BIOL 306 Lecture Notes - Lecture 9: Olfactory System, Biochemical Cascade, Retina
15 Jan 2018
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Document Summary
Transduction: conversion of stimulus energy (mechanical, electromagnetic, chemical) into a neurophysiological response by a sensory receptor activity leads to opening/closing of ion channels and change in membrane potential of sensory cell (usually depolarisation, sometimes hyperpolarisation) Graded release: level of reaction is proportional to the release. Sensory receptors: proteins that transduce a physical stimulus into biological signal, e. g. membrane potential, action potential. Rhodopsin (rod cells, responsible for visual signals) Sensory receptors act as filters; filters environmental signals and only responds to a specific type of stimuli, e. g. olfactory receptor only responds to odorants. Transduction can be either mechanical (mechanical force acting on channel, e. g. touch, hearing) or via second messenger (g-protein coupled receptor molecule initiating biochemical cascade, e. g. vision, olfaction, taste) Extracellular anchor is linked to cell channel via extracellular links, and cytoskeleton is connected to channel vis intracellular links molecular deflection of anchor leads to opening or closing of channel.
