Kidneys

An essential organ involved in filtering blood, regulating blood pressure, and maintaining electrolyte balance.

The kidneys are two bean-shaped organs located in the lower back, one on each side of the spine. They play a critical role in the body's filtration system by removing waste products and excess fluids from the bloodstream to form urine. Each kidney contains approximately one million tiny filtering units called nephrons, which are responsible for this crucial function.

Terminologia Anatomica

renes

System

Urinary system

Function

The primary function of the kidneys is to filter waste products from the blood. This filtration process begins at the nephrons, where blood is processed to separate waste from essential molecules. The resulting urine contains toxins, excess salts, and water, which the body needs to eliminate. The kidneys also regulate blood pressure through the renin-angiotensin system, which adjusts the blood volume and alters vascular resistance based on the body's needs. Additionally, they help maintain the balance of electrolytes, such as sodium and potassium, ensuring that body systems function harmoniously. The kidneys also produce hormones such as erythropoietin, which stimulates the production of red blood cells in response to low oxygen levels, thus playing a vital role in maintaining overall health.

Location

The kidneys are located retroperitoneally, meaning they sit behind the peritoneum, the lining of the abdominal cavity. They are positioned on either side of the spine, extending from the level of the 12th thoracic vertebra to the 3rd lumbar vertebra. The left kidney is typically situated slightly higher than the right kidney due to the presence of the liver on the right side. Each kidney is protected by a capsule of fibrous tissue and surrounded by layers of fat, providing cushioning and support.

Did You Know?

The kidneys can filter about 45 gallons (170 liters) of blood each day.
Each kidney has its own distinct blood supply, receiving blood from the renal arteries.
People can live with just one kidney, and the remaining kidney can increase its capacity to filter waste.
Kidneys can regenerate and recover from damage, showing remarkable resilience in some cases.