The Bowman's capsule is a structure inside mammalian kidney where ultrafiltration takes place. The capsule is shaped like a cup, with a bundle of capillaries inside known as the glomerulus. Blood enters under high pressure through the afferent arteriole, which is is filtered through three different layers. Firstly it passes through the endothelium of the vessels in the glomerulus, then through the basement membrane and finally the cells of the Bowman's capsule. This removes most contents of blood such as water, urea, and glucose, leaving behind only large proteins and platelets which are too large to pass through the capsule. This has now separated blood into two components, filtrate which is in the Bowman’s capsule and a ‘filtered’ blood. The blood then leaves the capsule through the efferent arteriole and the filtrate passes through from the Bowman’s capsule into the proximal convoluted tubule, to allow selective reabsorption to take place .
- ↑ M. Boyle, K. Senior, Human Biology, 3rd edition, Chapter 12, Collins, 2008.