Female Reproductive System Flashcards
Functions
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
Major Anatomical Components: Internal & External
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
Age Related Changes in Function
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)
Ovary
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
Primordial Follicles
– 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
Secondary Follicles
– 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
Tertiary Follicles
– 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
Corpus Luteum
– 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
Corpus Albicans
(remnant of corpus luteum if pregnancy does not occur) – deprivation of LH/hCG causes degeneration via autolysis and phagocytosis by macrophages
Atretic Follicles
– 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
Ovarian Cancer and Clinical Correlations
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
Oviduct
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
Functions of Oviduct and Clinical Relevance
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
Uterus
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
Clinical Relevance of Uterus
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
Cervix
– 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
Vagina
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
External Genitalia
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
Mammary Gland
– 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
Mammary Gland Clinical correlation
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
Menses and Proliferative (folicular) phase
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
Secretory (Progestational/progravid) Phase (13 days)
– 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
ischemic (Menstrual) Phase
– 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
Early Follicular Phase
– 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