The human kidney is a both a complex and very important organ!
kidneys are bean-shaped organs, each about the size of a fist. The kidneys are located just below the rib cage, either side of the spine. Between them, each day the two kidneys filter about 140 to 170 liters of blood to produce about 1 to 2 liters of urine. This filtering process involved lots of specialized proteins in the cell membranes of the kidney’s Nephrons. Nephrons are the basic structural and functional unit of the kidney. Their main function is to regulate the concentration of water and soluble substances like salts by filtering the blood, reabsorbing what is needed and excreting the rest as urine.
The urine then flows from the kidneys to the bladder via two thin tubes of muscle called ureters, one on each side of the bladder. The bladder stores the urine. While the bladder fills with urine the muscles of the bladder wall remain relaxed. As the bladder fills to it’s maximum capacity, signals sent to the brain tell a person to find a toilet soon. When the bladder empties, urine flows out of the body through a tube called the urethra, located at the bottom of the bladder.
Like all organs in the body, the kidneys perform a specific and quite amazing job. If you have ever seen the size of a hospital dialysis machine that is used to perform the job of kidneys when they do not function properly, just think that nature has managed to put all that into those two small organs at the base of your back.
The most important structure in the kidney is the nephron and it is a filtration device. Each kidney contains hundreds of thousands of nephrons.
Processes in our body produce waste such as salt, urea and other chemicals. The blood passes by these filters and small molecules like salt and urea can pass through and are removed, together with the water we don’t need, and this ends up as urine in the bladder. Large molecules like proteins, and bigger objects like blood cells, can’t pass through the filter.
Working well your kidneys can process about 150 litres of blood in a day, just to extract a couple of litres of urine.