Answer: The renal filtration structure that restricts the movement of blood, cells, and large molecules is called the glomerular filtration barrier.
Step-by-step explanation:
1) Renal filtration: Renal filtration is the process by which the kidneys filter blood to remove waste products and excess substances from the body. This filtration occurs in the nephrons, which are the functional units of the kidneys.
2) Glomerular filtration barrier: The glomerular filtration barrier is a specialized structure located in the glomerulus, which is a network of capillaries in the nephron. This barrier consists of three layers: the fenestrated endothelium, the basement membrane, and the podocytes.
3) Fenestrated endothelium: The first layer of the glomerular filtration barrier is composed of endothelial cells that have small pores or fenestrations. These fenestrations allow small molecules and ions to pass through, but they restrict the movement of blood cells and larger molecules such as proteins.
4) Basement membrane: The second layer of the glomerular filtration barrier is the basement membrane, which is a dense, negatively charged meshwork of proteins. This membrane further restricts the passage of larger molecules, especially negatively charged ones, such as albumin.
5) Podocytes: The final layer of the glomerular filtration barrier is formed by specialized cells called podocytes. Podocytes have foot-like extensions called pedicels that wrap around the capillaries in the glomerulus. The pedicels have small filtration slits between them, which act as additional barriers to prevent the passage of large molecules.
In summary, the glomerular filtration barrier in the kidneys restricts the movement of blood, cells, and large molecules. It consists of the fenestrated endothelium, basement membrane, and podocytes, working together to selectively filter the blood and allow the passage of smaller substances while preventing the loss of blood cells and larger molecules.