Flashcards in Lecture 12: Parturition (Kelleman) Deck (48)
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
Clicker Q: Is progesterone high or low in diestrus?
Clicker Q: Melatonin suppresses GnRH in which animal?
Clicker Q: Luteinizing hormone (LH) causes:
Neuro-endocrine loop causing oxytocin release
Main hormone for maintaining pregnancy
cervical closure fx. Maintained by which hormone?
Keeps contents from falling out and infection from getting in during preg. Progesterone
Where is progesterone produced?
CL and placenta
Which species have high progesterone throughout most of pregnancy?
ewe, sow, cow. Decreases in late-gestastion with estradiol peak
rising estradiol --> progesterone
HPA axis stands for
Activation of fetal HPA axis increases what 3 hormones
1) Corticotrpoin releasing hormone (CRH)
2) Adrenocorticotropin Hormone (ACTH)
Types of fetal stress
hypoxia, overcrowding, nutritional compromise
Fetal HPA axis:
Name the 3 organs involved
hypothalamus --> anterior pituitary --> adrenal gland (cortex)
Fetal HPA axis:
what hormone is released by the hypothalamus to stimulate the anterior pituitary?
what hormone is released by the anterior pituitary to stimulate the adrenal gland?
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
main action of progsterone
"hormone of pregnancy"
main function of estrogen
increased uterine "responsiveness"
main function of PGF2-alpha
luteolysis and contractions
main function of oxytocin
main function of relaxin
genital tract softening
Upon stimulation, what hormone can progesterone be converted to?
what hormone induces placental enzymes which convert progesterone to estradiol?
what hormone is progesterone converted to before its final conversion to estradiol?
progesterone --> testosterone --> estradiol
21 carbons --> 19 carbons --> 18 carbons
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)
- keeps fetus quiet during gestation
- during the removal of the "progesterone block" cortisol release induces progesterone to estrogen thereby decreasing progesterone and increasing estrogen.
what way can estrogen can be increased (during parturition)
enzymatic - fetal cortisol induces placental conversion of progesterone to estrogen
what are the three functions of estrogen?
1. increases uterine sensitivity to oxytocin
2. increases lubrication and sofening
3. promotes release of PGF2-alpha