Image SS21245872 (Blood-Brain Barrier, illustration)Medical illustration of the hematoencephalic bar

Image SS21245872 (Blood-Brain Barrier, illustration)

Medical illustration of the hematoencephalic barrier between the blood flow and the central nervous system. This is called the Blood-Brain Barrier.

This system regulates the environment (homeostasis) in the brain by separating it from the blood. Both the endothelial cells (red) that line the capillaries and the surrounding astrocytes (pink) are essential components of this barrier.

Learn More About The Blood-Brain Barrier 

The blood-brain barrier stops harmful chemicals and bacteria from reaching the brain. The blue cells pictured are the neurons in the brain. 

Viruses and special types of drugs are able to pass the blood-brain barrier.

© Gunilla Elam / Science Source