Final answer:
The blood-brain barrier includes astrocyte foot processes, capillary endothelial cells, pericytes, tight junctions, and the basement membrane. These components work cooperatively to maintain a highly selective barrier that allows essential nutrients to reach the CNS while blocking potentially harmful substances.
Step-by-step explanation:
The blood-brain barrier (BBB) consists of several components that work together to protect the central nervous system (CNS) from potentially harmful substances in the blood while allowing essential nutrients to pass through. Besides astrocyte foot processes, other integral components of the blood-brain barrier include: capillary endothelial cells with tight junctions that limit the permeability of the capillary walls, pericytes which are involved in the regulation of blood flow and structural integrity of the capillaries, tight junctions that prevent the diffusion of substances between the endothelial cells, and the basement membrane that provides support and regulates molecular traffic. Together, these structures create a selectively permeable barrier that permits only certain substances to enter the brain from the bloodstream while blocking others.