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)
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Fetal HPA axis:
what hormone is released by the hypothalamus to stimulate the anterior pituitary?
CRF
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what hormone is released by the anterior pituitary to stimulate the adrenal gland?
ACTH
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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
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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
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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)
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"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.
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what way can estrogen can be increased (during parturition)
enzymatic - fetal cortisol induces placental conversion of progesterone to estrogen
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what are the three functions of estrogen?
1. increases uterine sensitivity to oxytocin
2. increases lubrication and sofening
3. promotes release of PGF2-alpha
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