somatic nervous system

components of the somatic nervous system

(voluntary control)

afferent nerves- reception of internal and external stimuli

incoming info coordinated by spinal cord, somatomotor cortex and cerebellum

efferent transmit impulses from cns to skeletal muscles

components involved in the somatic

joints, skin, skeletal muscle, somatosensory fibers, somatomotor fibers

signal transduction route- sensory division

• sensory inputs to SC and brain

• SC initiate voluntary motor control

• SC also sends info to brain to initiate voluntary motor control

• SC and brain sends response to contract muscle

signal transduction route- motor division

• spinal cord initiates response via lower motor neurons or upper motor neurons of the somatomotor cortex and brain stem pathways make contact with spinal lower neurons

• somatomotor cortex initiate voluntary movement and modulate muscle/reflex activity

patella reflex

1. tap/bend the patella tendon

2. stretch receptors in muscle simulated

3. sensory neuron in muscle send signal spinal cord

4. spinal cord detects signal and sends response

5. motor neuron carry response to muscle from spinal cord

6. quads muscle contracts

meisnyer corpuscles

skin light touch

merkers disk

skin touch and texture

pacinian corpuscle

pain and deep pressure

ruffini corpuscle

stretch / kinesthesia

free nerveending

pain