Nervous System Cells and Blood-Brain Barriers

Nervous System Cells
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Nervous System Cells
Question 1.
Structure of the blood-brain barrier
The blood-brain barrier (BBB) functions as a diffusion barrier by controlling the influx of most substances or compounds from blood to the brain. BBB comprises arterial and venous vessels that vascularize the brain. It structurally comprises three cellular elements: pericytes (PCs), BBB-endothelial cells, and astrocyte end-feet. The Brain capillary endothelial cells (BECs) (BBB-endothelial cells) represent the anatomical aspect of BBB. Generally, the BBB structure comprises perivascular pericytes, astrocytes, microglial cells and neurons that form neurovascular units of BBB (Pimentel et al.,2020).
Brain capillary endothelial cells (BECs) are sealed to the tight junctions to form a cellular layer that minimizes the free transport of solutes across brain interstitial fluid (ISF) and blood. The pericytes serve as an integral part of the formation of the blood-brain barrier by encircling the endothelial cells of capillaries (Kalat, 2015). Astrocytes cells have podocytes of fibrous and protoplasmic astrocytes that encircle nerve fibres and neuronal somas and abluminal areas surrounding capillaries.
why it is important
The blood-brain barrier is critical because it protects the brain against circulating toxins and pathogens that could cause brain infections. It allows vital nutrients and oxygenation to reach the brain
How do drugs such as heroin and cocaine pass through BBB, and why does heroin have a faster effect on the brain?
The use of psychostimulants such as heroin and alcohol disrupt blood-brain barrier (BBB) integrity by causing cellular function, which leads to increased permeability (Pimentel et al.,2020). Heroin is often reversibly transformed into morphine through metabolism. Upon selective movement of heroin across the BBB, heroin is metabolized int...