L4: The Follicular Phase Flashcards

1
Q

follicle recruitment is stimulated by _____

A

FSH

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2
Q

what determines follicle selection

A

follicle with most FSH recceptors

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3
Q

the dominant follicle requires an ______ surge for ovulation

A

LH

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4
Q

_______ inhibits the LH surge needed for ovulation

A

progesterone
- high progesterone causes insufficient GnRH/LH levels, inhibiting ovulation

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5
Q

a dominant follicle will become atretic when _____ is high, but will ovulate if ______ decays and _______ decreases

A

progesterone high –> atretic
corpus luteum decays and progesterone decreases –> ovulation

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6
Q

after luteolysis, the negative feedback of ___________ is removed

A

progesterone on HPG axis

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7
Q

after luteolysis, positive feedback of ________ occurs

A

estrogen on HPG axis

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8
Q

formation of ovulatory follicles and estradiol secretion occurs during what phase of estrus

A

proestrus

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9
Q

phase of estrus characterized by peak estrogen secretion

A

estrus

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10
Q

phase of estrus when CL forms and begins to secrete progesterone

A

metestrus

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11
Q

phase of estrus characterized by sustained luteal secretion of preogesterone, CL functions optimally

A

diestrus

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12
Q

what is Anestrus

A

period when cyclicity stops (during pregnancy, nursing, migration, stress, malnutrition, disease)

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13
Q

how/why do high levels of progesterone inhibit ovulation

A

high progesterone causes insufficient GnRH/LH levels

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14
Q

in most animals, ovulation timing corresponds to…?

A

the events in the estrous cycle

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15
Q

what happens in proestrus

A

formation of ovulatory follicles & estradiol secretion

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16
Q

when does proestrus happen

A

begins after CL regression and ends with the onset of estrus

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17
Q

phase of estrous cycle characterized by peak estrogen secretion

A

estrus

18
Q

when does estrus occur

A

after proestrus

19
Q

what happens during metestrus

A

CL forms and begins to secrete progesterone

postovulatory phase

20
Q

what happens during diestrus

A

sustained luteal secretions of progesterone, optimal CL functioning

21
Q

average estrous cycle for a bitch

A

5.5-6.6 months

22
Q

average estrous cycle for a queen

A

18 days

23
Q

average estrous cycle for a cow

A

21 days

24
Q

physical signs of proestrus in the bitch

A
  • vulva swollen caused by increasing estrogen
  • bloody discharge from uterus
  • flirting w/ males
25
Q

what day of the estrous cycle does proestrus usually occur in the bitch

A

9 d

26
Q

what day of the estrous cycle does estrus usually occur in the bitch

A

9 d

27
Q

how long is pregnancy in a bitch

A

63 d

28
Q
A
29
Q

what day of the estrous cycle does proestrus usually occur in the queen

A

8-10 d

30
Q

signs that a queen is in proestrus

A
  • attraction to males
  • rubbing head and neck on objects
  • vocalization
  • postuing, rolling
31
Q

what day of the estrous cycle does estrus usually occur in the queen

A

9 d
ovulates 27 hours after mating

32
Q

gestation period in queens

A

60 d

33
Q

what day of the estrous cycle does proestrus usually occur in the mare

A

3 d

34
Q

what day of the estrous cycle does estrus usually occur in the mare

A

4-8 d

35
Q

signs that a mare is in estrus

A
  • tail raised
  • squats
  • frequent urination
  • exposed clitoris
  • toleration of copulation
36
Q

cows that come into estrus in the AM can be bred…

A

that same afternoon

37
Q

cows that come into estrus in the afternoon can be bred…

A

the next AM

38
Q

how does the negative feedback on the HPG axis change at puberty

A

negative feedback is reduced, resulting in more GnRH pulses of higher amplitude

GnRH pulses cause the release of LH + FSH

39
Q

3 periods during which the HPG axis is activated

A
  1. fetal development
  2. ovarian cycles during adulthood
  3. puberty
40
Q

During ________, there is a strong negative feedback on the HPG axis

A

adolescence (pre puberty)

41
Q

at puberty, the negative feedback on HPG axis is reduced, resulting in more ________pulses of a higher amplitutde

A

GnRH

42
Q

GnRH pulses cause the release of ____+_____ and stimulates the gonadal tissue to increase ______ synthesis and secretion

A

LH + FSH
steroid synthesis