Osmoregulation
Key Stage 4
Meaning
Osmoregulation is the process of keeping the concentration of water and salts constant in an organism.
About Osmoregulation in Humans
- Osmoregulation is a type of homeostasis.
- Osmoregulation in humans is controlled by the kidneys.
- There are several ways humans can lose water so the kidneys must perform osmoregulation to ensure that too much water is not lost. The body loses water every time we exhale as some water vapour is lost from the lungs. The body also loses water when we sweat.
- Water is removed from the blood and passed into tubules in the kidneys. The water is then selectively reabsorbed into the blood depending on how much water is needed.
- Osmoregulation in the kidneys is affected by anti-diuretic hormone.
- When there is not enough water in the blood the pituitary gland secretes anti-diuretic hormone which causes the tubules to allow water back into the blood.
- When there is too much water in the blood the pituitary gland stops secreting anti-diuretic hormone which causes the tubules to stop allowing water back into the blood.
- If osmoregulation fails and the body gains too much water (overhydration) the concentration of nutrients, particularly Sodium Chloride, will become too low preventing impulses in the neurons while some cells will swell causing the brain to get larger increasing the pressure inside the skull and damaging the brain.
- If osmoregulation fails and the body loses too much water (dehydration) the concentration of nutrients and waste products becomes too high which can cause the metabolic processes in cells to slow or stop; killing the organism.