How does blood enter and leave the kidney?

Blood enters the kidney through the renal artery and leaves the kidney through the renal vein.

The kidneys are vital organs in the human body, responsible for filtering waste products, excess water, and other impurities from the blood. These waste products are stored in the bladder and later removed during urination. The process of blood entering and leaving the kidney is a crucial part of this filtration process.

Blood enters the kidney via the renal artery. The renal artery branches off from the aorta, the main blood vessel that carries oxygenated blood from the heart to the rest of the body. The renal artery is responsible for delivering a high volume of blood to the kidney, approximately 20% of the total cardiac output. This blood is rich in oxygen and nutrients, which are necessary for the kidney to perform its functions.

Once the blood enters the kidney, it is distributed to millions of tiny filtering units known as nephrons. Each nephron consists of a glomerulus and a tubule. The glomerulus is a tiny blood vessel, or capillary, that performs the first step of filtering blood. The filtered blood then moves into the tubule, where various substances are either added or removed according to the body's needs. This process results in the formation of urine, which contains waste products and unneeded substances.

The cleaned blood, now free of waste and excess substances, leaves the kidney through the renal vein. The renal vein carries the filtered blood back to the heart, where it is then circulated throughout the rest of the body. This process of blood entering and leaving the kidney is continuous and vital for maintaining the body's overall health and homeostasis.

In summary, the renal artery and renal vein play crucial roles in the kidney's function of filtering blood. The renal artery brings oxygen-rich blood into the kidney, where it is filtered by nephrons. The renal vein then carries the cleaned blood away from the kidney and back to the heart.