Katusemembraanid

Katusemembraanid, also known as the renal corpuscle, is a microscopic structure located at the beginning of the nephron, the functional unit of the kidney. It is responsible for the initial filtration of blood to form urine. The renal corpuscle consists of two main components: the glomerulus and the Bowman's capsule.

The glomerulus is a tuft of capillaries that filters the blood. It is surrounded by the Bowman's capsule, a cup-shaped structure that encloses the glomerulus. The Bowman's capsule is lined with a single layer of epithelial cells called podocytes, which have foot processes that wrap around the capillaries to form a filtration barrier.

The filtration process in the renal corpuscle is driven by blood pressure. As blood flows through the glomerulus, water and small molecules, such as glucose and amino acids, pass through the filtration barrier and into the Bowman's capsule, forming the initial filtrate. Larger molecules, such as proteins and blood cells, are too large to pass through the filtration barrier and remain in the bloodstream.

The filtrate then passes into the proximal convoluted tubule, where it undergoes further processing before being reabsorbed back into the bloodstream or excreted as urine. The renal corpuscle plays a crucial role in maintaining the body's fluid and electrolyte balance, as well as removing waste products from the blood.