Resorption

The term absorption (Latin resorbere = " absorb "; PPP: resorptum → resorptio = " wicking " ) refers to the uptake in biological systems. In humans and vertebrates thus the absorption of substances from the digested food in the gut is especially meant during digestion (eg, cleavage products of food constituents such as carbohydrates, proteins and fats, vitamins, minerals, water, drugs, toxins, and others).

In humans, absorption through epithelial cells, especially in the small intestine is of great importance. For some substances (eg, ointments, contact poisons ), absorption can also take place through the skin.

Expiration

A distinction is made between passive and active absorption in the small intestine. In the passive absorption of nutrients and other components absorbable substances by osmosis from places of high concentration to reach such a low concentration. This happens for example in the small intestine, where, the interior (lumen) a high concentration of nutrients, the cells of the intestinal mucosa ( mucosal ) have a lower concentration. Without or against a concentration gradient, the recording can be done by active resorption. The substances to be transported with the help of transporter molecules (so-called " Carrier Proteins " ) and under consumption or splitting of the energy carrier adenosine triphosphate ( ATP ) can be absorbed against the concentration gradient.

Generally, the nutrient components, such as glucose and amino acids, first of all in the cells of the intestinal wall ( mucosal cells ) can be absorbed and from there into the blood that enters the portal vein to the liver, transported to the digestion. Non-polar substances such as fats continue to be absorbed by the absorption into the mucosal cells in the lymph.

In the tubules - (see nephron ) - the kidney takes place after filtration in the glomeruli and formation of the primary urine, a reabsorption of water, glucose and other substances necessary for life ( reabsorption ) from the primary urine back into the blood instead. Here, for example, glucose is actively reabsorbed from the primary urine into the blood.

Definitions

In the English or international usage, only the terms absorption and reabsorption of the operations described above are used. This has also established itself in the German language, in part, because by the prefix it re- occurs in the word reabsorption to both inelegant and misleading word formation. That's why today many physiologists advocate for the systematic introduction of the English term pair in the German language area. For example, materials would be absorbed from the intestinal lumen and reabsorbed from the renal tubules into the blood.