somatosensory exam 2

lower motor neuron: paralysis, relfexes, atropy, features

p: flaccid, R: decreased: A: severe F: fasciculations

loss of cortico input, babinksi sign

change of reflex activity, extensor plantar response instead of flexor

upper motor nerson damage: paralysis: reflexes: atropy, and featuers

P: spastic, R: increased: A: minimal F: babinksi sign

Ataxia sensory: location of lesion, visual input and deficit

lesion in PC/ML visual input helps, deficit in fast SS

ataxia motor location of lesion, visual input and deficit

lesion in cerebellar column, visual input odesnt help, deficit: intention tremor

merkle cell

neurite complex, peripheral sensory neuron, texture and braille (mechano)

meissner corpuscle

has lamellae associated with peripheral structure, deep flutter and motion helps maintain grip (mechano)

pacinan corpuscles

many membrane layers and fluid , detect vibration (mechano)

golgi tendon organ

(proprio) located at muscle detect muscle/tendon boundary, detects muscle detection

muscle spindle

located depp in muscle, detects muscle stretch (proprio)

ruffini corpuscle

(proprio) detect sin stretch when bending a joint

nocioceptors

detect painful stimuli causing tissue damage

polymodal nocioreceptor

respond to one or more stimuli, subtypes respond harsh mechanical stimuli, extreme temperatures or chemicals

nociceptors peripheral

ending are free/bare, no peripheral associated strucutre or cells, proteins in membrane determine what nocioceptors respond to

thermoreceptors

detect temperatures that aren not harmful, warm or cool, have free nerve ending and relay on protein receptors in the peripheral endings

somatosensory receptor propgration speed fastest to slowest

proprioceptors, mechanoreceptors, thermoreceptors

peripheral receptors arrangementn

SS receptors have their cell bodies in the dorsal root ganglia or trigeminal ganglia

dermatomes

skin regions that are innervated by dorsal root ganglia

shingles

rash caused by herpes zoster virus that causes chicken. pox. stays dormant in SS neurons after the chicken pox clears up.

receptive fields

area that when stimulated leads to membrane potential change in a specefic neuron.

small receptive field

higher resolution, fingers, lips, tongue

first pain

Adelta fibers and helps us localize painful stimulus, intensity is pretty high but doesnt last long

second pain

unmyelinated fibers, achy, burning, punishing pain that is perceived slowly but last longer, reminds us to not engage in th behavior that caused the pain and to take care of injury

slow SS characterisitcs

free nerve endings with specefic protein receptors and large receptive fields, slower conduction veloctiies, larger number of synaptic relays, less percise