Exam 2: Ch 7 Book Flashcards
sensory input is gathered constantly from…
environment
within the body
modality
each category of sensation
touch, light, sound
interoreceptive receptors
respond to signals from within the body
transmit to brain subconsciously
proprioceptors
monitor positions of muscles/joints,
sensory receptors could be…
neurons or epithelial cells
electrotonic spread or AP
could be either
primary afferent neuron
neuron whose axon carries signal to CNS
2 general features of sensory receptors
highly selective for specific kind of energy
sensitive to selected modality (light or touch)
transduction
process by which receptor cells change stimulus energy into energy of a nerve impulse
rhodopsin
visual pigment in photoreceptor cells
protein opsin coupled to a retinal (light absorbing molecule)
what does rhodopsin do
capture energy from photons of light, transient structural change
cascade of enzyme activity changing state of ion channels in receptor cell membrane
final step in all sensory receptors
opening or closing of ion channels
3 steps of sensory transduction
detecting stimulus
amplification of stimulus
encoding stimulus into electrical signals
threshold of detection
weakest stimulus that produces a response in a receptor half of the time
transduction of all sensory modalities with 7 transmembrane helices requires
G proteins
ex. rhodopsin in rods/cones
