What type of cells make up the blood-brain barrier?

The blood-brain barrier is primarily composed of specialized endothelial cells that line the blood vessels in the brain. These endothelial cells are tightly packed together, forming tight junctions that restrict the passage of substances from the bloodstream into the brain, thus protecting the neural tissue from potentially harmful substances. Additionally, astrocytes, a type of glial cell, play a critical supportive role by enveloping the blood vessels and regulating the transport of molecules, as well as maintaining the overall environment of the neurons.

This combination of astrocytes and endothelial cells is essential for the integrity and function of the blood-brain barrier. The presence of these specific cell types ensures that essential nutrients can pass through while keeping toxins and pathogens at bay, maintaining the delicate homeostasis required for optimal brain function. Other cell types such as neurons and oligodendrocytes are involved in different functions within the central nervous system but do not directly comprise the blood-brain barrier.