LEC37: Microstructure of the Female Reproductive Tract Flashcards
functions of female reproductive system
1) produce ova thru oogenesis
2) facilitate, transport germ cells & spermatozoa to increase chances of fertilization
3) maintain implanted embryos through gestation
4) nurture infants postnatally thru lactation
what controls female reproductive system functions
hormal and nervous system mechanisms
components of female reproductive system
1) ovaries
2) uterine tubes (oviducts)
3) uterus (myometrium, endometrium, cervix)
4) vagina
5) external genitalia
6) mammary glands
7) placenta
what attaches ovary-uterus
ovarian ligament, mesovarium attaches ovary to broad ligaments of uterus
where does fertilization occur
by ampulla-isthmus border of fallopian tube
another name for body of uterus
corpus
what collects released oocyte
fimbriae of uterine tube
what is at the lower end of the birth canal
vagina
what is ovary covered with
simple cuboidal epithelium that’s continuous w/ mesothelial lining of peritoneal cavity
where are germ cells released
directly into peritoneal cavity
what does oviduct connect to
attached to broad ligaments of uterus
how does oocyte > uterus
peristaltic contractions of muscle coat surrounding oviducts
where is uterus
medially in pelvic cavity
uterus-vagina connection is what
uterine ostium
which part of vagina opens into uterus
upper end of vagina
what is vagina latin for
sheath
vagina walls made of
muscle
what is lower end of birth canal
vagina
cell type in folds of vagina
stratified squamous epithelium
when does oogenesis begin
during prenatal life
what happens during fetal life re: oogonia?
oogonia > 1o oocyte, meiosis I begins, suspends in prophase
when do 1o oocytes complete meiosis I and what are products
1o oocyte suspended until ovulation as a 2o oocyte after puberty; occurs on an individual basis; produces 2o oocyte and 1st polar body
how long might a 1o oocyte remain suspended in prophase
45-50 years
a reason for trisomy 21 with increased maternal age
when does 2o oocyte complete 2nd meiotic division
after fertilization; 2o oocyte splits into ovum & 2nd polar body
ovarian ligament
connects ovary-lateral surface of uterus
cortex of ovary
area with follicles, corpus luteum, and stroma
medulla of ovary contains
blood vessels
how many 1o oocytes at birth?
2 million
how many 1o oocytes at puberty?
400,000
what stimulates 2o follicle production
cyclic FSH secretion by anterior pituitary
what supports full reproductive function?
estrogen produced from developing follicles
how many primoridial follicles stimulated to develop each month?
20-50
what was thought to give rise to germ cells & where do they actually arise from?
germinal epithelium, now know it’s yolk sac
what is tunica albuginea
connective tissue covering of the ovaries
parallel to germinal epithelium lining the ovary
follicular development stages
1) primordial follicle
2) early primary follicle
3) late primary follicle
4) secondary follicle
5) mature graafian follicle
primordial follicle characteristics
oocyte is nucleated; nucleolus within nucleus; flattened follicular cells; stroma cells irregular, scattered around follicle
what effect do follicular cells have on 1o oocyte?
arrest it in prophase of meiosis I
when do granulosa cells appear/what do they replace
early primary follicle; are cuboidal shaped; replace flattened follicular cells
when does zona pellucida form for first time
late primary follicle
how are cells in late primary follicle
organized; matters because stroma becomes the theca
when does antrum of follicle appear during oogenesis
secondary follicle, when granulosa cells loosen and form pockets of space
when does theca become organized
secondary follicle
what is diff between theca interna and externa
theca interna: cellular rich, produces steroids, clear cytoplasm
theca externa: fibrous rich arrangement
characteristics of oocyte in mature graafian follicle
oocyte located to one side - excentrically located; surrounded with granulosa cells, corona radiata, antrum enlarged
when during fetal development does 1o follicle develop by
7th month
this encapsulation arrests the 1st meiotic division; no further development until sexual maturity
primary follicle cells are
cuboidal granulosa cells
proteins of the zona pellucida
glycoprotein & acid proteoglycans ZP1, ZP2, ZP3
what contributes to zona pellucida formation
both the granulosa cells & oocyte
what is liquid within the antrum called, what does it contain
liquor folliculi, FSH and estrogen
what are antrum nutrients
steroids, pituitary hormones, local growth factors
cumulus oophorus
cluster of cells surrounding oocyte in ovarian follicle and after ovulation; innermost layer of these cells is corona radiata
hormonal action on graafian follicle
LH increase interacts w/ receptors on granulosa and theca cells
what happens to granulsoa cells in graafian follicle
depolymerization of mucopolysaccharides in antrum fluid and increase in colloid osmotic pressure > granulosa cells less adhesive, cumulus loosens
what is the stigma
specific site on ovary surface where follicular wall breaks down; get decreased blood flow, thinning, depolymerization of CT
where is plasminogen activator from, what is its significance?
