Human Biology: The Three Main Functions of the Kidneys

The kidneys are a necessary part of the human body. Without them, the body would not be able to eliminate waste products. The kidneys are responsible for excreting nitrogen based wastes such are uric acids and urea. Additionally, they help maintain the proper balance of salt and water in the blood. Finally, the also help the body control the ph of its blood.

Kidneys are composed of three major parts, the renal cortex, the renal medulla, and the renal pelvis. The renal cortex is the outer layer of the kidney that contains the internals of it. The renal medulla is the part of the kidney that contains the cone shapes renal pyramids. Finally, the renal pelvis is the hollow region of the kidney that is located in the deepest part of the kidney. It is where urine is collected before it is drained into the ureter and eventually eliminated from the body. The kidneys collect urine and transport it to the urinary bladder. It is then expelled from the body by way of the urethra.

The kidney is composed of a microscopically small nephrons. A nephron is a very important part of the kidney and is divided into many specialized parts. The nephron capsule is the part of the kidney where blood is filtered. It is made from a type of cell that makes it easy for molecules to pass through it. They also have a proximal tubule, which is composed of tightly packed micovilli and mitochondria. They also attach to the collecting duct, which is used for the storage of urine, later delivering it to the renal pyramid. An exchange occurs within the nephron between it and blood to form urine.

Urine is formed in a three step process. The first step is the process of filtration. Nutrients and water are filtered out and into the body so that they can be used, while waste material remains. The next step is reabsorbing solutes that should remain in the body. Finally, the last step is secretion of the unwanted materials. This is what helps the body get rid of potentially harmful substances.

Source:

Benitz, Bill. Lecture: Human Biology. November 9, 2009