Female Reproductive System

Question 1

Functions

Answer 1

o Produce ova (exocrine)
o Produce female endocrine hormones responsible production of germ cells, for maintentance of accessory organs and sexual characteristics
o Nurture of infants

Question 2

Major Anatomical Components: Internal & External

Answer 2

o Internal: 2 ovaries, 2 uterine tubes (oviducts/fallopian tubes), the uterus, and vagina
o External: labia minora, labia majora, clitoris, vestibular glands
o Mammary glands - part of reproductive system since they are under endocrine control and further develop during pregnancy

Question 3

Age Related Changes in Function

Answer 3

o Menarche – first menses, initiation of pubertal development (~13 yo)
o Menstrual cycle – cyclic appearance of menses associated with fertility
o Menopause – cyclic nature of the tract becomes irregular and eventually disappears (~50 yo)

Question 4

Ovary

Answer 4

o Functions in gamete production (exocrine) and sex hormone production (endocrine)
o Almond shaped body 3cm x 1.5cm x 1cm
 Outer layer: germinal epithelium (mesothelial cells) with tunica albuginea under
• Common area of ovarian cancer
 Cortex beneath tunica albuginea with ovarian follicles in various stages of development
 Medulla - central region of ovary and consists of blood vessels and connective tissue

Question 5

Primordial Follicles

Answer 5

– present before birth, consist of primary oocyte arrested in meiotic prophase I surrounded by flattened follicular cells
 At puberty cyclic secretion of FSH stimulates groups of follicles to undergo development and produce estrogen  every 28 days up to 20 primordial follicles respond to FSH by acquiring more FSH receptors and become more columnar (become granulosa cells)
o Primary Unilaminar Follicles – primary oocyte surrounded by one layer of cuboidal cells
o Primary Multilaminar Follicles – primary oocyte surrounded by multiple layers of cuboidal cells
 zona pellucida – extracellular coat deposited by granulosa cells and oocyte
 corona radiate – tightly packed granulosa cells outside of zona pellucida

Question 6

Secondary Follicles

Answer 6

– identified by presence of antrum (cavity) formed from accumulations of hyaluronic acid-rich fluid; oocyte is arrested in meiotic prophase II
 Oocyte Meiotic Inhibitory (OMI) – within antral space is protein keeps oocyte arrested
 Theca further differentiates into theca interna and theca externa
• Theca interna – steroidogenic; produce androstenedione
• Granulosa cells - metabolize androstenedione into estrogen
• Theca externa – connective tissue

Question 7

Tertiary Follicles

Answer 7

– dominant follicle; larger than all other less developed
 Large antrum – space between granulosa cells
 Corona radiata – innermost single layer of granulosa cells surrounding the oocyte
 Cumulus oophorus – additional layers of granulosa cells not apart of corona radiata
 LH surge brings final maturation of follicle  overrides action of OMI & causes follicle to resume meiosis until arrest in metaphase II  follicle ruptures and ovulation occurs
• Remains arrested in metaphase II unless fertilization takes place

Question 8

Corpus Luteum

Answer 8

– after ovulation from remnants of ruptured graffian follicle
 Granulosa cells & theca interna that remain in ovary form temporary endocrine gland  progesterone and estrogen prevent development of any new follicles and ovulation
• Granulosa lutein cells – now secrete progesterone
• Theca lutein cells – now secrete estrogen
 No Pregnancy - granulosa lutein cells negatively feedback to pituitary reducing LH secretion and cause degeneration of corpus luteum into corpus albicans
 Pregnancy – cGH produced by placenta inhibits destruction of the corpus luteum

Question 9

Corpus Albicans

Answer 9

(remnant of corpus luteum if pregnancy does not occur) – deprivation of LH/hCG causes degeneration via autolysis and phagocytosis by macrophages

Question 10

Atretic Follicles

Answer 10

– most follicles do not fully develop into mature follicles
 Partially developed follicles become developmentally arrested and degenerate characterized by detachment of granulosa cells, death of oocyte, and formation of pycnotic (dark) apoptotic bodies
 Most prominent just after birth and during pregnancy

Question 11

Ovarian Cancer and Clinical Correlations

Answer 11

 Outer germinal epithelium of ovary forms majority of ovarian tumors
 Ova, theca, and granulosa cells are totipotent  their aberrant cell divison and differentiation leading to formation of most remaining ovarian tumors
 Reduced ovulation in women of mid-30s and older and reduced quality of oocytes reduces fertility; LH injections can induce multiple ovulations sometimes leading to multiple pregnancies

