neuroglia that support neurons and blood vessels are
Neuroglia Microglia are specialized macrophages capable of phagocytosis that protect neurons of the central nervous system.[17] They are derived from the earliest wave of mononuclear cells that originate in yolk sac blood islands early in development, and colonize the brain shortly after the neural precursors begin to differentiate.[18]
Blood–brain barrier The blood–brain barrier (BBB) is a highly selective semipermeable border that separates the circulating blood from the brain and extracellular fluid in the central nervous system (CNS).[1] The blood–brain barrier is formed by endothelial cells of the capillary wall, astrocyte end-feet ensheathing the capillary, and pericytes embedded in the capillary basement membrane.[2] This system allows the passage of water, some gases, and lipid-soluble molecules by passive diffusion, as well as the selective transport of molecules such as glucose and amino acids that are crucial to neural function. Specialized structures participating in sensory and secretory integration within neuronal networks – the circumventricular organs and choroid plexus – do not have a blood–brain barrier.