Placenta, umbilical cord and amnion

HideShow resource information
View mindmap
  • Placenta, umbilical cord and amnion
    • Placenta
      • begins to develop at implantation and after approximately 12 weeks, it is a thick, disc-like structure with finger-like projections called villi that extend deep into the wall of the uterus.
      • site of exchange by the process of diffusion
      • provides important adaptions for diffusion:
        • the rich blood system of the mother runs in a counter-current system to that of the foetus so there will always be a concentration gradient which allows diffusion into the foetal blood
        • the blood systems of the mother and foetus are close together, separated by a thin membrane but not joined, reducing the length of the pathway for diffusion
        • the villi provide a large surface area for exchange of dissolved nutrients, oxygen, carbon dioxide and urea
      • amnion contains amniotic fluid
      • umbilical cord:
        • umbilical artery: carries urea, carbon dioxide and other wastes back to the mother
        • umbilical vein: carries oxygen, glucose, amino acids and other nutrients from the mother to the foetus
    • exchange of materials by diffusion only takes place in the placenta
    • the role of the umbilical cord is the transport these materials to or from the foetus in the blood vessels of the umbilical artery and the umbilical vein
    • the amnion contains amniotic fluid which cushions the foetus, supporting it during development and protecting it against mechanical shock and temperature fluctuations


No comments have yet been made

Similar Fun resources:

See all Fun resources »See all Fun resources »