Question 12

Oviduct

Answer 12

o Infundibulum, ampulla, isthmus, pars interstitialis
o Fimbriae move during ovulation to trap and draw the ovum into the opening of the infundibulum
o Ampulla – widened region of oviduct; where fertilization takes place
o Isthmus – narrowing region
o Pars interstitialis (intramural) – opens into fundus of uterus
o Composed of 4 layers: mucosa, submucosa, muscularis, and serosa of visceral peritoneum
 Mucosal folds more prominent in the ampulla; lined by secretory (non-ciliated) and ciliated cells which are both estrogen dependent
• Ciliated cells help move ovum through the oviduct; contain 9+2 axoneme
• Secretory cells secrete proteins to nurture potential zygote
 Submucosa – connective tissue
 Muscularis - consists of inner circular and outer longitudinal layer
 Serosa - connective tissue is connected to broad ligament
o Blood products from capillaries filter into fallopian tube and combine with secretory proteins to form transudate

Question 13

Functions of Oviduct and Clinical Relevance

Answer 13

o Fimbria sweeps ovum into infundibulum of oviduct
o Peristaltic contractions of mucularis and beating motion of ciliated cells move ovum further
o Ovum is suspended in viscous oviductal fluid formed by transudation from surrounding vasculature and by estrogen stimulated secretion from secretory cells
 Progesterone stops secretory activity
o 4x more fluid accumulates in ampulla than isthmus  essential environment for fertilization
o Oviduct supports development of blastocyst for 3-4 days post ovulation
o Ectopic pregnancy – embryo develops within oviduct; requires surgical removal

Question 14

Uterus

Answer 14

o Pear shaped organ consisting of body, fundus, narrow/inferior cervix, & open uterine ostium (os)
o 3 layers: endometrium, myometrium, and perimetrium
 Endometrium (glandular) – undergoes cyclic changes referred to as menstrual cycle
• Epithelium and lamina propria containing simple tubular glands
• Simple columnar lining with ciliated and secretory cells
• Glands fold tightly during post-ovulatory secretory (luteal) phase of menstrual cycle to increase surface area for secretion
• Glands straighten during proliferative phase
• Functionalis layer - lost during menstruation; supplied by coiled arteries
• Basalis layer - maintained during menstruation; supplied by straight arteries
o Glandular cells provide new epithelial cells of uterus after menstruation
 Myometrium – thickest component of uterus composed of smooth muscle cells interspersed by connective tissue; arcuate arteries that go to endometrium
• During pregnancy, smooth muscle hypertrophies and hyperplasia (increase #)
• Enzymatic destruction of some of muscle cells following birth
 Perimetrium – continuous with broad ligament
• Outer adventitia composed of connective tissue
• Serosa of connective tissue and mesothelial cells that form part of broad ligament

Question 15

Clinical Relevance of Uterus

Answer 15

o Dating of endometrium can be used to assess the function of ovary and indirectly the hypothalamus and pituitary in cases of infertility
 Infertility can be caused by shortened luteal phase diagnosed from endometrium
o Endometriosis – originates from endometrial tissue is also common

Question 16

Cervix

Answer 16

– gatekeeper to uterus
o Endocervical canal (tip) – simple columnar epithelium that is highly folded into crypts
 At ovulation epithelium secretes aqueous fluid that allows sperm to penetrate cervix
 During menstrual cycle (luteal phase) secretes viscous fluid that prevents penetration of sperm or microorganism through the cervix
o Outside cervix projecting into vagina lined by stratified squamous non-keratinized epithelium
o Cervical cancers most frequently arise in region of transition from endocervical simple columnar epithelium to outside cervix stratified squamous non-keratinized epithelium
 Diagnosed via Papanicolou stain test
 Cervical cancer often caused by HPV virus

Question 17

Vagina

Answer 17

o Consists of 3 layers: mucosa, muscular layer, and adventitia
o Epithelium lining mucosa is non-keratinized stratified squamous epithelium like outer cervix
 After menopause, thinning of this layer & increased infections
o Smooth muscular layer composed of longitudinal (rugae) bundles
o Adventitia - unites vagina with surrounding tissue

