week 12 (rep.) Flashcards
(27 cards)
define: fertilization
- fusion of gametes from 2 parents to produce an offspring that as 2n chromo.
- 2 haploids prod. a diploid
define: gametogenesis
- making haploid from meiosis
- prod. gamete
compare: oviparous, viviparous, ovoviviparous animals
- ovi = eggs
⤷ dev. = external
⤷ fert. = internal or external - vivi = young dev. in female
⤷ dev. = internal
⤷ fert. = internal - ovovivi = eggs hatch inside
⤷ dev. = internal and external (when released from mother)
⤷ fert. = internal
explain: oogenesis
- production of female sex cell
- ovary makes eggs
- oogonia undergo mitotic division -> primary oocytes
- primary oocytes undergo meiosis
- some cells die, some stay in prophase I
- oocytes re-enter and complete meiosis after puberty
⤷ 1 egg released each month
explain: spermatogenesis
- production of male sex cell
- testes prod. sperm
- spermatogonia undergo mitosis -> primary spermatocytes
- enter into mitotic arrest until birth
⤷ resume mitosis when born - undergo meiosis at puberty
- continue mitosis and meiosis throughout life
question: if only 1 sperm is needed for fertilization, why is a low sperm count bad for infertility?
- not all sperm make it to the egg
⤷ journey is hard and not optimal envrt. for sperm - more sperm increases opportunity
- need more than one sperm to interact w/ egg to break down ZP
question: what’s considered an infertile sperm count? avg?
- avg = 200 million
- infertile = less than 20 million
explain: purpose of sertoli and leydig cells
- sertoli = secrete luminal fluid
⤷ has nutrients to support sperm dev. (releases ABP to keep testosterone high)
⤷ medium for sperm transport
⤷ in epi. cells surrounding tubule lumen - leydig = secrete testosterone + androgens
⤷ in endocrine cells between tubules
question: where do sperm mature?
- epididymis
⤷ in the seminiferous tubules of the rete testis of the epididymis
question: what does the vas deferens do?
- delivers contents of storage in seminal vesicle
- convergence point of semineferous tubules
explain: structure of a sperm
- head = haploid
⤷ has acrosomal region w/ enz. that breaks down ZP of egg - loses most of it’s cytoplasm
- has midpiece for energy
⤷ has a lot of ATP - flagellum does whip mvt. to “swim”
explain: path of sperm after spermatogenesis
- released into lumen of seminiferous tubules
- travels to rete testes -> efferent ductules -> epididymis
⤷ matures more in epididymis - travels through vas deferens to seminal vesicle, prostate, and bulbourethral gland
- seminal fluid added to sperm by exocrine glands during ejaculation
⤷ seminal vesicle prod. fluid w/ nutrients to protect against acid in vagina
⤷ prostate secretes nutrients
⤷ bulbourethral gland secretes mucus for lube
explain: hormonal regulation for spermatogenesis
- hypothalamus releases gonadotropin-releasing hormone (GnRH)
⤷ binds and causes secretion of FSH and LH in blood - FSH stim. sertoli cells to release androgen binding prot (ABP) to keep testosterone lvls high
- LH stim. leydig cells to secrete testosterone
**increasing testosterone maintains spermatogenesis
**high lvls of testosterone evental inhibit release of GnRH, FSH, and LH (feedback loop)
compare: aquatic animal eggs vs terrestrial animal eggs vs placental animals
AQUATIC
- permeable to water
- fish and amphibians
- eggs do external fert.
TERRESTRIAL
- hardened shells
- internal fert.
- shells are to prevent dehydration
**terrestrial vert. embyros are kept in fluid filled amnion
PLACENTAL
- no egg shell
- dev. the ova internally
explain: dev. of a corpus luteum
- primary oocytes have complete layer of follicular cells (granulosa)
- follicle ruptures -> ovum escapes ovary to coelom
⤷ becomes secondary oocytes - ovum goes to uterus leaving follicle
⤷ empty follicle becomes corpus luteum (produces progesterone)
explain: path of primary oocyte after oogenesis
**primary oocytes stay arrested in prophase I until released each month
⤷ follicle made now
- resumes w/ meiosis I
⤷ 1st division -> secondary oocyte and first polar body - FSH from pituitary causes follicle to enlarge
- LH induces ovulation of egg arrested in metaphase II
⤷ fertilization induces completion of meiosis II
explain: follicular phase
- day 1 - 14
- some follicles dev. but most in primordial phase
- follicle cells become granulosa cells and dev. theca layer
⤷ more FSH and LH -> prod. estrogen
explain: luteal phase
- day 14 - 28
- mature oocyte released and enters uterine tube
- corpus luteum releases progesterone to keep lining of uterus intact if egg gets fert.
question: what happens to corpus luteum if no fertilization?
- corpus luteum breaks down to corpus albicans
- decrease progesterone lvls
- triggers menstruation
explain: hormonal changes in the ovarian cycle
- GnRH triggers FSH and LH
- peak LH and FSH triggers ovulation
⤷ high estrogen low progesterone - LH peak also causes follicle-> corpus luteum
⤷ releases progesterone and estrogen (increase)
⤷ lvls drop again if no pregnancy
explain: purpose of corpus luteum
- increases estrogen and progesterone
- progesterone prevents ovulation and inhibits LH
⤷ prevents second egg from being ovulated - if corpus luteum degenerates -> drops in estrogen
⤷ progesterone increases -> triggers menstruation
explain: phases of uterine/menstruation cycle (3)
- menses
- 1 - 7 days
- shedding the functional zone - proliferative phase
- basilar zone is regenerating func. zone
- rising lvls of estrogen
- ovulation happens at the end of the phase (LH surge) - secretory phase
- impending possible fertilized egg
**proliferative phase = same time as follicular phase
question: ovarian cycle vs uterine cycle?
OVARIAN
- follicular and luteal phases
- in ovaries
UTERINE
- menses, proliferative, and secretory phases
- in uterus
explain: cycle synching (not with other)
- synching lifestyle w/ phases of menstrual cycle
⤷ changing diet, exercise, self-care - helps w/ mood, energy, and productivity
- dep. on uniqueness of each female’s cycle
