What can damage the cells of the CNS
hypoxia trauma toxins metabolic abnormalities nutritional deficiencies infections ageing genetic abnormalities
Which CNS cell is most vunerable to hypoxic damage and why
neurons neurones cannot use anaeronic glycolysis
what is an axonal reaction
a reaction within the cell body that is associated with axonal injury
`What is the response to axonal injury
increased RNA and protein syntheisi cell body swells peripheral displacement of the nucleus central chromatolysis anterograde degeneration of axon distal to injured site myelin sheeth breakdown
What happens to astrocytes when damaged
reactive response with proliferation (gliosis) leads to cell death or degeneration
What is gliosis
Gliosis is a nonspecific reactive change of glial cells in response to damage to the central nervous system (CNS). In most cases, gliosis involves the proliferation or hypertrophy of several different types of glial cells, including astrocytes, microglia, and oligodendrocytes.
why is measuring gliosis important
it is the most important histopathological indicatior of CNS injury, regardless of cause
what is hyperplasia
excessive formation of normal cells
what is hypertrophy
increase in size of tissue/organ due to increase in cell size
what is an ependymal granulation
disruption of ependymal cells can sometimes cause a local proliferation of subependymal astrocytes to produce small irregularities on the ventricular surfaces called granulations
what can cause changes to ependymal cells
infections eg viruses
how do microglia respond to injury
proliferation elongation of nuclei congregate around portions of dying neurons
How is blood supplied to the brain
via branches of the internal carotid and vertebral arteries
what is ‘special’ about the brains blood supply
it can autoregulate i.e. it can maintain its blood pressure over a wide range of systemic blood pressures
