Question

. How is the blood-brain barrier created and maintained? List 3 regions in the brain where the blood-brain barrier is absent. Please answer this question in one paragraph in great detail

Answer 1

Blood brain barrier is the biological barrier that surrounds the brain. It acts as a barrier between the extracellular fluid in brain and the blood outside the brain. It is selectively permeable to substances present in the blods surrounding the brain. This helps prevent entry of harmful substances, pathogens and free radicals to enter in the brain and damage it.
The blood brain barrier is formed by three componenets :

1. Endothelial cells of the brain capillaries and the tight junctions between these cells.
2. Astrocyte feet that projects from the astrocyte and encircled the capillaries. They provide mechanical support tp the blood brain barrier.
3. Pericytes.
The circumventricular organs in the brain present around third and fourth ventricle lack blood brain barrier. These are pineal gland, putuitary neural lobe and hypothalamus region.