reproduction; oogenesis + spermatogenesis Flashcards
what is spermatogenesis? where does it take place
process is called during gamete formation, ending with 4 haploid sperm cells
takes place in the testes»seminiferous tubules of male
what does sperm cell end with with its four non identical haploid cells?
have the same number of chromosomes and an equal amount of cytoplasm.
what do each tubule have beneath the enclosed membrane
Each tubule is enclosed in basement membrane» beneath is a layer of germinal epithelium cells/ spermatogonia
germinal epithelium cells
diploid cells that divide (mitosis) regularly which produces more diploids that enlarge, known as: primary spermatocytes
primary spermatocytes divide by
meiosis
primary spermatocytes first division
first neurotic division produce two haploid cell»_space; secondary spermatocytes
primary->secondary spermatocyte second division
secondary spermatocytes produce»_space; four spermatids
sperm dvlpt 1– Sertoli cells
what spermatids attach to, also called nurse cells
assist in differentiation of immature spermatids-> spermatozoa by providing n o u r i s h m e n t
sperm dvlpt 2– what happen when spermatozoa develop tail
once spermatozoa develops their tail, they detach from Sertoli cells and carried down the lumen of tubule—> epididymis
testes
are each testis housed outside abdominal cavity in a sac called the scrotum
testes+scrotum = testicles
how does scrotum need to condition itself to procure sperm?
sperm can’t optimally develop at human body temperature, so it remains 2 degrees cooler
makes muscles around the scrotum to contract pulling testes toward the body.
Sperm is controlled by three hormones
follicule-stimulating hormone (fsh)
testosterones
luteinizing hormone (lh)
fsh male
stimulates meiosis in spermatocytes to produce haploid cells
produce by pituitary gland
testosterones
stimulates maturation of secondary spermatocytes into mature sperm cells
produced by testes (signaled to be made by pituitary gland)
lh male
stimulates the secretion of testosterones by the testes
produced by pituitary glands
What stage is sperm created
puberty stage
how do sperm cells leave epididymis? I
sperm cells are released during ejaculation within a nutrient-rich fluid: semen
semen is mixed with sperm cells as they leave epidiymis
leaves to vas deferens via muscular contractions that propel sperm there
ejaculation
expulsion of semen from penis
vas deferens
A duct that passes upward the abdomen and loops around the urinary bladder which joins a short duct: seminal vesicle
the two ducts unite»_space; ejaculatory duct
what is semen produced by
two seminal vesicles and prostate gland
70% of semen fluid from seminal vesicles is made of what?
70% of semen fluid from the seminal vesicles are rich in fructose» provides energy for sperm to swim and contains mucus to protect the spermatozoa from acidic environment of vagina
prostate gland produces
+bulbourethral glands
alkaline gland»_space; thin fluid that further nourishes the sperm
bulbourethral glands» secretes a clear alkaline mucus
oogenesis 1
gamete formation starts will diploid cells: oogonia/germinal epithelial cells with
o v a r i e s
og 2– what occurs when oogonia divides?
oogonia divides by mitosis and enlarges to form primary oocytes
og 3– primary oocytes 1/2 process
begins meiosis but stops at phase I, leaving primary oocytes surrounded by primary follicles
follicule dvlp 1- what happens during menstrual cycle (2/2 process)
during e/ menstrual cycle a few follicles continue meiosis I but only one will complete it producing»_space; 2 haploid cells
follicule dvlp 1.2- what does menstrual cycle result in
The 2 haploid cells w/:
the division of the cytoplasm will be uneven by the end of meiosis
results in a secondary oocyte and a polar body
^^
whole thing = follicule
follicule dvlp 2- what happens to secondary oocyte
it begin meiosis II but stops at prophase ii
follicle cells also divide and produce a fluid -> cause follicle to swell
follicule dvlp 2.2- what happens during ovulation
at ovulation, causes follicle to rupture and release secondary oocyte
follicule dvlp 3- after fertilization…
secondary oocytes completes meiosis ii -> becomes ovum*
empty follicle dvlps»_space; corpus luteum: produces progesterone
unequal division of cytoplasm during oogenesis provides ovum
w/ enough nutrients to support the dvlping zygote for a few days
menstrual cycle hormones
menstrual cycle is regulated by hormones produced by pituitary gland:
fsh, estrogen, lh, progesterone
fsh female
stimulates follicle inside ovary to dvlp which secretes estrogen
estrogen
stimulates the lining of uterus to thicken + stimulates lh
lh female
triggers ovulation + dvlpmt of the corpus luteum
corpus luteum 1- it produces…
both progesterone and estrogen
corpus luteum 2- progesterone does what? why?
progesterone increases the uterine lining which causes fsh to drop
» prevents the release of another egg until progesterone decreases again
if egg is not fertilized pt 1- what breaks down? resulting in?
the corpus luteum breaks down, resulting in levels of progesterone dropping.
if egg is not fertilized pt 2- what does this drop cause? (2 things)
the progesterone causes uterine lining to break down + menstruation to occur.
if egg is not fertilized pt 3- what continues for 4-7 days, what does it result in?
menstruation continues for 4-7 days until progesterone reaches a certain level causes:
release of fsh by pituitary»_space; cycle starts again
if egg is fertilized pt 1- what happens when _____ is deposited?
sperm deposits goes into female cervix, they travel up uterus -> oviduct
if egg is fertilized pt 2- what happens in the oviducts?
fertilization occurs in oviducts when:
1 sperm enters mature egg»_space; their nuclei fuse»_space; forms a zygote
