Sensation Flashcards
(24 cards)
extroception
preception of stimuli originate outside body
interoception
perception of stimuli originating inside the body
proprioception
perception of body position and movement
general somatic afferents
exteroceptors and proproiceptors
general visceral afferents
interoception
special visceral afferents
taste, olfaction
special somatic afferent
teloception, vision, audition, vestibular
more brain is devoted to sensation than motor
ok
axon collaterals
branching of axons that may serve separate but related functions (synapse on modulatory neurons, synapse for reflexes)
relay system
sensory info is conveyed via relays. relays allow for modulation of the signal
the chain of neurons are usually described as first order, second order, etc. usually at least 3
third order is often thalamus to cortex
how is membrane permeability altered for photoreceptors
absorption of photons by rods and cones
how is membrane permeability altered for chemoreceptors
ion channels open w/ specific ligand or w/ 2nd messenger
how is membrane permeability altered for mechanorceptors
ion channels are linked w/ cytoskeleton
how is membrane permeability altered for thermoreceptors
unclear- involves TRP family protein
how is membrane permeability altered for nociceptor
unclear- respond to noxious temps, mechanical stess, and noxious chemicals. found in TRP family
receptor potential
changes in the membrane potential in the “receiving” cell
receptor potential is graded based off intensity of the stimulus
receptors in the superficial skin are unique. why?
the sensory transducer is a part of the axon itself.
in many systems, (ears, eyes) there is a specialized cell for sensory
how is stimulus modality detected
“labelled lines”
sensory pathways that, once activated, result in the perception of that lines specific sensation
how is stimulus intensity detected
frequency of APs along a given labelled line
adaptation
response of a receptor to a constantly applied stimulus diminishes w/ time
receptors adapt at different rates
rapid adapters- RP generated at onset of stimulus and w/ removal of stimulus
slowly adapting- pain
how is stimulus location detected
receptive field conveys location
what cranial nerves convey gustatory signals
7 9 10
classification systems
erlanger and gasser
A B C
A is fastest
C is slower
C is unmyelinated
what are the largest and smallest neurons used for
large- proprioception
small- pain/ itch/ temperature
