L4: The Follicular Phase

Question 1

follicle recruitment is stimulated by _____

Answer 1

FSH

Question 2

what determines follicle selection

Answer 2

follicle with most FSH recceptors

Question 3

the dominant follicle requires an ______ surge for ovulation

Answer 3

LH

Question 4

_______ inhibits the LH surge needed for ovulation

Answer 4

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

Question 5

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

Answer 5

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

Question 6

after luteolysis, the negative feedback of ___________ is removed

Answer 6

progesterone on HPG axis

Question 7

after luteolysis, positive feedback of ________ occurs

Answer 7

estrogen on HPG axis

Question 8

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

Answer 8

proestrus

Question 9

phase of estrus characterized by peak estrogen secretion

Answer 9

estrus

Question 10

phase of estrus when CL forms and begins to secrete progesterone

Answer 10

metestrus

Question 11

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

Answer 11

diestrus

Question 12

what is Anestrus

Answer 12

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

Question 13

how/why do high levels of progesterone inhibit ovulation

Answer 13

high progesterone causes insufficient GnRH/LH levels

Question 14

in most animals, ovulation timing corresponds to…?

Answer 14

the events in the estrous cycle

Question 15

what happens in proestrus

Answer 15

formation of ovulatory follicles & estradiol secretion

Question 16

when does proestrus happen

Answer 16

begins after CL regression and ends with the onset of estrus

Question 17

phase of estrous cycle characterized by peak estrogen secretion

Answer 17

estrus

Question 18

when does estrus occur

Answer 18

after proestrus

Question 19

what happens during metestrus

Answer 19

CL forms and begins to secrete progesterone

postovulatory phase

Question 20

what happens during diestrus

Answer 20

sustained luteal secretions of progesterone, optimal CL functioning

Question 21

average estrous cycle for a bitch

Answer 21

5.5-6.6 months

Question 22

average estrous cycle for a queen

Answer 22

18 days

Question 23

average estrous cycle for a cow

Answer 23

21 days

Question 24

physical signs of proestrus in the bitch

Answer 24

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

Question 25

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

Answer 25

9 d

Question 26

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

Answer 26

9 d

Question 27

how long is pregnancy in a bitch

Answer 27

63 d

Question 29

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

Answer 29

8-10 d

Question 30

signs that a queen is in proestrus

Answer 30

* attraction to males * rubbing head and neck on objects * vocalization * postuing, rolling

Question 31

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

Answer 31

9 d ovulates 27 hours after mating

Question 32

gestation period in queens

Answer 32

60 d

Question 33

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

Answer 33

3 d

Question 34

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

Answer 34

4-8 d

Question 35

signs that a mare is in estrus

Answer 35

* tail raised * squats * frequent urination * exposed clitoris * toleration of copulation

Question 36

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

Answer 36

that same afternoon

Question 37

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

Answer 37

the next AM

Question 38

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

Answer 38

negative feedback is reduced, resulting in more GnRH pulses of higher amplitude GnRH pulses cause the release of LH + FSH

Question 39

3 periods during which the HPG axis is activated

Answer 39

1. fetal development 2. ovarian cycles during adulthood 3. puberty

Question 40

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

Answer 40

adolescence (pre puberty)

Question 41

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

Answer 41

GnRH

Question 42

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

Answer 42

LH + FSH steroid synthesis