The placenta Flashcards
What nutrients does the foetus get from the mother through the placenta?
glucose, amino acids, water, fats, oxygen
How are waste products removed from the foetus’s blood?
Carbon dioxide, urea and others diffuse into the mothers blood in the placenta. This prevents them from rising to dangerous levels
How do bloods in the placenta travel?
The bloods in the placenta run in opposite directions to each other, never mixing.
How do substances in the placenta move and why?
They move through diffusion because of the difference in concentration gradients.
How does the placenta act as a barrier?
It prevents harmful toxins and pathogens from diffusing into the foetus’s blood
What substances can still diffuse through the placenta and into the baby?
nicotine, alcohol and the rubella virus (they are all very small)
What are pregnant mothers advised not to do?
smoke, drink alcohol or expose themselves to the rubella virus (and other viruses)
How is the placenta adapted for its function?
It has a large surface area and a thin wall for efficient diffusion
What is the function of the umbilical cord?
Connects the foetus’s blood supply to the placenta
Why doesn’t it hurt when the umbilical cord is cut after a baby is born?
No nerves in the umbilical cord, just two blood vessels
How is afterbirth produced?
The placenta detatches from the uterus after birth and is pushed out due to contractions in the muscular wall of the uterus.
