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The nephron is the minute or microscopic structural and functional unit of the kidney. It is composed of a renal corpuscle and a renal tubule. The renal corpuscle consists of a tuft of capillaries called a glomerulus and a cup-shaped structure called Bowman's capsule. The renal tubule extends from the capsule.
This filtrate then flows along the length of the nephron, which is a tubular structure lined by a single layer of specialized cells and surrounded by capillaries. The major functions of these lining cells are the reabsorption of water and small molecules from the filtrate into the blood, and the secretion of wastes from the blood into the urine.
Diagram showing Bowman's capsule as part of the renal corpuscle. The process of filtration of the blood in the Bowman's capsule is ultrafiltration, and the normal rate of filtration is 125 ml/min, equivalent to 80 times the daily blood volume. [citation needed] It is a major site for blood filtration (including glomerulus)
This filtrate then flows along the length of the nephron, which is a tubular structure lined by a single layer of specialized cells and surrounded by capillaries. The major functions of these lining cells are the reabsorption of water and small molecules from the filtrate into the blood, and the secretion of wastes from the blood into the urine.
Mesangial cells are modified smooth muscle cells that lie between the capillaries. They regulate blood flow by their contractile activity and secrete extracellular matrix, prostaglandins, and cytokines. Mesangial cells also have phagocytic activity, removing proteins and other molecules trapped in the glomerular basement membrane or filtration ...
Blood filtration, as in other vertebrates, occurs in the renal glomeruli, where pressurized blood passes through a permeable barrier that filters out blood cells and large protein molecules, forming primary urine. The filtered primary urine is osmotically and ionically the same as blood plasma.
Filtration occurs in the glomerulus: one-fifth of the blood volume that enters the kidneys is filtered. Examples of substances reabsorbed are solute-free water, sodium, bicarbonate, glucose, and amino acids. Examples of substances secreted are hydrogen, ammonium, potassium and uric acid. The nephron is the structural and functional unit of the ...
The filtrate includes water, small molecules, and ions that easily pass through the filtration membrane. However, larger molecules such as proteins and blood cells are prevented from passing through the filtration membrane. The amount of filtrate produced every minute is called the glomerular filtration rate or GFR and amounts to 180 litres per ...