Explain the terms resorption and secretion in reference to the nephron.

The nephron is the basic functional unit of the kidney responsible for urine formation. Urine is formed from the filtration of blood that passes inside the nephrons. Briefly, we can say that the process of urine formation occurs in three stages: filtration, resorption and secretion.

Explanation:

Initially arterial blood arrives under high pressure in the glomerulus capillaries. At this point, the pressure causes some of the plasma to flow out into Bowman's capsule. This plasma passage is known as filtration. The filtrate formed is very similar to plasma inside the blood vessels, however it has no proteins or blood cells.

The material from the filtration proceeds to the renal tubules, where resorption occurs. At this stage, important substances that should not be missed are reabsorbed. Almost 99% of the filtered water in the corpuscle, for example, is absorbed. Major resorption is also found for glucose and amino acids.

In the proximal tubule most of the reabsorption of water and sodium occurs, two substances essential for the functioning of the body. It is estimated that about 67% to 80% Na + ions and water are absorbed from the filtrate at this stage. In Henle's loop and distal tubule, substances are also reabsorbed.

In addition to resorption, secretion occurs in the renal tubule, which is a process opposite to resorption. In secretion, the substances present in the capillaries are released into the renal tubule, which ensures their elimination through the urine. Toxic metabolism substances and drugs, for example, are excreted in the proximal tubule.

At the end of these three steps we have urine formed. Thus, we can say that the urine is the product formed by the glomerular filtrate, removing what was reabsorbed and adding what was secreted.