BIOLOGY 2C03 Lecture Notes - Retina, Syncytium, Glutamine
28 Jan 2013
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Document Summary
Remove ions and neurotransmitters from extracellular space. Some processes ensheath synapses and have glu transporters to remove glu from extracellular space (which is toxic to neurons) Potassium buffering hypothesis: astroctyes prevent accumulation of k in extracellular space (see physiology below) Contain glycogen granules, perhaps to provide glucose or lactate to neurons. Ca waves in astrocytes may stimulate arteriole dilation and control brain microcirculation. Respond to neuronal activity or directly influence it. Express ion channels and nxt receptors, activated upon spillout . Glu stimulates intracellular ca oscillations, propagated as waves, and may excite nearby neurons. Secrete growth factors and guide neuronal migration. True function of astrocytes hard to gauge because in situ observation is difficult. Express gfap (intermediate filament, for star-shaped structure), s100b. End feet structure at contact with capillaries. Complex morphology with highly branching processes (may result in microdomains) High k conductance (low membrane resistance and very negative resting potential)
