Somatic Sensory System Flashcards
Sensory receptors differ by
shape of ending
axon diameter
sensitivity
presence/absence of myelin
classification of peripheral nerves (fiber diameter)
A-alpha, A-beta, A-gamma, A-delta, B, C
or
Ia, Ib, II, III, IV
A-alpha
alpha-motoneurons
muscle spindle primary endings
golgi tendon organs
touch
A-beta
touch
kinesthesia
muscle spindle secondary endings
A-gamma
touch
pressure
gamma-motoneurons
A-delta
pain
crude touch
pressure
temperature
B
preganglionic autonomic
C
pain touch pressure temperature postganglionic autonomic
Ia
muscle spindle primary endings
Ib
golgi tendon organs
II
touch
kinesthesia
muscle spindle secondary endings
III
pain
crude touch
pressure
temperature
IV
pain
touch
pressure
temperature
4 attributes of a stimulus
- modality
2 intensity - duration
- location
what sensory: dorsal column medial lemniscal pathway
fine touch, proprioception
how does DCML travel
ipsilaterally in spinal cord to medulla
crosses contralateral side to thalamus
then sensory cortex
what sensory: anterolateral (spinothalamic) pathway
coarse touch
pain
temperature
how does anterolateral travel
enters spinal cord, synapses onto another neuron
and then crosses to opposite side of spinal cord
travels contralaterally to brain stem, thalamus, sensory cortex
what sensory: spinocerebellar tract
proprioceptive information to cerebellum
what receptor provides cutaneous feedback
skin mechanoreceptors
Superficial receptors
Meissner’s - spatial acuity
Merkel’s
Deeper receptors
Ruffini - detect movement, skin stretch
Pacinian
Slow adapting
Merkel disk receptors
Ruffini endings
Rapid adapting
Meissner’s corpuscles
Pacinian corpuscles