LH stimulates granulosa cells of graafian follicle to produce plasminogen activator; it cleaves plasminogen to plasmin, acts on follicle wall, causing rupture > 2o oocyte extruded with corona radiata of granulosa cells
what is extruded/where to at ovulation
2o oocyte, zona pellucida, corona radiata, into peritoneal cavity
how is estrogen produced
theca interna cells produce estrogen precursor; granulosa cells of theca externa convert it to estrogen
hypothalamic-pituitary-ovary axis - how it works
hypothal. produces GnRH > acts on pituitary, produces FSH > acts on developing follicles > when enough estrogen from follicles, positive feedback to produce LH & negative feedback to hypothalamus > ovulation occurs as production of LH increases
what hormones act on the corpus luteum of pregnancy
estrogen and progesterone
what does LH due after ovulation
causes granulosa cells to become granulosa lutein cells and theca interna cells to become theca lutein cells aka corpus luteum
what is in early corpus luteum
blood clot from ruptured follicle that released the 2o oocyte
what is corpus albicans
an involuted corpus luteum because not fertilized
what does corpus luteum of pregnancy secrete, why
progesterone and estrogen to prepare endometrial lining for implantation
if no fertilization, what happens to corpus luteum
corpus luteum involutes, becomes large corpus albicans, which disappears after 14 days
what does placenta do re: corpus luteum
eventually takes over estrogen and progesterone production
what are 2 cell types of corpus luteum, what do they produce
granulosa lutein cells: produce progesterone
theca lutein cells: produce estrogen precursor
what is corpus albicans made of
inactive fibrous tissue mass; any remaining cells eaten by macrophages
how many follicles reach maturity
300-400 over 30 yrs reproductive life
what is atretic follicle
dying follicles, wehreby zona pellucide folds up on itself
occurs anytime- birth, puberty, pregnancy
estrogens functions
1) promotive development/maintenance of female reproductive structures, feminine 2o sex characteristics, breasts
2) increase protein anabolism
3) lower blood cholesterol
4) moderate levels inhibit release of GnRH, FSH, LH
progesterone functions
1) works with estrogens to prepare endometrium for implantation
2) prepares breasts to secrete milk
3) inhibits release of GnRH, LH
relaxin functions
1) inhibits contractions of uterine smooth muscle
2) during labor, relaxes pubic symphysis, dilates uterine cervix
inhibit functions
inhibits release of FSH and (lesser but also) LH
what initially secretes estrogens
growing ovarian follicles
what ultimately secretes estrogen, also progesterone, inhibin
developed follicle
what secretes progesterone, estrogens, relaxin, inhibin once developed oocyte
corpus luteum
when blastocyst implants, what reaches up into endometrium
cytotrophoblasts > synciotrophoblasts
main functions of oviduct
1) transport germ cells
2) capacitation of sperm, fertilization of 2o oocyte
3) transport of zygote
how long does it take sperm to get to distal end of oviduct
5 minutes after ejaculation
how many sperm enter the vagina vs how many reach oviduct
250 million enter, 50 or less reach oviduct
what is faster- sperm or oocyte transport?
sperm
what is the shape of the uterine lumen
tortuous
reason for why might be difficult for sperm to reach oviduct
structure of ampulla
muscle outside, mucousal folds project into lumen = mucus membrane w/ epithelium, lamina propria
what type of cells on surface of ampulla
columnar
cell type in oviduct
1) simple columnar ciliated epithelium - aids sperm transport up through isthmus
2) nonciliated secretory cells
how long is mature uterus
7 cm
what is structure of canal of the certix?
endocervix- area between internal os, external os
ectocervix- area outside external os, communicates w/ vagina
what is sloughed off during menstruation
material from endometrial glands in uterus
layers of uterus
endometrium (glandular), myometrium (muscle)
cell type- surface epithelium of endometrium?
