LIFESCI 2 Lecture Notes - Lecture 14: Retina Horizontal Cell, Sarcomere, Visual Cortex
Document Summary
Stimulus is converted into a change in sensory receptor"s membrane potential. Sensory receptors will either fire an ap or synapse with neurons that fire aps --> aps then transmitted to cns: chemoreceptors: universally present in animals. Respond to molecules that bind to specific protein receptors on membrane. Taste chemoreception: no aps fired, depolarization travels far enough down to receptor"s short axon to trigger nt release. Other chemoreceptions require aps firing: mechanoreceptors: 2nd general class of ancient sensory receptors. Respond to physical deformations of membrane produced by touch, stretch, pressure, motion & sound. Protein receptor could also be a sodium ion channel. Deformation of receptor membrane opens sodium channels causing a depolarization of dendrites. In mammals, mechanoreceptor = in skin, senses touch & pressure: electromagnetic receptors: respond to electrical, magnetic, & light stimuli. Most common = light-detecting photoreceptors (in the eyes) Invertebrates: light causes na+ channels to open & depolarize cell.
