Lecture 12: Parturition (Kelleman) Flashcards Preview

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Flashcards in Lecture 12: Parturition (Kelleman) Deck (48)
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1

Clicker Q: Which of the following are polyestrus and thus have repeated estrous cycles throughout the entire year? A's: Queens, mares, bitches, cows, or wes

Ewes

2

Clicker Q: Is progesterone high or low in diestrus?

high

3

Clicker Q: Melatonin suppresses GnRH in which animal?

Mares

4

Clicker Q: Luteinizing hormone (LH) causes:

ovulation

5

Ferguson Reflex

Neuro-endocrine loop causing oxytocin release

6

Main hormone for maintaining pregnancy

progesterone

7

cervical closure fx. Maintained by which hormone?

Keeps contents from falling out and infection from getting in during preg. Progesterone

8

Where is progesterone produced?

CL and placenta

9

Which species have high progesterone throughout most of pregnancy?

ewe, sow, cow. Decreases in late-gestastion with estradiol peak

10

rising estradiol --> progesterone

decreases

11

HPA axis stands for

hypothalamic-pituitary-adrenal axis

12

Activation of fetal HPA axis increases what 3 hormones

1) Corticotrpoin releasing hormone (CRH)
2) Adrenocorticotropin Hormone (ACTH)
3) Cortisol***

13

Types of fetal stress

hypoxia, overcrowding, nutritional compromise

14

Fetal HPA axis:
Name the 3 organs involved

hypothalamus --> anterior pituitary --> adrenal gland (cortex)

15

Fetal HPA axis:
what hormone is released by the hypothalamus to stimulate the anterior pituitary?

CRF

16

what hormone is released by the anterior pituitary to stimulate the adrenal gland?

ACTH

17

Name the 3 functions of cortisol on the fetus:

1. induce enzymatic changes in the placenta ie "communicates" with mom
2. promotes prostaglandin synthesis
3. fetal maturation

18

main action of progsterone

"pro-gestational"
"hormone of pregnancy"

19

main function of estrogen

increased uterine "responsiveness"

20

main function of PGF2-alpha

luteolysis and contractions

21

main function of oxytocin

contractions

22

main function of relaxin

genital tract softening

23

Upon stimulation, what hormone can progesterone be converted to?

estradiol

24

what hormone induces placental enzymes which convert progesterone to estradiol?

fetal cortisol

25

what hormone is progesterone converted to before its final conversion to estradiol?

testosterone

progesterone --> testosterone --> estradiol
21 carbons --> 19 carbons --> 18 carbons

26

3 ways in which progesterone falls

1: enzymatic - fetal cortisol induces placental conversion of progesterone to estrogen
2: luteolysis - via PGF2-alpha and uterine contractions
3: removal of "progesterone block" (keeps fetus quiet during gestation)

27

"progesterone block"

- keeps fetus quiet during gestation
- during the removal of the "progesterone block" cortisol release induces progesterone to estrogen thereby decreasing progesterone and increasing estrogen.

28

what way can estrogen can be increased (during parturition)

enzymatic - fetal cortisol induces placental conversion of progesterone to estrogen

29

what are the three functions of estrogen?

1. increases uterine sensitivity to oxytocin
2. increases lubrication and sofening
3. promotes release of PGF2-alpha

30

2 main functions of prostaglandin in parturition

1. causes luteolysis if CL is still present
2. will cause uterine (myometrial) contractions

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