01:119:116 Lecture Notes - Lecture 20: Taste Receptor, Signal Transduction, Middle Ear
11 Oct 2016
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Concept 50. 1: sensory receptors transduce stimulus energy and transmit signals to the cns. Fig 50. 3: two types of sensory receptors: neuronal and non-neuronal which remain at resting potential until stimulated: Naked dendrites sense impulse directly and relay signal to cns. Receptor molecules sense and relay signal to sensory neutrons, then to cns. Receptor potential: changes in membrane potential of receptor caused by flow of ions across membrane of sensory receptor. Sensory receptor: unstimulated maintains resting potential, stimulated. Depolarized, becomes more positive, na+ goes from outside to inside. When receptor potential reaches certain threshold level, current triggers action potential in associated sensory neuron. Perception: brain distinguishes stimuli from different receptors based on area in brain where action potential arrive. Fig 50. 4: a larger receptor potential (e. g. greater pressure) results in more frequent action potentials. Stronger the stimulus, greater the amount of depolarization. : a. p. conducted from eye to brain has 100000x the energy than photons of light that triggered it.
