The blood-brain barrier (BBB) is one of the most crucial components of the central nervous system that is fundamental to maintaining brain homeostasis. By acting as a selective, semipermeable barrier, it regulates the movement of chemicals into brain tissues, separating the extracellular fluid of the brain from blood in circulation. The blood-brain barrier (BBB) is formed by specialized endothelial cells that line the blood vessels of the brain. These cells are held together tightly by junctions that hinder free passage of molecules.

Potentially hazardous materials, including illnesses along with toxins or particular types medicines, are kept out from the brain through the blood brain barrier confirming one of its main tasks but still allowing access to essential molecules like oxygen glucose and amino acids in addition. This semi-permeable surface is important for maintaining an optimal environment for normal function of our brains. The endothelial cell membranes are supported forth by astrocytes as well as pericytes whose roles include regulating permeability and providing structural support to the blood-brain barrier (BBB).

Even though the BBB plays an important role in defense, it still makes administering drugs for neurological disorders quite difficult. A lot of medicinal substances – especially big molecules such as proteins and antibodies – cannot pass through this barrier easily due to lack of support. As a result, there has been much research aimed at overcoming this problem; for instance, by using targeted ultrasound, nanoparticles or receptor-mediated transport amongst others to facilitate better delivery of drugs into the brain.

The blood-brain barrier also serves other functions related to disease processes while at the same time protecting the organ itself thereby becoming a key factor in several neurological diseases. For example, malfunctioning BBB is observed in neurodegenerative diseases like Parkinsons’ and Alzheimers’. In these cases, the barrier may become more permeable allowing harmful substances such as immune cells or beta-amyloid peptides to get into the brain leading to faster progression of theses illnesses. Likewise incomplete blood brain barriers allow immune cells to attack myelin sheath around neurons giving rise to all classic symptoms seen in multiple sclerosis (MS).

Besides its responsibility for illness, other factors that can affect the accessibility of the blood-brain barrier include age, inflammation and trauma. This is important research for medical practitioners who want to develop new treatments to reinforce or substitute this barrier in people with neurological disorders and those suffering from brain injuries.

Therefore, blood-brain barrier plays central role to human body’s central nervous system providing essential safety but at times it raise a dilemma when administering drugs meant for treating brain associated ailments. Ongoing research quests to understand structure and composition of BBB as well as explore ways of breaching its defenses in order to treat neurological diseases.

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Known as a crucial part of the central nervous system, blood-brain barrier is a separator which filters blood from brain. The blood-brain barrier consists of unique tightly bound endothelial cells that regulate perfusion of circulatory fluids therein. It allows entrance into the brain for two essential nutrients: oxygen and glucose, while keeping out toxins, pathogens and certain drugs.

For proper neuronal function maintenance, a steady-state surrounding brain environment is necessary; this barrier is important for preserving those surroundings. With selectivity being its main feature, whereas gases together with small lipophilic molecules penetrate it easily then large hydrophilic ones do not reach the internal part of brain. There are also active transport mechanisms present in BBB that are responsible for waste elimination and brain nutrient supply.