reproductive hormones & gamete development Flashcards

1
Q

hypothalamus secretes:

A

releasing hormone

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2
Q

anterior pituitary cells & what they secrete

A
  • somatotrope cells ➞ secrete growth hormone (GH)
  • corticotrope cells ➞ secrete adrenocorticotropic hormone (ACTH)
  • thyrotrope cells ➞ secrete thyroid-stimulating hormone (TSH)
  • lactotrope cells (aka manotropes) ➞ secrete prolactin (PRL)
    • key lactogenic hormone for lactation
  • gonadotrope cells ➞ secrete gonadotropins (FSH, LH)
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3
Q

posterior pituitary secretes

A

oxytocin

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4
Q

gonadotropins

A

peptide hormones that regulate testiclar & ovarian fx
* FSH (follicle stimulating hormone):
* M: stimulates sertoli cells in testes ➞ supports sperm production
* F: induces growth of follicles in ovaries
* LH (luteinizing hormone):
* M: stimulates testosterone prod by leydig cells in testes
* signals androgen production which causes 1º & 2º sex characteristics
* F: stimulates estrogen prod in ovary & ovulation
* GnRH (gonadotropin releasing hormone): released by hypothalamus that stimulates release of FSH & LH from pituitary

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5
Q

1º sex characteristics: F & M

A

F:

  • vagina
  • uterus
  • fallopian tubes (oviducts)
  • clitoris
  • cervix
  • ability to bear children

M:

  • penis
  • scrotum
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6
Q

2º sex characteristics: F & M

A

F:
* enlarged breasts
* widening of hips
* pubic hair

M:
* facial hair
* adam’s apple
* pubic hair

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7
Q

spermatogenesis

A

formation of sperm
* spermatogonium: diploid undifferentiated stem cell that becomes haploid spermatogonium
* occurs in waves ➞ continual process that ensures reproductive readiness
* occurs within seminiferous tubules
* leydig cells in intersticial tissue site of testosterone prod
* sertoli cells line edge of seminiferous tubules ➞ guard & directionality
1. diploid spermatogonium multiply by meiosis at basal lamina (outer edge of seminiferous tubule) ➞ primary spermatocyte
2. primary spermatocyte go through meiosis I ➞ secondary spermatocyte
3. secondary spermatocyte go through meiosis II ➞ spermatid = haploid daughter cell
4. spermatid goes through morphological changes ➞ spermatozoon at lumen lining

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8
Q

testosterone

A
  • growth: muscle & reprod tract
  • body composition: more muscle, less fat
  • behavior: ↑ aggression & libido
  • contributes to boar taint in pigs ➞ urine/fecal smell in non-castrated meat
    • androstenones: testicular steroid w/ pheromone fx & urine-like odor
    • skatole: product of bacteria in gut
    • androstenone prevents skatole from being broken down ➞ goes to fat & stays
    • does not happen in F ➞ no testosterone ➞ skatole can be broken down in liver & metabolized
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9
Q

oogenesis

A

production of haploid gamete (ovum/egg)

  • occurs in ovaries
  • starts when F is still fetus in mother’s womb
  • F is born with all eggs she will ever have
  • occurs at cortex
  1. oogonium undergoes mitosis: homologous chrom replicate ➞ 1º oocyte
  2. primary oocyte arrests in meiosis I before birth
    • 1º oocyte not evenly divided ➞ F must invest all resources in 1, other = polar body
    • 2º oocyte = antral/graafian follicle
  3. meosis II only proceeds after fertilization ➞ 2nd polar body
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10
Q

folliculogenesis

A
  • follicles on outer edge of ovary = cortex
  • middle of ovary = medulla ➞ blood/blood vessels
  • cyclic
    1. eggs in primordial follicle: flattened layer of cells surrounding primary oocyte
    2. primary follicle: single layer of cells surround primary oocyte
    3. secondary follicle: primary oocyte + 2 layers of cells
    4. tertiary follicle: antrum cavity forms ➞ fluid-filled cavity nourishes primary oocyte & helps with communication
    5. antrum or graafian follicle: meiosis I completes ➞ secondary oocyte (antral/graafian follicle) ruptures & releases into ovary = ovulation
    6. cells from follicle differentiate & form corpus luteum (CL) = luteinization ➞ will stay if pregnant & produce progesterone
    7. hormones signal that secondary oocyte is not fertilized ➞ CL regresses into corpus albicans
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11
Q

F reprod hormones

A

ovaries = site of oogenesis & F sex hormone production
* have multiple follicles developing simultaneously at diff stages
* estrogen made by follicle ➞ helps w/ development & fx of reprod tract & important when F is in heat/ready to breed
* progesterone: made by CL to prepare for & maintain pregnancy
* prepairs uterus for implantation
* keeps uterine envir optimal for egg
* prevents uterus from contracting & expelling egg

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12
Q
A

A: amniotic cavity
B: amnion
C: chorion
D: allantois
E: chorioallantois
F: yolk sac
blue: amniotic cavity

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13
Q
A

A: zona pellucida
B: morula
C: blastocyst
D: inner cell mass
E: blastocoele
F: trophoblast

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14
Q
A

A: luteolysis
C & F: progesterone
D: estrogen
B: follicular phase
E: ovulation
G: luteal phase

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15
Q
A

A: developing antral follicle (tertiary)
B: secondary follicle
C: primary follicle
D: primordial follicle
G & F: theca
H: ovulating follicle
I: CL
J: corpus albicans
K & L: zona pellucida
E: granulosa
M: medulla
N: cortex

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16
Q
A

A: cumulus cells
B: zona pellucida
C: follicle
D: theca
E: gransulosa cells
F: oocyte
center: antrum

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17
Q
A

A: primordial follicles
B: primary oocyte
C: follicle cells
D: primary follicle
E: zona pellucida
G: granulosa cells
H: secondary follicle
I: corpus albicans
J: antrum
K: CL
L: developing CL
M: cortex
N: graafian/antral follicle
O: coeona radiata
P: medulla

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18
Q
A

A: diestrus
B: proestrus
C: estrus
D: metestrous
E: follicular phase
F: progesterone
G: estrogen
H: LH
I: FSH

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19
Q
A

A: zona pellucida
B: pronuclei
C: polar bodies

20
Q

estrous cycle

A

amount of time it takes to produce an egg

  • polyestrous: multiple cycles throughout year
  • seasonally polyestrous: ovulate multiple times but only certain times of year
  • monoestrous: ovulate 1x/yr
  • reflex ovulator: only ovulate upon mating
  • anestrous: no ovulation or pause in ovulation (pregnancy)
21
Q

hormone cycle

A
  • ovulation ➞ CL forms ➞ makes progesterone ➞ progesterone levels rise
  • CL regresses ➞ progesterone levels drop ➞ LSH causes follicles to develop ➞ estrogen rises
  • high estrogen levels cause LH to spike (+ feedback)
    spike in LH ➞ ovulation
22
Q

ovulation hormone phases

A

luteal phase: has CL ➞ progesterone produced

  • longest
  • end of metestrus: ~4d post-estrus ➞ CL is forming
  • diestrus: CL is mature (↑progesterone levels)

follicular phase: follicles are growing & egg is maturing

  • proestrus: time btwn CL breakdown & heat
    • progesterone levels ↓
    • growth of follicle = ↑ estrogen & LH leading up to estrus
  • estrus: animal is receptive to breeding ➞ in heat
    • estrogen level peaks & right before LH surge
    • ↑ estrogen levels cause B signs
    • most animals ovulate at end of estrus (hours post-estrous) but some species ovulate during estrous ➞ important to know species
23
Q

F reproduction in birds

A
  • no preg associated w/in animal
  • external development of calcified egg
  • ~24h cycle reprod cycle
  • diff sized follicles based on stage of development
    • largest follicle = next one to ovulate
  • opening in follicle = stigma ➞ no blood vessels present
  • LH surge releases enzyme that breaks open stigma ➞ where egg ovulates
24
Q

zygote

A

sperm penetrated egg

25
Q

zona pellucida

A

glycoprotein membrane of egg ➞ attractive for sperm so they know where to go

26
Q

polar bodies

A

1/2 of oogonium that didn’t develop after meiosis I/II

27
Q

pronuclei

A

1 maternal + I paternal nuclei in zygote

28
Q

blastomere

A

indiv cell w/in developing embryo

29
Q

morula

A

compaction gives embryo an outside & inside ➞ accumulation of fluid

30
Q

blastocyst

A

key milestone structure in developing embryo ➞ cell differentiation

31
Q

blastocoel

A

fluid-filled cavity in blastocyte

32
Q

trophoblast cells

A

part of blastocyte membrane that does not form fetus ➞ forms placenta

33
Q

inner cell mass (ICM)

A

outer cells of blastocyte that form animal

34
Q

amnion

A

surrounds & cushions fetus in fluid

35
Q

yolk-sac

A

source blood cells & primordial germ cells

36
Q

chorioallantois

A

fused chorion: outer layer contributing to placenta & allantois: waste & gas exchange

37
Q

cotyledons

A

contact points on fetal chorion (placenta)

38
Q

caruncles

A

contact points on maternal uterus

39
Q

placentome

A

structure formed btwn cotyledons & caruncles

40
Q

diffuse placenta

A

many tiny contact points
* horse, pigs

41
Q

discoid placenta

A

1 site of attachment on outer edge
* primates, rodents

42
Q

cotyledonary placenta

A

medium-sized cotyledons all over
* ruminants

43
Q

zonary placenta

A

i point of contact in middle
* dog

44
Q

zonary placenta

A

i point of contact in middle
* dog

45
Q

initiating parturition

A
  • drop in progesterone
  • triggered by release of cortisol by fetus
  • results in ↑ release of estrogen by placenta
  • estrogen causes uterus (myometrium) to begin contracting
  • uterus releases prostaglandins that cause regression of CL & drop in progesterone