m1 + 2 lab - cells, life cycles and proliferation Flashcards
what are the two cell differentiation types?
mitosis and meiosis
what is mitosis?
cell division
what is the purpose of mitosis?
replacement, repair, and growth
what are the cell types in mitosis?
somatic cells (“soma” means body)
ex.) epithelium tissue
- muscle tissue
- connective tissue
- nerve tissue
what tissues are amitotic?
- nerve cells
- cardiac muscle
- skeletal muscle
what is the purpose of meiosis?
procreation
- genetic variation
what cells are used in meiosis?
gametes/ sex cells
what are outcomes that can happen if a cell does not go through the normal cell life cycle?
- cell dies
- cell turns cancerous
what is the process of meiosis?
Meiotic Division 1
- begins with replicated DNA (4n)
- cell division occurs (each become 2n)
Meiotic Division 2
- each cell of 2n divides through a second cell division, producing 4 haploids (n or 23 chromosomes each)
what is synapsis?
alignment of the homologous pairs at the cell equator – forming “tetrads”
in Prophase M1, maternal finds paternal
what is a crossover (genetic recombination)?
one chromatid segment of a homologous chromosome exchanges positions with another chromatid (crossing over, forms chiasma)
chromatids break off, those ends join their corresponding (new) chromosomes
what is spermatogenesis?
the process through which sperm cell production occurs
where does spermatogenesis occur?
seminiferous tubules
what is the name of the stem cell used in spermatogenesis?
spermatogonia
pathway of spermatogenesis?
spermatids from spermatogonia mature in the Epididymis then spermiation occurs —> shedding of everything unnecessary
- begins at puberty
- ends at death
what are the hormones used in spermatogenesis?
FSH and testosterone
where does oogenesis occur?
ovary
what is the name of the stem cell used in oogenesis?
oogonia
pathway of oogenesis?
- begins at 8th month of gestation
- stops at Prophase of M1
- starts again at puberty w/ only a few at a time due to FSH and LH
- matures with the follicles
process is not complete until it is fertilized
what happens in Metaphase M2 of oogenesis during puberty?
the oocyte is ovulated
how many sperm do males produce?
4 sperm, two X and two Y
how many eggs do females produce?
only 1 viable egg, the other three sets of DNA are discarded
helps to increase survivability of the infant
what does the hormone GnRH do to the anterior pituitary gland?
causing it to secrete FSH and LH - which target the ovaries
what does follicle stimulating hormone (FSH) do?
oogenesis follicular development
what does luteinizing hormone (LH) do?
stimulates ovulation hormone release
- estrogen and progesterone
what do interstitial cells do?
produce testosterone
what do sustentacular (sertoli) cells do?
nourish and protect the sperm
what happens to sperm in the epididymis during spermiation?
sperm:
- matures
- stored
- reabsorbed
what does capacitation do?
sperm need to mix with PSA (prostate specific antigen) to activate
how many chromosomes do gametes contain?
23 chromosomes (not in pairs)
what are the parts of a sperm cell?
head
- acrosome –> enzymatic covering
- nucleus –> n = 23
midpiece
tail
what do estrogen and progesterone control?
menses (menstruation)
what is the ovarian cycle?
28 day cycle controlled by FSH and LH
- produces secondary oocyte and estrogen/progesterone
phases of the ovarian cycle?
follicular phase - day 1-13
ovulation phase - day 14
luteal phase - day 15-28
what happens in the follicular phase (day 1-13)?
primordial follicles are activated —>
becoming primary follicles (cuboidal epithelium => secretes sex hormones) —>
becomes secondary follicles that release rising amounts of estrogen - helps endometrium redevelop
follicle develops into large fluid filled Graffian Follicle (cuboidal cells surrounding oocyte are called Corona Radiata
what happens in the ovulation phase (day 14)?
sudden increase in LH causes ovulation —> expelling the oocyte into the peritoneum (may cause Mittelschmerz pain)
what happens in the luteal phase (day 15-28)?
- after ovulation, left over granulosa cells form the Corpus Luteum (Yellow Body)
- when Corpus Luteum forms —> produce progesterone to maintain the endometrium
what happens in the luteal phase if implantation occurs?
it will continue 90 days until the placenta takes over production
what happens in the luteal phase if implantation does not occur?
the Corpus Luteum will degenerate in 10 days —> leads to menses
there will be a small scar called Corpus Albicans (White Body)
phases in the uterine cycle?
1) menstrual phase
2) proliferative phase
3) secretory phase
controlled by production of estrogens and progesterones
what happens in the menstrual phase (days 1-5)?
menses -> menstruation
endometrium sheds *** this occurs when progesterone levels drop to their lowest levels
what happens in proliferative phase (day 6-14)?
- endometrium redevelops due to rising levels of estrogen
- mucus is thin and watery to allow passage of sperm into the uterus
- day 14 - ovulation occurs due to LH
what happens in the secretory phase (day 15-28)?
- endometrium prepares for implantation of egg
- levels of progesterone rise => functional layer becomes mucosal layer, acts as a mucus plug in Os of cervix
what system causes erection/arousal?
parasympathetic system
orgasm is caused by:
sympathetic system
ejaculation occurs by:
bulbospongiosus muscle contractions
fertilization occurs where in the fallopian tube?
ampulla
a blastocyst:
is implanted into the endometrium in about 7 days
- after implantation, production of HCG occurs
HCG:
Human Chorionic Gonadotropin
- indicates pregnancy
- maintains Corpus Luteum
what happens in the embryonic stage?
- placenta attaches to the endometrium
- amniotic sac
-embryo develops in the first 8 weeks of gestation
what does the placenta provide?
- location of nutrient diffusion, waste removal and oxygenation of the fetal blood
- produces HCG and then progesterone (which maintains the pregnancy)
