The blood-brain barrier is a semipermeable membrane that separates the brain from the capillaries that pass through it. A relevant question in medical technology is the rate at which drugs are able to pass through this barrier, which subsequently informs studies in pharmacology and physiology. The Demonstration illustrates a series of structural variables applied to the cells in a simulated human brain. The comparative rates of diffusion in a variety of biologically active compounds were found by applying an integrated form of Fick's Law, given by
where is the concentration of the compound in the brain, is the concentration of the compound in the capillaries, is the diffusion coefficient, is the blood-brain barrier surface area, is the thickness and is the volume of the brain.
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