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)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe the synthetic and secretory endocrine functions of the placenta.

A
  • Hypophyseal-like hormones
    • hCG is the primary one
      • released by syncytiotrophoblasts
  • 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly