BBB

The BBB refers to the blood-brain barrier which is a network of blood vessels and tissue made up of tightly packed cells that line the small blood vessels of the brain and spinal cord and form a “wall” that helps keep harmful substances from reaching the brain. The BBB lets some substances, such as water, oxygen, and general anesthetics, pass into the brain. It also keeps out bacteria, viruses, and toxins, but also prevents most breast cancer treatments (and other drugs) from penetrating into the brain.