Lecture 14: Placental Physiology Flashcards
What are characteristics of the early placenta?
Thick, low permeability, small surface area, diffusion conduction is miniscule
What are the 3 major functions of the placenta?
Diffusion of O2 and CO2, diffusion of foodstuffs, excretion of waste
What are characteristics of the late placenta?
Thin, high permeability, large surface area, large placental diffusion
What is the PO2 of the mother late in pregnancy?
5o mmHg
What is the PO2 of the fetus late in pregnancy?
30 mmHg
What does the Bohr effect say?
Hemoglobin can carry more oxygen at a low PCO2
What sort of diffusion does foodstuffs use to cross the placenta?
Facilitated diffusion of glucose via trophoblast cells
What waste products diffuse from fetus to maternal blood?
Urea, uric acid, & creatinine
What does HCG secretion do?
1) Prevents involution and increases growth of corpus luteum
2) CL increase secretion of progesterone & estrogen
3) Interstitial cell-stimulating effect on testes
4) Production of testosterone until birth
Toward the end of pregnancy, _____ secretion levels are 30X higher than normal levels for the mother.
Estrogen
What does estrogen secretion do?
Causes enlargement of maternal parts: uterus, breasts, genitalia, etc.
Progesterone is secreted in _____ quantities by corpus luteum early and _____ quantities by the placenta
Small.
Large
What does progesterone secretion do?
1) Causes development of decidual cells
2) Decreases contractility of uterus
3) Increases fallopian tube and uterus secretions
What is HCS secreted by and when is it secreted?
Placenta beginning in 5th week
What does HCS secretion do?
1) Decreased insulin sensitivity & decreased use of glucose by mother
2) General metabolic hormone
