L24-25: Reproductive Systems Flashcards
male primordial germ cells
migrate into future testes and become spermatogonia
spermatogonia
begin mitotic division at puberty and become primary spermatocytes
primary spermatocytes
complete the first half of meiosis and become 2ndary spermatocytes
secondary spermatocytes
complete the 2nd half of meiosis and become spermatids
spermatids
undergo differentiation to become mature sperm
sertoli cells
located in seminiferous tubules
act as nurse/Sustentacular cells by surrounding primary spermatocytes and nursing them thru spermatogenesis and spermiogenesis
form estrogens from testosterone
—which is thought to be important for spermiogenesis
spermiogenesis vs spermatogenesis
differentiation of spermatids into mature sperm
vs
generation of sperm
sertoli cells – layers
mature spermatids immature spermatids secondary spermatocyte primary spermatocyte sertoli cell nucleus spermatogonial cell BM
list order of cell division during spermatogenesis
primordial germ cell spermatogonia 1 spermatocyte 2ndary spermatocyte spermatids (tail-less) mature sperm (tail)
list the structures of mature sperm from head to tail
acrosome surface memb vacuole ant head cap post head cap neck body w/ mito chief tail piece end piece of tail
acrosome
contains hyaluronidase and proteolytic enzymes
caps nucleus
where is sperm stored?
in the epididymis until ejaculation
must remain in epididymis for 18 to 24 hours in order to gain motility – passing thru epi takes several days
cells of leydig
found in interstitial spaces in testes
secrete testosterone
stimed by luteinizing hr secreted by ant pit
(FSH is also necessary for spermatogenesis)
seminal vesicles – properties
paired structures behind prostate secrete mucoid materials: --fructose --citric acid --additional nutrients --prostaglandins --fibrinogen
male accessory glands
seminal vesicles
prostate gland
seminal vesicles – during emission and ejaculation
contents of vesicles are emptied into ejaculatory ducts containing sperm
60% of vol = semen
fructose gives nrg for sperm
prostaglandins in seminal vesicles – function
make cervical mucous more receptive to sperm mvt
and
may cause retro-peristaltic contractions of uterus and fallopian tubes
prostate gland – during emission and ejaculation
30% of vol = semen
milky fluid containing:
- -Ca
- -citrate ions
- -phosphate ions
- -clotting enzyme
- -profibrinolysin
slightly alkaline – to help neutralize the acidity of other seminal fluid and vagina
define androgens
any steroid hormone that has masculinizing effects
- -testosterone
- -dihydrotestosterone
- -androstenedione
synthesized in testes and adrenal glands from:
cholesterol
acetyl-CoA
testosterone – formed by interstitial cells of leydig
cells numerous in newborn and adult males
–nonexistent during childhood
post secretion:
circulate in blood 30m - hours
transfer into tissues or degraded
testosterone that enters tissues
mostly converted to dihydrotestosterone
especially in prostate and fetal external genitalia
testosterone that is not fixed in tissues
converted in liver to:
androsterone and dehydroepiandrosterone
conjugated as either glucuronides or sulfates
excreted into gut via bile or urine (via kidneys)
functions of testosterone
- masculine characteristics
- descent of testes
- genitalia enlargement
- 2ndary sex characteristics
- male pattern baldness
- hypertrophy of larynx
- skin thickness
- increased sweating
- increased protein formation and muscle growth
- increased BMR, hematocrit, Na absorption, bone matrix
gonadotropin releasing hormone – male
= LH releasing hr
produced by neurons located in arcuate nuclei of hypothalamus
–transported to ant pit
stims ant pit to product LH mostly and FSH
luteinizing hormone – males
glycoprotein
activates cAMP in tissues
causes sertoli cells to secrete testosterone
which has a neg feedback on hypothalamus
inhibin – male
secreted by sertoli cells
inhibits secretion of FSH from ant pit
–also inhibits secretion of GnRH to a lesser extent
define oogenesis
a meiotic process that begins during embryonic development and ends w/ the formation of a single haploid oocyte/egg and 3 polar bodies
primordial germ cells – female
develop from germinal epi of indifferent gonad early in embryo
migrate to future ovary site
become oogonia
oogonia
surrounded by single layer of granulosa cells
oogonia + granulosa = primordial follicle
ovum at this point = primary oocyte
describe the primary oocyte characteristics
meiosis arrested at diplotene of prophase I
most primary oocytes become atretic b4 birth
at puberty one oocyte completes meiosis = 2ndary oocyte + polar body
secondary oocytes
arrested at 2nd metaphase stage of oogenesis
meiosis does not finish until fertilization
phases of the menstrual cycle
ovarian phase
- follicular growth 5-14
- ovulation 14
- corpus luteum growth 14-23
- corpus luteum regresses 24-28
uterine phase
- menstruation 1-5
- proliferation 4-14
- secretion 14-28
one menstrual cycle = 28 days
first stage of follicular growth in menstrual cycle
moderate enlargement of the ovum itself 2-3x
growth of granulosa cell layers becoming 2ndary follicles
[FSH] and [LH] increase
fsh is greater and happens first
as FSH and LH levels rise in the beginning of the menstrual cycle ?
growth of multiple follicles w/ multiple layers of granulosa cells
spindle shaped cell surround follicles to form interna and externa theca cell layers
early growth of ovum/follicle is stim most by FSH
theca cells
theca interna
–ability to secrete estrogen and progesterone
theca externa
–protective capsule of developing follicle
granulosa cells
secrete a follicular fluid containing a high conc of estrogen
this causes an antrum to appear
anterior pituitary sex hormones – females
FSH and LH
no secretion as child
combine w/ highly specific receptors on ovarian cells
ovarian hormones
estrogen/progesterone
primordial follicles are surrounded by single layers of ______ cells and throughout childhood these cells ?
granulosa cells
provide nourishment for ovum
–secrete oocyte maturation inhibiting factor that keeps ovum suspended in primordial state
changes in uterus during proliferation stage
estrogen phase
occurs b4 ovulation
endometrium desquamated
only deep cells left
the estrogen causes stromal and epi cells to rapidly prolif
the endometrium surface is restored w/in 4-7 dats after menstruation begins
changes in uterus during secretory stage
progesterone phase
corpus luteum secretes proges/estro in large conc
proges causes swelling and secretory development of the endometrium
results in high secretory endometrium w/ large amounts of stored nutrients to nourish ovum
changes in uterus during menstruation stage
no fertilization
corpus luteum involutes
ceases secretion
lack of proges/estro results in menstruation and involution of endometrium
24 hrs b4 menstruation, BVs become vasopastic causing necrosis of endometrium
effect of estrogen on vagina and fallopian tubes
growth, thickening of walls, increased acidity
growth of thick wall for contractions to transport egg and sperm
estrogen effects on uterus
enhance/maintain mucous memb
increases size of endometrium, enhanced blood flow, protein count and enzyme activity
stim development of uterine muscles
effect of estrogen on mammary glands
growth of breasts during adolescence
pigmentation of nipples
stopping the flow of milk when an infant stops breast feeding
estrogen – secondary sex characteristics
smaller bone size and structure, broad pelvis
increases fat storage around hips/thighs
fine body hair
small voice box
suppress activity of glands in skin
