PSYC 2P35 Lecture Notes - Lecture 3: Meninges, Extracellular Fluid, Glycogen
23 Jan 2018
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The brain floats in its skull mostly unattached, buoyed by cerebrospinal fluid, a colorless liquid that cushions the brain and spine. If shaken hard enough, and especially if the brain twists, parts of neurons can stretch and even shear. The twisting motion tears open axons, the long, slim fibers that connect one neuron to another neuron (or to a muscle or organ). With the axon"s outer protective sheath ripped open, the thin filaments inside start to unravel. These filaments, called microtubules, allow cargo to travel from the nucleus to target cells. When the microtubules are damaged, molecules of glutamate leak from the cell. The cell also releases several proteins: tau (a structural element that helps to hold together microtubules), amyloid precursor protein and tdp-43. The dispersal of these molecules signals nearby cells that damage has occurred, triggering an immune and inflammatory response.
