The importance of kidneys
The kidney factory is a typical model factory, open all year round. Work 24 hours a day, seven days a week. With every beat of the heart, as much as 20% to 25% of the blood flows through the kidneys. filters 1 liter every minute. In just one hour, it can filter the blood in the whole body 12 times.
In a day, the total blood volume filtered by the kidneys reaches 180 liters, and 1% of urine is filtered out of the body. The efficiency of the kidneys is so high that it far exceeds any water purifier made by humans. How does this highly efficient blood purification factory work?
Blood enters the nephron along the afferent arteriole, and the first place it reaches is the glomerulus. The glomerulus is composed of dozens of winding capillaries, and the blood vessel walls form a three-layer membrane structure from the inside to the outside. The membrane structure blocks blood cells, filters out water, salt and metabolic waste, and finally forms ultrafiltrate - original urine - in the renal capsule.
Following the original urine, we come to the renal tubule. It is surrounded by abundant peritubular capillaries, and when the original urine flows through, almost all nutrients are completely reabsorbed.
The last small amount of liquid left is rich in metabolic waste, which is our urine.
5
