WEEK THIRTEEN - Female reproductive anatomy Flashcards
Identify and describe the main anatomical features of the ovaries
female gonads = ovaries
- almond shaped organ nestled in **ovarion fossa **- posterior pevlic wall
- 3cm long x 1.5cm wide x 1cm thick
- encapsulated by fibrous **tuninca albuginea **
- consists of
INNER MEDULLA - fibrous CT filled w/ principal arteies and veins
OUTER CORTEX [site of ovarian follicles]
- each follicle contains oocyte
- in childhood, ovaries = smooth
- during reproductive years –> become corugated due to bulging growing follicles
- after menopause, ovaries = shrunken/composed mostly of scar tissue
- help up by suspensory ligaments which also allow arterial/venous/lymphatic/nerve circulation through ovaries
Identify and describe the main anatomical features of the uterine tubes
uterine tubes/fallopian tubes/oviducts
- 2x10cm tubes leading from ovaries –> uterus
- near uterus, tube forms a narrower isthmus
- ampulla = middle/longest part of tube
- ends in funnel shape with ciliated infundibulum with fimbriae
- receive the ovulated oocyte and provide site of fertilisation [normally in ampulla]
- tubes = NO physcial connection of ovaries - the cilia beat on fimbriae → carries oocytes to uterine tubes → peristaltic action of tubes carry oocyte to uterus
Identify and describe the main anatomical features of the uterus
- Pear shaped muscular organ
- Cervix at inferior end [cervical glands secrete mucus with block sperm entry except during mid cycle
- uterus angle
anterverted position (75% women), uterus tips forward from the cervix
Retroverted position [tilts posterior] = fairly common - 25% of women
THREE layers
1. OUTER perimetrium
- serous layer; visceral peritoneum
- MIDDLE myometrium
- interlacing smoo.musc layers - INNER endometrium
- Mucosal lining of uterine cavity [simple columnar epithelium]
- uterine glands = change in lengh as endothelium thickness changes
- FUNCTIONAL LAYER = stratum functionalis [undergoes cyclic shedding/ changes from ovarian hormones
- BASAL LAYER = stratum basalis
- forms new functionalis layer after mesntruation ends
Identify and describe the main anatomical features of the vagina and external genitalia
vagina
- 8-10 cm tube w/ rugae [expansion/sexual stim]
- allows for receipt of semen/penis
- THREE LAYERS
1. OUTER adventitia
2. MIDDLE muscularis
3. INNER mucosa
- lubricated by transudation of serous fluid
- during puberty estrogen converts childhood simp.cub.epi –> strat.squa.epi
external genitalia
mons pubis
- round fatty area over pubic symphysis
labia majora
- alongated, hair covered fatty skin folds [homologous to scotum]
labia minora
- hair free skin folds within labia majora
- homologous to M urethra
greater vestibular glands
- keep vestibule moist and lubricated
- homologous to bulbourethral glands
- pea sized glands flanking vagina
clitoris
- grows w age
- erectile tissue hooded by prepcue
- exposed portion = glans
- homologous to penis
List the principal signs of puberty in the female
^ GnRH lvls stim ant.pit to produce LH + FSH = PUBERTY BEGINS ~9 yo
- stim follicle development = esto.progesto secretion = development of secondary sex characteristics
1ST STAGE
- thelarche
- development of breasts
2ND STAGE
- pubarche
- growth of pubic and axillary hair, apocrine and sebaceous glands
3RD STAGE
- menarche
- FIRST menstrual cycle
- requires at least 17% BF in teen/ 22% in adult
- brain monitors lvl of BF through leptin
- leptim stims gonadotropin hormone
- average age of onset = 12 [improved nutrition –> ^ BF]
List the actions of the ovarian hormone estrogen
- promotes oogenesis and follicle growth
- anabolic effects pf female reproductive tract
uterine tubes, uterus and vagina grow larger and become functional
uterine tubes and uterus exhibitit enhanced motility
vaginal mucosa thickens
external genitalia mature - development of secondary sex characteristics
breast growth, ^ deposition of subcutaneous fat in hips/breast
widening of pelvis
growth of axillary/pubic hair - helps preserve bone density
- feedback regulation of GnRH and gonadotropins, behaviour, neurprotection of brian
- renal = ^ Na+ and water reabsorption
- regulates HDL levels for cadiovascular health
List the actions of the ovarian hormone progesterone
-thickens endometrium for potential implantation
- quietens myometrium
- thicker cervical mucus
- breast development
- increases body temp
- diuresis
State what triggers menopause and list the physiological changes that result from menopause
loss of ovarian hormone production = cessation of mestruation [avg age = 52]
few follicles remain with age = reduced estrogen/progresterone secretion and sensitivity to gonadotropic homrones
**decrease in FSH ** = reduced hormone cells/receptors
results
- reductions in estro.progesto steroids = atrophy of uterus, vagina, breasts
- skin = thinner, bone mass decreases and risks of cardiovascular disease increases [due to loss of HDL]
- blood vessels constrict and dilate in resposne to changing hormone levels and sudden dilation of cutaneous arteries = hot flushes several times/day
Oogenesis; description of its process, with cells produced and its timing
ogenesis occurs in stages over many YEARS = COMPLETE only if fertilised, otherwise restarts every month
