Kidney is very important organ for animals because it sends wastes in our body out through some processes. Kidney is an organ that filters and send wastes that is forming of urine out. Generally, humans have 2 kidneys. And length of humans is 10cm, width is 5cm and thickness is 3cm. Its shape is similar to kidney bean. Kidneys are located under diaphragm and its weigh is total 200g. Statistically, leftside kidney is bigger than rightside kidney.
external image KidneyAnatomy.jpg
This diagram shows structure of kidneys in detail.

Process of creating urine
Water, amino acid, glucose, urea and other substances move from glomerulus to bowman's capsule. They are filtered and make a liquid thing and then this liquid is absorbed and secreted in renal tubule. After that, wastes in blood and mineral are concentrated as ingredient of urine in collecting tubule. Urine passes through collecting tubule, renal pelvis, ureter and bladder. And then it comes out from humans' body through urethra.

Functions of kidney
As sending urine out, kidney does some functions. One of them is that kidney removes no neccessary materials in blood. And it also removes excess material in blood. If concentration material in blood is low, it would be not removed. However, concentration is high, it would be removed. For example, blood sugar that is lower than 0.17% would not be removed but blood sugar that is higher than 0.17%, it would be removed. Next thing is that kidney controls osmotic pressure. When water in blood increases and osmotic pressure decreases, kidney removes water in blood. Next, kidney controls pH that is a measure of the acidity or bascirt of a solution.

There are some diseases that occurs in kidney. There are Nephrotic syndrome, kidney cancer, chronic renal failure, Reye's syndrome, gout, candidiasis, behcets disease and other diseases.

- (Accessed 14/04/09) "ABOUT KIDNEY"

- (Accessed 14/04/09) "Diagram of kidney"