Somatosensory System - Quiz 12

exteroreceptors

o Location: Skin

o Function: Sensitive to light touch, coarse touch, nociception, temperature

Meissner's corpuscles

· Light touch, vibration

· Quick on/off

Pacinian corpuscles

· Transient pressure, vibration

· On during pressure, off when pressure removed

ruffini nerve ending

· Stretch of skin, sustained pressure on skin

· Some perception of heat

Merkel's disks

· Prolonged or sustained pressure

Krause's end organ

Senses cold

free nerve endings

Convey info for coarse touch, nociception, temperature

receptive field

Area of skin innervated by a single neuron

receptive fields

_________ ______ are smaller distally which allows for signals about sensation to be more precise (e.g. fingers have more fine perception of sensation than your torso)

myotatic reflex

What is the below an example of?

o Hammer hits tendon, sending afferent signal

o Integrating center receives afferent signal

o Efferent signal is sent to quads inducing a contraction in addition to an efferent signal being sent to the hamstrings causing them to relax, allowing extension of leg (reciprocal inhibition)

proprioceptive

______________ receptors are in muscle spindle, golgi tendon organs, and joint receptors

muscle spindles

o In the muscle belly itself

o Responsive to stretch

muscle spindles

o Provides CNS information about muscle length and rate of change in muscle length as well as feedback about unconscious proprioception

o Afferent and efferent fibers present allowing CNS to be informed about muscle length as well as adjust length if required

golgi tendon organ

o Located at or near the musculotendinous junction

o Responsive to tension on a tendon

golgi tendon organ

§ Highly active during active muscle contraction but responds to both active or passive movement

§ Reacts to weight, heaviness, or force placed on muscle/tendon

§ Provides feedback about unconscious proprioception

golgi tendon organ

Fill in the blank:

o Reverse myotatic reflex (autogenic inhibition)

§ Stimulation of the _____ ______ _____causes inhibition of the agonist

§ Helps to prevent injury

§ Slower than spindle, but can override spindle

ligament receptors

Function is analagous to golgi tendon organs but operate in ligaments

Ruffini endings

Operate in joint capsules and signal extremes of joint range

Paciniform corpuscles

Respond to movement, inactive at rest in any joint position