pseudostratified ciliated columnar, some cells w/ microvilli
what is endometrium composed of
glandular mucousal part of uterus
stratum functionalis, which has stratum compactum and stratum spongiosum, + stratum basalis
muscle type/number of layers in myometrium
3 layers of smooth muscle
stratum vasculare
middle layer of myometrium, has large blood vessels
functional layer of endometrium
stratum functionalis
shed during menstruation every month
basalar layer of endometrium
stratum basalis
retained, regenerates functional layer every month
what controls uterine cycle
estrogen, progesterone
phases of uterine cycle
1) menstrual phase: 4-5 days
2) proliferative phase: 6-14 days
3) secretory phase
4) ischemic phase
5) menstrual phase
what happens during proliferative phase
endometrium regenerates, 2x-3x thickness, under estrogen control produced by maturing ovarian follicles
what happens during secretory phase
endometrium thickens, under progesterone and estrogen influence produced by corpus luteum
what happens during ischemic phase
if no fertilization
caused by decline in corpus luteum and drop in hormones
what happens during menstrual phase
functional layer undergoes episodes of hypoxia, b/c interruption of blood supply
what happens to blood vessels, stroma, glands as endometrium proliferates?
blood vessels grow, stroma grows, glands become like little corkscrews for secretion
what marks onset of secretory phase
ovulation
what happens to glands over secretory phase
glands visible, glycogen needed for implanted blastocyst nourishment visible, basally located > midsecretion, glycogen moves up gland, apically located > goes to lumen later in phase
shape of glands ultimately
late secretory phase, glands = little corkscrews (began as straight)
blood supply to uterus
uterine artery > myometrium
shape of arteries in endometrium
spiral
shape of arteries in stratum basalis
straight
what happens to arteries during menstrual cycle
as endometrium proliferates, spiral arteries grow, kink, buckle
when progesterone/estrogen withdrawn, arteries grow and buckle in constrictions, capillaries at surface also buckle, bleeding occurs b/c spiral arteries STRONGER than stromal cells can accommodate
what shape are endometrial glands during proliferative phase
straight
estrogen influence
what shape are endometrial glands during early secretory phase
little corkscrewes
shape of endometrial glands late secretory phase
corkscrew
days 15-28
increased progesterone
structure of endocervix
lined w/ simple columnar, mucus-secreting cells
how does mucous of endocervix change over cycle
around ovulation, mucus thin/watery, under estrogen control for easy sperm migration (estrogen)
after secretion, fluid viscous, helps lubricate vagina (progesterone)
where do most cervical cancers arise, why
95% at squamo-columnar junction or TRANSFORMATION ZONE of the cervix
as age, more of endocervix exposed to acid pH (=5) of vagina, area healed by squamous metaplasia process, this makes cells more susceptible to papilloma virus > cancer
structure of vagina
tube, lower end of birth canal
lining: stratified squamous epithelial tissue
no glands, moistened by endocervical mucous
fibroelastic lamina propria
layer of circular smooth muscle
skeletal muscle at vaginal orifice
what does vaginal epithelium make
glycogen, in response to estrogen
secretion metabolized by bacteria into lactic acid
what is different btwn inactive, active mammary glands
structure of ducts
what happens to alveoli from nonpregnant > pregnant > lactating
no lactation: are quiescent, undifferentiated, duct system inactive
pregnant: alveoli grow larger, proliferate at ends of ducts
lactating: fully differentiate, milk secretion abundant
what type of cells in mammary glands
myoepithelial cells
pregnant woman breast tissue contains
many secretory lobules, under estrogen, progesterone, lactogenic hormone influence
what stimulates milk production
suckling sends afferent impulses to hypothalamus; peroventricular neurons cause release of oxytocin, prolactin from axon terminals in pituitary; stimulates milk production and ejection, colostrum, proteins, lactose, vitamins, immunoglobulins
what fill with milk in lactating mammary gland
alveoli
how are proteins of colostrum/milk secreted
exocytosis - merocrine secretion
how are milk lipids secreted
apocrine mechanism - have membrane
how is mammary gland during menopause
glandular looking surface with no active glands, lots of CT, no regularity, lots of fat
aberrant implantation results in
ectopic pregnnacy
PID caused by
pelvic inflammatory disease
chlamydia, gonorrhea
what is endometriosis
ectopic occurence of endometrial tissue b/c of retrograde flow of blood, endometrial tissue - bounds bowels of GI system together
