2.71 Ultrafiltration

Nephron carries out the filtration of our blood, which will result into filtered blood and urine.

Urine is composed largely of water, salts (Sodium chloride, etc.) and urea (which contains toxic nitrogen waste of the body) which will going to emerge at the bottom of the tube to the pelvic region.

The first process starts at the bowman's capsule, and the process is called ultrafiltration - the filtration of molecules.

• Blood arrives in the kidney through the blood vessel called afferent arteriole where the blood is under high pressure.
•  Blood vessels then started to branched and became very much slower into twisted parts called glomerulus. 
• The blood then comes out through the blood vessel efferent arteriole in which the diameter of this vessel is smaller and more narrow than the afferent arteriole's. The consequence of narrowed vessels is the increase of blood pressure. 
• The high pressure forces the liquid (plasma) and plasma contains all the substance contained in blood for example water, salts, amino acids, glucose and urea. These are all forced out from the blood into the space, the inside of the bowman's capsule.
• When the plasma is forced into bowman's capsule, we call this filtrate and because it is in the glomerulus we call this glomerula filtrate.
• The blood has been filtered due to high pressure because of the smaller area of the blood vessel.