reproductive system Flashcards
what are the parts in the external genitalia of the male anatomy
penis, scrotum
what are the parts in the gonads of the male anatomy
testis
what are the parts in the internal genitalia of the male anatomy
vans deferens, epididymis, ejaculatory duct, seminal vesicle
describe if testis occurs in single or pair, its location and function
pair
located in scrotum
produces sperm and testosterone
describe if epididymis and ductus deferens occur in single or pair, its location and function
pair
one epididymis attached to rear of each testis, one ductus deferens travel from each epididymis up and out of scrotal sac through the inguinal canal to the urethra at neck of bladder
serve as sperm exit route and site of maturation for motility and fertility
describe if seminal vesicle occur in single or pair, its location and function
pair
empty into last portion of ductus deferens
supply fructose to nourish ejaculated sperm, secrete prostaglandins to stimulate motility to help transport sperm and provide bulk to semen
describe if prostate gland occur in single or pair, its location and function
single
completely surround urethra at neck of bladder
secretes alkaline fluid to neutralise acidity of vagina, trigger clotting of semen` to ensure sperm stays in vagina even after penis removal
describe if bulbourethral gland occur in single or pair, its location and function
pair
empty into urethra
secrete mucus for lubrication
when does descent of testes occur
during puberty
when does descent of testes finish
usually by 7th month of gestation
why does descent of testes occur
role of testosterone from fetal testes
what occurs during descent of testes
shortening of gubernaculum
what is gubernaculum
cord of muscle
what is cryptorchidism
undescended testes into adulthood resulting in the inability to produce viable sperm
temperature of scrotum for spermatogenesis to occur
35 degrees C
how long does spermatogenesis take
64 days and does not occur synchronously in the seminiferous tubules
what are the two cells located in the seminiferous tubules
sertoli and leydig cells
what is the function of sertoli cells
produce nutrients for sperm cells to grow and mature
what is the function of leydig cells
produce testosterone
what occurs during puberty
onset of spermatogenesis, enlargement of testes and development of secondary characteristics, hormonal changes
what hormone is produced by the hypothalamus during puberty
gonadotropin releasing hormone (GnRH)
what does GnRH regulate
regulate secretion of FSH and LH from the anterior pituitary
what does FSH target
sertoli cells to release nutrients for sperm growth
what does LH target
leydig cells to release testosterone
what role does testosterone have
negative feedback on the hypothalamus
what happens if there is continuous exposure of gonadotrophs to GnRH
desensitisation of GnRH receptors
what are the effects of testosterone
internal male genitalia, pubertal growth spurt, penis growth, deepening of voice, spermatogenesis, libido, muscle growth
what hormone does leydig cells produce from cholesterol
cholesterol -> progesterone -> testosterone
what hormone does sertoli cells produce from testosterone and using which enzyme
testosterone -> dihydrotestosterone using 5alpha enzyme
what are the effects of dihydrotestosterone
external male genitalia, sebaceous glands, male hair pattern, male hair pattern baldness
what hormones do testis produce
androgens, MIF, inhibin, ABP
what are androgens
any steroid hormone that promotes male secondary sex characteristics
what are examples of androgens
testosterone and DHT
which parts of the female anatomy are part of the external genitalia
vagina (lower 2/3), clitoris, labium major, labium minor
which parts of the female anatomy are part of the gonads
ovary
which parts of the female anatomy are part of the internal genitalia
uterine duct, uterine tube, uterus (myo, peri. endometrium), vagina (upper 1/3), cervix
what is the function of the ovary
site of storage and development of oocyte, secrete sex hormones like estrogen and progesterone to promote fertilisation of ovum and prepare female tract for pregnancy
what is the function of the oviduct
for transporting of oocyte from ovary to uterus
what is the function of the uterus
hollow chamber for development of embryo, responsible for maintenance of fetus during development, expelling of fetus at end of pregnancy, responsive to female hormones
what is the function of the cervix
lower part of uterus that opens into vagina
what is the function of the vagina
to produce lubricating fluids, birth canal
what is the function of the clitoris
organ of sexual arousal
describe the process of estrogen synthesis
LH binds to LH receptors to cause secondary messenger system and signal amplification which results in cholesterol converting into a precursor required for FSH to produce estradiol (estrogen)
how long does an ovarian cycle last
28 days
what are the two alternating phases in an ovarian cycle
follicular and luteal phase
apart from production of FSH what does FSH play a role in
follicular growth and maturation and induces antrum formation where estrogen is stored at
at puberty which hormone level rise and what does it result in
GnRH which causes LH and FSH secretion
what are the stages of ovarian cycle
rising moderate level of estrogen -> rising high levels of estrogen and follicle maturation -> massive increase in LH -> follicular phase -> luteal phase -> formation of corpus luteum -> degeneration of corpus luteum
what occurs during rising moderate level of estrogen
negative feedback on hypothalamus to inhibit GnRH secretion, production of inhibin by follicular cells which selectively inhibit secretion of FSH leading to continuous increase in LH levels
what occurs when there is rising high levels of estrogen and follicular maturation
positive feedback on hypothalamus to increase GnRH secretion and selectively stimulate LH secretion, but inhibin secretion from follicular cells continue to inhibit FSH secretion resulting in a surge in LH levels
what occurs when there is a massive increase in LH
differentiation of follicular cells into luteal cells and ovulation
what occurs in the follicular phase
dominated by presence of maturing follicles
what occurs in the luteal phase
presence of corpus luteum
what occurs during development of corpus luteum
under influence of LH, corpus luteum secretes both estrogen and progesterone, P inhibits secretion of both LH and FSH which prevents new follicular maturation and ovulation prevented
what occurs during degeneration of corpus luteum
if no fertilisation occurs, CL degenerates and E and P no longer produced as not required, negative feedback on hypothalamus inhibited which promotes increase in GnRH secretion for new follicular phase to begin
what is corpus luteum
remnant of matured follicle
what are the phases the endometrium goes through
menstrual, proliferative, secretory
are the levels of P and E high or low in menstrual phase
low
what occurs during proliferative phase
E helps to grow follicular cells and stimulate growth of uterus (glands and blood vessels grow), endometrium thickens gradually
when does secretory phase start
starts once E converted to P and egg released
what occurs during secretory phase
glands in uterus secretes nutrients in preparation for baby, if no hormone produced to stimulate positive feedback, no fertilisation and low hormones prevents uterus from being nourished resulting in sloughing
what does P do during secretory phase
increase number of blood vessels and secretory glands in endometrium
what are the effects of puberty
thelarche (enlargement of breasts), pubarche (growth of pubic and auxillary hair), menarche (first menstrual period), rapid increase in height, growth of secondary sex organs, fat deposition
compare the hormones produced by hypothalamus between male and female
both GnRH
compare the hormones produced by anterior pituitary
both FSH and LH
what are the hormones produced by ovaries and specifically by which cell
estrogen and inhibin by granulosa cells, progesterone by CL, androgen by theca cells which would then be converted to estrogen
compare the target/ endocrine cells between male and female
male: sertoli, leydig
female: granulosa, CL
compare the hormones between male and female
male: T, DHT, inhibin
female: P, E, inhibin
why does menopause occur
ovaries have fewer remaining follicles, less responsive to GnRH thus secrete less E and P
what are the effects of menopause
cessation of menstrual cycle, skin changes, gradual atrophy of genital organs, vasomotor changes (regulation of blood vessel dilation and constriction which can cause hot flushes), psychological and emotional effects, increase risk of CVD due to increased levels of cholesterol, increase risk of osteoperosis due to decreased bone mass due to decreased E
