pregnancy

• placenta

  • foetus gains nutrients and antibodies from mom's blood
  • placenta&uterus have many blood vessels that run close to e/o, but don't touch / join bc mom's blood pressure too high for foetal blood vessels &wld damage them + prevent pathogens & harmful chemicals (nicotine can pass thru)
  • foetus blood connects to n from placenta by umbilical cord
  • mom's blood absorbs waste products from foetus blood in placenta so they don't build up to dangerous levels
  • the movement of most molecules across the placenta occurs by diffusion and sometimes active transport (large SA and thin walls)
• label

  A) placenta

  B) villi

  C) placental membrane

  D) placenta

  E) umbilical cord

  F) foetus

  G) intervillous

  H) mother's

  
• birth

  • After the baby has been born, the umbilical cord is cut
  • This does not hurt as there are no nerves in it, just two blood vessels
  • It is tied off to prevent bleeding and shrivels up and falls off after a few days leaving the belly button behind
  • The placenta detaches from the uterus wall shortly after birth and is pushed out due to contractions in the muscular wall of the uterus. This is known as the afterbirth