Implantation 1 Flashcards
List the functions of the placenta.
1
Q
List the functions of the placenta.
A
- Interface between maternal circulation and fetal circulation
- Gas exchange
- Excretory functions, water balance, pH regulation
- Catabolic and resorptive functions, nutrition
- Synthetic and secretory endocrine functions
- Metabolic functions, conjugating waste
- Hematopoiesis in early pregnancy
- Temperature regulation, partially
- Immunologic functions (tolerance of pregnancy - fetal antigens need to be ignored by the maternal immune system)
3
Q
Describe the process of excretory functions, water balance, and pH regulation of the placenta.
A
- Water transfer across placenta
- depends on hydrostatic and osmotic pressure
- most movement is passive, but there may be a trophoblast water channel (aquaporins)
- Sodium and chloride levels in fetus and mother are similar
- Potassium, calcium, and phosphate are higher in the fetus
- enter by active transport
5
Q
Describe the role of the placenta in catabolic and resoprtive functions as well as nutrition.
A
- Glucose transported via GLUT-1 transporter and other GLUT transporters (facilitated diffusion)
- Amino acid metabolism and transport is complex
- Lipid metabolism and transport primarily through diffusion mediated by material surface with lipoprotein lipase
- generates free fatty acids and glycerol
7
Q
Describe the synthetic and secretory endocrine functions of the placenta.
A
-
Hypophyseal-like hormones
- hCG is the primary one
- released by syncytiotrophoblasts
- hCG is the primary one
-
Steroidogenic hormones
- derived from metabolism of maternal cholesterol
- progesterone (syncytio- and cytotrophoblasts)
- estrogen
- from androgens secreted by fetal adrenal gland
- much of it is conjugated
- Placental peptides similar to hypothalamic factors
- Chorionic cytokines, growth factors, and peptides
- Eicosanoids and prostanoids
9
Q
What are the mteabolic functions of the placenta as well as its role in conjugating waste?
A
- Syncytiotrophoblast has many export pumps (ex. multidrug resistance protein 1, MDR1)
- Placenta has numerous cytochrome P450 enzymes that metabolize xenobiotics
- Most proteins do not corss the placenta
- some are transported by pinocytosis
- maternal IgG antibodies provide the fetus with passive immunity