**fetal stage
**- 5-6 wks primordial germ cell **[PGC] > mitosis > oogonia **
- oogonia multiply to **6-7mill until 5mth **month of gestation then arrest until shortly BEFORE BIRTH
- before birth -6mth after = oogonia die or transform into primary oocytes which begin meiosis I but **stall in prophase I **until puberty
- at **birth = 2 mill **primary oocytes
puberty
- after puberty, each menstrual cycle –> primary oocyte –> **completes meiosis I **–> 2 haploid cells - [first polar body+secondary oocyte]
- secondary oocyte arrests in metaphase II and is ovulated
- penetrated by sperm, the second oocyte completes meiosis II creating a second polar body
mid gestation = 6-7 mill oogonia
- birth = 2 mill oocytes
- puberty = 400,000 oocytes
- reproductive years = 400 oocytes
» oocyte atresia by apoptosis [programmed cell death]
State the names of the different types of follicles formed during folliculogenesis and describe any major differences
PRIMORDIAL FOLLICLE
- One layer of FLATTENED follicular cells surrounding oocyte
PRIMARY FOLLICLE
- One layer of CUBOIDAL follicular cells around oocyte
SECONDARY FOLLICLE
- MULTIPLE layers of GRANULOSA and THECAL cells
Has fluid-filled space between granulosa cells = forms central antrum
TERTIARY FOLLICLE
- GRANULOSA cells secrete follicular fluid
Fluid = accumulates in pools within follicle = forming central antrum
MATURE [GRAAFIAN] FOLLICLE
- MOST mature stage
BULGES from surface of ovary
CORPUS LUTEUM
- Ruptured follicle AFTER ovulation
Name the 3 phases of the ovarian cycle and describe what happens in each stage?
- follicular phase [D1-14]
- FSH stims growth of primoridial follicle > primary follicle > secondary > tertiary
- thecal/granulosa cells cooperate = produce **estrogen = forms antrum **
- tertiary –> graafian follicle = antrum expands/bulges from external surface of ovary
- primary oocyte completes meiosis I –> secondary oocyte ready for ovulation - ovulation [D14]
- Follicular fluid builds → further swelling of follicle → rupture of mature follicle and release of the egg
- 1-2% of ovulations release more than one secondary ooc.
If fertilized = fraternal twins!!
- after ovulation rupture follicle collapses, granulosa/thecal cells enlarge = corpus luteum - luteal [D14-28]
- Corpus luteum secretes progesterone/estrogen
- No pregnancy = corpus luteum degenerates in 10 days leaving a scar [corpus albicans]
- Pregnancy = corpus luteum produces hormones until placenta takes over the role at ~3mths
Describe the hormonal interactions during each phase of the ovarian cycle
- follicular phase [D1-14]
- maturing follicle secretes estrogen –> stims hypothal
- hypothal –> GnRH +estrogen –> ant.pit –> LH + FSH
- LH +FSH = follicle growth/maturation / low level estrogen release
- oocyte compltes meiosis I = follicle enlarges –> ovulates - ovulation [D14]
- mid cycle LH surge
- stims primary oocyte to complete meiosis I then secondary oocyte –> metaphase II
- triggers ovulation
- transforms ruptured follicle –> corpus luteum [produces inhibin, proges, estrog - luteal [D14-28]
- Progesterone + estrogen = STRONG negative feedback → **INHIBIT FSH + LH release **
- declining LH levels = ends luteal activity
- days 26-28 [DECLINE of ovarian hormones]
- ends blockafe of FSH/LH secretion and cycle starts again
State and describe the 3 stages of the menstrual (uterine) cycle and explain how they are regulated by estrogen & progesterone
- menstrual [D1-5]
- low levels of estrogen/progestrone = deprive hormonal support to endometrium
- spiral arteries kink and spasm = endometrial cells begin to die/functional layer digests itself
- spiral arteries constrict one last time before relaxing –> rush of blood weakens capillary beds and functional layer sheds
- **shedding of basalis functionalis ** - proliferative [D6-14]
- HIGH Estrogen = stims mitosis in stratum basalis + regrowth of blood vessels = generates stratum functionalis **
- endometrium rebuilds ** - secretory [D15-28]
- HIGH levels of progesterone to stim THICKENING of endometrium further due to ^ fluid accum./secretion
- endometrium **preps for implanation of embryo **
State some physiological changes that occur during the female sexual response
unstimulated
- uteris tilts forward over bladder
- vagina relatively narrow
- labia minora retracted
excitement
- uterus stands more superiorly
- **inner end of vag dilates **
- labia minora vasocongested [may extend beyond majora]
- minora may become red [hyperemia]
- vaginal **transudate moistens **
plateau
- uterus tented/erected
- cervix withdrawn from vagina
- orgasmic platform [lower 1/3 of vag] constricts penis
- clitoris engorged and glans withdrawn beneath prepuce
- labia red
orgasm
- orgasmic platform contracts rhythmically
- cervix may dip into semen pool
- uterus - **peristalstic contractions **
- anal and urinary sphincters constrict
resolution
- uterus - restin position
- orgasmic platform relaxes
- inner end of vag constricts - returns to original dimensions
Describe how fertilisation occurs?
sperm transported by **swimming + smoo.muscular peristalstis of female tract **
- oxytocin released during intercourse ^ smoo.musc activity in uterus
- mortality v large due to acid envronment and length of trip [40-200 sperm reach uterine tubes]