Question 18

External Genitalia

Answer 18

o Vestibular glands – (glands of Bartholin and Skene’s glands) situated on each side of vestibulum
o Labia minora – folds of skin with core of spongy tissue; covered with keratinized squamous epithelium and lacking sebaceous glands and adipose tissue
o Labia majora – folds of skin that contain adipose tissue and smooth muscle; external surface covered by stratified squamous keratinized epithelium and hair
 Numerous sebaceous, sweat glands, and hair follicles
o Clitoris – contains venous spaces of erectile tissue, divides in midline and surrounded by connective capsule
 Covered with stratified squamous keratinized epithelium
 Pacinian corpuscles – sensory structures that contribute to arousal and sexual satisfaction
o Urethra is lined by pseudostratified columnar epithelium

Question 19

Mammary Gland

Answer 19

– simple columnar epithelium
o Non-Pregnant Gland – during puberty, lactiferous ducts elongate and branch with lobule developing at end of each INTERlobar duct
o Pregnant Lactating Gland
 Secretory alveoli form around INTRAlobar ducts
 Milk produced by epithelial cells of alveoli that accumulates in lumen & lactiferous ducts

Question 20

Mammary Gland Clinical correlation

Answer 20

o Breast cancer – second deadliest cancer (15%) in women behind lung cancer;
 Arises from epithelial cells of intralobular ducts (2/3) or acini (1/3)
o Fibrocystic breast disease-benign disease with nodules arising from stromal component

Question 21

Menses and Proliferative (folicular) phase

Answer 21

o	Menses (4 days) – characterized by hemorrhage and shedding of endometrium
o	Proliferative (follicular) phase (9 days)
	Gradual increase in estrogen stimulates proliferation of endometrial basalis
	Elongation of straight tubular glands (narrow lumen), increase in stromal cells, and growth of coiled arteries into the stroma controlled by estrogen; endometrial doubles/triples in thickness

Question 22

Secretory (Progestational/progravid) Phase (13 days)

Answer 22

– under influence of corpus luteum
 Estrogen from theca lutein cells and progesterone from granulosa lutein cells cause endometrium to thicken further in preparation for implantation
 Tubular glands and arteries become coiled and convoluted
• Secretions nourish the ovum moving down through the uterus
• Secretory products dilate the lumens of coiled glands and edema of stroma results in maximum thickness of endometrium

Question 23

ischemic (Menstrual) Phase

Answer 23

– if no implantation, corpus luteum begins to regress resulting in marked decline of ovarian hormones; functionalis undergoes sporadic episodes of cessation of its blood supply by constriction then dilation of coiled arteries leading to intermittent hypoxia, ischemic necrosis, and exfoliation of the functionalis leading to menstruation

Question 24

Early Follicular Phase

Answer 24

– under influence of FSH
 Up to 20 pareantral follicles develop with each new cycle
 Day 6-8 dominant follicle begins to secrete estrogen
 Hypothalamus releases gonadotropin releasing hormone that regulates FSH and LH
 FSH causes flattened follicular cells of primordial follicle to become granulosa cells and secrete estrogen; estrogen levels rise as number of granulosa cells increase
 Gradual rise in estrogen stimulates the proliferative phase and negative feedbacks to FSH

Question 25

Mid-Follicular Phase

Answer 25

– growing follicle and dominant follicle secretes larger amount of estrogen  Plasma levels of estrogen >150pg/ml for more than 36 hours interrupts negative feedback loop and positive feedback takes effect inducing pre-ovulatory LH and FSH surges  LH causes increased follicular secretion of progesterone which stimulates collagenolytic enzymes that weaken the wall of dominant follicle leading to rupture and release of ovum

Question 26

Luteal Phase

Answer 26

– gradual increase in estrogen produced by theca lutein cells of corpus luteum and progesterone produced by granulosa lutein cells of corpus luteum develop the secretory phase  High progesterone levels inhibit the positive feedback action of estrogen and inhibits follicular development  NO implantation 12 days after ovulation - corpus luteum degenerates and stops production of progesterone and estrogen • Inhibitory action of estrogen & progesterone removed allowing LH/FSH increase o New follicles begin to grow and menses occurs  Implantation occurs - stromal cells of endometrium enlarge in response to increased progesterone and corpus luteum is rescuted by hCG from placenta that replaces LH

Question 27

Birth Control MEchanism and IVF

Answer 27

o Injecting gonadotrophin facilitates multiple ovulations thus multiple oocytes o Birth control pills contain progestins that inhibit follicular development and ovulation; mimic secretory phase when steroid levels are elevated and body thinks its pregnant