Barrier (medicine)
In medicine, a barrier describes a physiological barrier between a part of the body and the blood circulation in vertebrate organisms . It fulfills a protective and regulating function and prevents or at least delays the transfer of potentially harmful substances or cells from the bloodstream to the respective organ or body area. Under certain influences such as stress , but also in the event of poisoning , the permeability of the barrier can increase or decrease.
Barriers are of great importance in pharmacology. For example, the active ingredient loperamide (a diarrhea drug that is one of the opioids ) can not cross the blood-brain barrier . In contrast to z. B. to alcohol, which crosses the barrier to the brain, loperamide therefore has no intoxicating effect.
The placental barrier, which separates the bloodstream of mother and fetus, has a special function .
Examples of different barriers:
- Blood-brain barrier
- Blood-urinary barrier
- Blood-testicular barrier
- Blood-liquor barrier
- Blood-air barrier
- Blood thymus barrier
- Placental barrier
- Blood-aqueous humor barrier
- Blood-retinal barrier
- Blood-eye barrier
literature
- Peter Brenner: The structure of the blood-brain and blood-liquor barriers. Dissertation, LMU Munich, 2006