BIO230H1 Lecture Notes - Lecture 6: Photoreceptor Cell, Action Potential, Hair Cell
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BIO230H1 Full Course Notes
Verified Note
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Document Summary
Some tissues contain the same cells for organism"s entire life. Only molecular components of the cells turn over. Occurs in cells w/ very specialized architecture: auditory hair cells, photoreceptor cells. Occurs in cells exposed to harsh environments & activities: skin cells, gut cells, blood cells. Architecture allows these cells to convert sound waves into nerve impulses: physical soundwave pushes stereocilia, stereocilia tilts pulls open ion channels, change in ion concentration nerve impulse. In mammals, these cells don"t regrow when lost: permanent hearing loss! Many specific regions specialized for specific tasks- highly specialized cell structure. Demonstrates that the molecules of the cells are always being made & degraded- the cell"s components don"t change. Definition (criteria): it is not terminally differentiated, it can divide without limit, its daughter cells can remain a stem cell or differentiate. Fates of daughter cells controlled by: divisional asymmetry. Definition: one daughter cells receives factors promoting stem-ness", while other cell receives factors promoting differentiation.
