

Germinal epithelium Tunica Albuginea Cortex - Contains follicles in various stages of development • Stroma (inner cortex) • CT rich in cells and relatively poor in fibers - Modified fibrocytes and scattered smooth muscle cells - Associate w/ developing follicles; become specialized as thecal layersMedulla • Loose core of fibroelastic tissue • Abundant blood vessels • Nerve and lymphatic vessels

Question 4

follicular development

Answer 4

Primordial follicle Early primary follicle Late Primary follicle Mature/Grafian follicleSecondary or antral follicle

Question 5

Primordial follicle

Answer 5

oocyte (primary), surrounded by follicular cells (simple squamous), stromal cell on outer surface

Question 6

Early primary follicle

Answer 6

oocyte grows and follicular cells become cuboidal; forming zona pellucida

Question 7

Late Primary follicle

Answer 7

oocyte and granulosa layer separated by Zona pellucida, follicular cells proliferate to form stratum granulosa, stromal cells immediately surrounding follicle form Theca folliculi

Question 8

Secondary or antral follicle

Answer 8

antrum formation begins - liquor folliculi amongst granulosa cells• Granulosa cells and oocyte form thickened mound into antrum -> cumulus oophorus• Cumulus oophorus cells surrounding oocyte = corona radiata• Theca layers differentiate, interna and externa - Interna – progesterone, highly vascularized - Externa – composed mostly of CT; aids motility -> smooth muscle cells

Question 9

Mature/Grafian follicle

Answer 9

• Dramatic growth• Antral space gets much bigger• Granulosa cells become thin lining layerBasal lamina separating granulosa from theca interna becomes prominent • Theca interna – large spindle shaped cells w/ characteristics of steroid producing cells •Theca externa: collagenous fibers and fusiform cells

Question 10

oocyte meiotic division

Answer 10

Primary oocyte – arrested for 12-15 yrs at meiotic prophase 1 -first meiotic division prior to ovulationSecondary oocyte – begins 2nd meiotic division as it leaves follicle, arrests at metaphase - Completes 2nd meiotic division upon penetration by spermatozoon

Question 11

Ovulation

Answer 11

release of oocyte into ovary (day 14 b/w follicular and luteal phases)- Oocyte and corona radiata cells separate from granulosa cells and float free in follicular fluid- stroma thins, blood flow stops in a small area (stigma)- Wall is broken down (by proteolysis) and oocyte is released and caught by oviduct  Fluid secreted by granulosa cells  turger pressure  wall rupture Theca externa smooth mm cells  contraction  aid release of oocyte

Question 12

Corpus luteum

Answer 12

collapsed follicle undergoes reorganization into corpus luteum-> secretes progesterone

Question 13

Corpus Luteum action in pregnancy

Answer 13

• Post fertilization  increases in size- Secretes progesterone to block cyclic development of more ovarian follicles- Secretes relaxin – facilitates parturition- 6 months  replaced by corpus albicans

Question 14

Corpus Luteum Action in menstruation

Answer 14

In absence of fertilization and implantation, it degenerates in 10-12 days after ovulation• Replaced by white CT scar -> corpus albicans

Question 15

Follicular Atresia

Answer 15

Degeneration of follicles (99.9%)Larger follicles: degeneration of Follical wall Smaller follicles: apoptosis of oocyte

Question 16

Follicular phase

Answer 16

FSH acts on follicles -> estrogen production • Theca cells convert cholesterol -> androgen (LH activated) • Granulosa cells convert androgen -> estrogen (FSH activated)• Estrogen has + feedback on hypothalamic -> increase FSH secretion• Eventually estrogen levels reach point where has – effect on FSH and + effect on LH

Question 17

Luteal phase:

Answer 17

LH increases and acts on corpus luteum -> Progesterone and estrogen secretion

Question 18

Fallopian tubes

Answer 18

– muscular tube situated in edge of broad ligament – 4 segmentsInfundibulumAmpulla - site of fertilizationUterineIsthmus - more muscular

Question 19

Oviducts/Fallopian tubes Function

Answer 19

-receives egg at ovulation and transports from ovary to uterus- Provides environment for fertilization

Question 20

Oviducts/Fallopian tubes wall

Answer 20

thickens from infundibulum - isthmus3 layers: Mucosa: epithelium and lamina propria (Loose CT)• Epithelium – simple columnar• Lamina propria – loose connective tissue -> longitudinal folds 2 layers of smooth mm.• Some ciliated and some not Serosa (peritoneum) – mesothelium w/ thin CT layer

Question 21

The oviducts: cyclic change

Answer 21

Follicular phase (estrogen) Increased ciliated/non-ciliated cells Increased cilia beating rateOvulation Fimbria closely opposed to ovarian surface Egg transported by cilia and peristalsis (3 day transit time)Luteal Phase (progesterone) Increased secretory/ciliated cells

Question 22

The Uterus: parts

Answer 22

Body – expanded upper portion Site of implantationCervix – constricted inferior portion  projects into vagina Endocervical canal • Os – constriction at each end of canal

Question 23

Uterus wall

Answer 23

3 layers Endometrium (mucosa)  Myometrium – muscular layer Perimetrium – uterine serosa

Question 24

Uterus endometrium

Answer 24

Endometrium (mucosa)  Simple columnar epithelium • ciliated cells and secretory cells • Uterine glands – simple tubular invaginations w/in stroma2 functionally different layers• Functional layer (stratum functionalis)  inner layer (luminal side) • Sloughed off during menstruation  resynthesized• Basal layer (stratum basale)  outer layer

Question 25

Uterus blood supply

Answer 25

• Uterine arteries – enter organ across myometrium• Arcuate arteries – • Radial branches – enter mucosa  gives off straight arteries • Straight arteries – supply basal layer• Spiral arteries – give rise to lacunae  supply functional layer • Distal portions lost during menstruation

Question 26

Myometrium

Answer 26

3 ill defined layers – inner and outer longitudinal; middle circular or oblique  Continuous w/ smooth muscle of oviducts and vagina  Tremendous growth during pregnancy

Question 27

Perimetrium

Answer 27

uterine serosa  Layer of mesothelial cells supported by a thin layer of connective tissue  Lower anterior surface  adventitia instead of mesothelium

Question 28

Endometrium and Myometrium cyclic changes each menstrual cycle

Answer 28

Menstrual phase: Day 1 – 4 -Entire functional layer sloughed offProliferative (follicular) phase: Days 4-13 (estrogen) - Epithelium restored - Stromal CT regeneration - Glands are straight with little secretory product - Blood vessels resynthesizedSecretory/Luteal phase: days 14-27 (progesterone) -endometrium growth -> due to Edema - glands enlarge and become corkscrew-shaped -> full of secretory product - Spiral arteries lengthen Ischemic phase: day 27-28 (removal of est & pro) • Glands stop secreting - Periodic contractions of smooth muscle -> ischemian -> necrosis -> necrotic functional layer removed

Question 29

Pregnancy:

Answer 29

Ovum fertilized  secretion of luteotropins by trophoblast of developing placenta to maintain corpus luteumPlacenta sustains progesterone secretion  prevents ischemic changes that would normally lead to menstruation in an infertile cycle

Question 30

Cervix

Answer 30

Mucosa - simple columnar epithelium• Changes to non-keratinized stratified squamous at portio vaginalis• Large branched mucus secreting glands (cervical glands)• Ovulation – secretory product of glands changes  less viscous Muscularis – irregular bundles of smooth muscle in fibrous CT

Question 31

Vagina

Answer 31

Mucosa stratified squamous non keratinized epithelium Lighter appearance due to glycogen storage Lamina propria – highly vascular w/ elastic tissue Numerous transverse foldsMuscularis – smooth muscle arranged in interlacing bundles Adventitia – thin inner dense CT (elastic fibers); outer loose CT

Question 32

syncytiotrophoblast

Answer 32

Outer trophoblastic layer Invades epithelium and stroma of uterine endometrium  bringing maternal blood close to placenta

Question 33

cytotrophoblast

Answer 33

Inner trophoblastic layermitotically active