2.71

2.71 Describe ultrafiltration in the Bowman’s capsule and the composition of the glomerular filtrate

The nephrons filter blood and remove waste from the body. Waste consists of urine, which is largely water, salts and urea. At the beginning of the nephron (Bowman’s capsule), ultrafiltration begins. Blood arrives in the kidney in afferent arteriole (high pressure), which branches into blood vessels of the glomerulus. The blood vessel exiting is smaller in diameter, which means it has a high blood pressure. This forces the plasma and all the dissolved components (water, salts, amino acids, glucose and urea) into the Bowman’s capsule. The plasma is now called the glomerula filtrate. All these are filtered into the space inside of the Bowman’s capsule. Only the large plasma proteins remain in the blood and continue to the PCT.