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Nervous System breakdown

I). Innervation of joints

Hiltonís Law:

Any nerve serving a muscle producing

movement at a joint also innervates the

joint itself and the skin over that joint.


II). Reflex Arc

Reflex Arc


stimulus receptor
sensory neuron  integration center
motor neuron effector


A). Definition

A reflex is involuntary rapid predictable motor response to a stimulus.

It is a spinal response that occurs without any input from the brain.


B). Necessary Components

1). Receptor

2). Sensory neuron

3). Integration Center:

4). Motor neuron:

5). Effector:


C). Classification

1). Autonomic:

2). Somatic:


D).  Types

1).  Spinal reflexes

a). Stretch & Deep Tendon

bulletControl the rate and amount of stretch by contracting and relaxing muscle.
bulletMuscle tone is adjusted reflexively in response to posture

i).  Stretch Reflex:

bulletMuscle contraction in response to muscle stretch or increased length.

ii).  Deep Tendon Reflex:

bulletMuscle lengthening in response to muscle contraction or shortening.

ie. Patellar (Knee jerk response)


bulletStrike patellar tendon (stimulus)
bulletStretches the quadriceps muscle (receptor)
bulletStimulates muscle spindle (sensory neuron)
bulletAfferent impulse to spinal column (integration center)
bulletImpulses inhibit contraction of antagonist muscle (motor neuron)
bulletResults in contraction of quadriceps and inhibition of hamstring. (effector)

b). Flexor Reflex

bulletWithdrawal of body part in response to a painful stimulus. (either real of perceived)

c). Crossed Extensor Reflex

bulletWithdrawal of body part while simultaneously extending the opposite of the body to maintain support.

d). Superficial Reflexes

bulletResponse to gentle cutaneous stimulation.

ie. Plantar Reflex: