- Biology- Kidneys
- Main roles; Removal of Urea from the blood, Adjust ion levels, Adjust water content and reabsorb useful items.
- Ultra filtration; A high pressure is built up which squeezes water, urea, ions and glucose out of the blood and into the bowmans capsule. The glomerulus and the Bowmans capsule act as filters, so big mocules (blood cells, protein) are not squeezed out.
- Reabsorption; all of the glucose is selectively reabsorbed against the concentration gradient. some water and ions are reabsorbed too.
- Release of wastes; Urea and excess water carry on down the nephron, into the ureter and down to the bladder. Urine is excreted through the urethra.
- Excess water- Filted by ultrafiltration and is excreted in the Urea. This is called osmoregulation
- Glucose- Gets selectively reabsorbed into the blood
- Urea - Gets filtered by ultrafiltration, passes out of the urethra.
- Some Ions (such as sodium) gets selectively reabsorbed, others are filtered out.