Anatomy of the Kidney University

Anatomy of the Kidney

University of Michigan IllustrationThe function of the human kidneys (which are located in the back of the abdomen and are each close to the size of an average fist) is essentially to filter the blood by removing the waste products from the blood. Since all the blood in the human body passes through the kidneys several times each day, the function of the kidneys as a filtering agent is absolutely vital to good human health. Besides filtering the blood, the kidneys regulate the levels of water fluids. In the process of filtering the blood the kidneys actually create urine which, once filtered out of the blood, is collected in the kidney's pelvis. From there the urine drains into tubes called the ureters and into the bladder where they can be voided. As shown in the illustration, the blood flows into the kidneys through the renal artery and from there waste products and unneeded water are filtered out by the nephrons; blood that has been cleaned by the kidneys flows back into the bloodstream through the Renal vein.

Nephrons

Nephrons are microscopic filters that do the cleaning of the blood; there are about a million of nephrons and they actually produce a person's urine

Each nephron is a "long tubule, or extremely fine tube," about 30-55 mm (1.2 -- 2.2 inches) long; at one end "the tube is closed, expanded, and folded into a double-walled cuplike structure called the renal corpuscular capsule" (Encyclopedia Britannica). The illustration (of a Nephron) to the left points to: 1) Glomerulous (a cluster of microscopic capillaries; blood flows into and away from the glomerulus, part of the filtering process); 2) efferent arteriole; 3) bowman's capsule; 4) proximal convoluted tubule; (the cells that line the PCT act to absorb the materials filtered out which include glucose and electrolytes; the materials separated by the PCT are sent first