THE FUNCTIONS OF THE EXCRETORY SYSTEM
- A renal artery leads to each kidney and transportsthe blood loaded with waste. A renal vein leaves each kidney carrying clean blood. The kidneys purify the blood via urines
- Urine formation.
- Stage one: filtartion; A first filtration takes place in the glomerulus, producing what we call primary urine, which contains water, toxic substances, mineral salts and useful substances (glucose and amino acids)
- Stage two: reabsorption; A large part of the substances in primary urine is reabsorbed in the renal tubule and returned to the blood. The result is the definitive urine that empties into the collecting duct and is expelled through the urinary tract
As well as purifying the blood, the formation of urine regulates the quantity of water and minerals in the body, thereby helping to maintain its internal balance