What is the blood-brain barrier?

The blood-brain barrier is best described as a protective feature of the capillary walls of the brain. It consists of tightly packed endothelial cells that line the blood vessels in the brain, creating a selective permeability barrier. This barrier is crucial for preventing potentially harmful substances in the bloodstream from entering the brain while allowing essential nutrients, oxygen, and other necessary molecules to pass through.

This selective barrier helps to maintain the brain's stable environment, which is vital for proper neuronal function and overall brain health. It plays a significant role in protecting the brain from pathogens, toxins, and fluctuations in blood chemistry, which could disrupt neuronal activity. Understanding the function of the blood-brain barrier is essential for medical professionals, especially in fields related to neurology and pharmacology, as it has implications for drug delivery and treatment of neurological disorders.