Sensory Intro & Cutaneous system Flashcards
T/F: most sensory cells do NOT fire AP
True
tonic/phasic: “slow adapting”
tonic
tonic/phasic: “fast adapting”
phasic
tonic/phasic: detect on and off of stimuli
phasic
tonic/phasic: detect sustained stimuli
tonic
stimulation of a sensory nerve produces how many sensations?
only one
abnormal stimulation (punch in eye) can lead to ( )
paradoxical sensations (light)
classification of receptors based on their normal stimulus:
1) mechanoreceptor
2) pain receptors
3) chemoreceptors of taste and smell
4) photoreceptors
5) thermoreceptors
sensory neurons will respond to a subset of stimuli//one region of space detected (ex. cutaneous receptors sense stimuli only in immediate area, visual ganglion cells respond to stimuli in one region of space)
receptive field
stimulation of a receptive field often leads not only to stimulation of the field, but also to inhibition of the surrounding receptive fields
lateral inhibition
serves to sharpen the localization of the response (sharpened discrimination)
lateral inhibition
“two point touch threshold”
lateral inhibition
cutaneous sensor: responsible primarily for touch and pressure
encapsulated
ex. of encapsulated
Pacinian and Meissner’s corpuscles
cutaneous sensor: responsible for touch, pressure, heat, cold, and pain
free nerve endings
ex. of free nerve endings
dendrites around hair follicles (hair movement) and free nerve endings in skin (pain & temp)
most important players for touch in superficial layers (fine touch)
- fast adapting: Merissner’s corpuscle
- slow adapting: Merkel disks
most important players for touch in deeper skin layers (more gross level)
- fast adapting: Pacinian corpuscle
- slow adapting: Rufini endings
fibers carrying the senses of ( ) cross as soon as entering the spinal cord
pain and temperature
fibers carrying senses of ( ) ascend the spinal cord to the base of the brainstem before crossing
touch and proprioception
If the spinal cord lesion is one one side, how will it affect the senses on the two sides of the body?
?
two-point touch thresholds in different parts of the body
sensory acuity
thresholds are much closer for the ( ) than the torse
fingertips
