The most important function of the kidneys is the homeostatic regulation of water and ion content in the blood.
This is because changes in blood volume or ionic concentrations cause serious clinical problems.
We can divide the functions of the kidneys into six general areas:
1-regulation of extracellular fluid volume and blood pressure
2-regulation of osmolality
3-maintenance of ionic balance
4-homeostatic pH regulation
5-waste excretion
6-hormone production
Kidney structure:
- cortex
- marrow
- renal artery
- renal vein
- ureter
- renal pelvis
Nephrons:
Nephrons are the functional unit of the kidneys. It is the smallest structure that can carry out all the functions of the kidneys.
Four basic processes take place in the nephrons:
1-filtration: movement of liquid from the blood into the lumen of the nephron.
2-reabsorption: movement of fluid from the lumen of the nephron into the blood
3-secretion: movement of liquid from the blood into the lumen of the nephron.
4-excretion: movement of fluid from the lumen of the nephron out of the body.