BIO230H1 Lecture 18: L18 Stem Cells
31 Jan 2018
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Specialized architecture of auditory hair cells in the organ of corti: before the break, we discussed how multicellular organisms develop from single cells. Stereocilia are projections on the top of the auditory hair cells. Two stereocilia are connected by a tether than connects two ion channels. Stereocilia are deflected and bent, which pulls the channels open, ions flow through, resulting in a nerve impulse sent to the brain for sound detection. In mammals, these hair cells do not re-grow when lost: their loss from disease, toxins, or extreme noise leads to permanent hearing loss, however, the molecules that make up these cells are continually made and destroyed. Stereocilia arranged on top, and tethers are visible as well. This is a specialized architecture, present for the entire life of the organism. If lost from disease or toxins, it leads to hearing loss (in humans: cells are made of many molecules, which are continually made and destroyed.
