Nephron
The kidneys in our body extract urine (waste) from the blood.
The kidneys are fist-sized and are located on the left and right behind the waist.
The blood vessel that enters the kidney is the renal artery, and the blood vessel that exits is the renal vein. In addition, there is a urinary duct that collects and drains urine. The outer part of the kidney comprises tissue called the nephron. The part connected to the renal artery is called the glomerulus, and it acts like a sieve that filters out waste products, etc. The glomerulus is a microscopic and delicate tissue. Large clumps of red blood cells, white blood cells, and proteins cannot pass through the glomerulus. Small waste products 'filtered' in the glomerulus move to Bowman's capsule and meet the capillaries through the renal tubule.
In capillaries, ‘reabsorption’ and ‘secretion’ occur. Waste products that have not yet been discarded are ‘secreted’ into the renal tubules, and glucose and amino acids that must not be discarded are ‘reabsorbed’ back into the capillaries.