The Human Kidneys

The kidney are a pair of red-brown, bean-shaped organs. Each kidney is about the size of a first. The kidneys are covered and protected by thick layers of fats. A longitudinal section of the kidney shows that it is divide into two regions. The dark red outer region is called the cortex and the pale-red inner region is called the medulla. The medulla is filled with cone-shaped tissues called pyramids. The apices of the pyramids open into a funnel shapes cavity called the pelvis. The pelvis drains urine into the ureter.Each human kidney has at least one million tiny blood filters. Urine is formed within these tiny blood filters.

 

Functions of the kidneys

1. The kidneys remove nitrogenous waste products such as urea along with excess water and mineral salts in the form of urine
2. Kidneys keep the water and mineral contents in our body in balance
3. The kidneys control the amount of mineral salts in the body fluid
4. The kidneys also help to maintain the pH of blood and tissue fluid.

The Human Urinary System

The urinary system consists of a pair of kidneys, a pair of ureters, the urinary bladder and the urethra. Blood is carried to each kidney by the renal artery and away from it by the renal vein. The kidneys are located on either side of the spine at the back of the abdominal cavity. They lie just above the waistline and the left kidney is slightly higher than the right kidney.

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The blood is filtered within the kidney. Waste products (urea) and excess substances (mineral salts and water) are converted into urine. The ureter carry the urine from the kidneys to the urinary bladder. The urinary bladder store urine and gradually expands like a balloon. When the muscles in the wall of the bladder contract, urine is expelled to the exterior via the urethra. This process is called urination.