BLOOD-BRAIN BARRIER: HISTOLOGICAL STRUCTURE AND FUNCTION
Keywords:
Blood-brain barrier (BBB), neurovascular unit, capillary endothelium, tight junctions, pericytes, astrocytes, CNS homeostasis, selective permeability.Abstract
The blood-brain barrier (BBB) is a specialized physiological barrier that protects the central nervous system from harmful substances circulating in the blood while maintaining a stable environment for neuronal function. Histologically, it is formed by endothelial cells of cerebral capillaries connected by tight junctions, basement membrane, pericytes, and astrocyte end-feet. The BBB regulates the transport of nutrients, ions, and metabolic products between the blood and brain tissue. Its integrity is essential for normal brain homeostasis, and disruption of the BBB is associated with neurological diseases such as stroke, meningitis, multiple sclerosis, and Alzheimer’s disease. The blood-brain barrier is an important anatomical and functional system that separates the blood circulation from the brain extracellular fluid. Its unique histological organization ensures selective permeability and protects nervous tissue from harmful agents. The barrier is primarily formed by specialized endothelial cells connected by tight junctions and supported by astrocytes and pericytes. The BBB participates in metabolic regulation, immune protection, and maintenance of brain homeostasis. Understanding the structure and functions of the blood-brain barrier is essential for studying the pathogenesis of various diseases and developing effective therapeutic approaches for disorders of the central nervous system.
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