The Somatic Nervous System Flashcards
Which division of the NS is the SNS part of?
Peripheral - uses motor and sensory neurons.
Describe the motor and sensory neurons.
Motor - voluntary control via skeletal muscle.
Sensory - transmits general sensation (pain, touch, temperature, proprioception).
What are the four types of neurons?
Unipolar.
Bipolar.
Pseudounipolar.
Multipolar.
What makes peripheral nerves resilient?
They are protected by 3 layers of CT.
Epineurium, Perineurium, Endoneurium.
Describe the myelin sheath.
A lipid and protein substance.
Secreted by Schwann cells.
Increases velocity of impulse conduction by insulation.
Define dermatomes.
An area of skin supplied by a single spinal nerve.
Define myotomes.
A part of muscle supplied by a single spinal nerve.
One muscle myotome may involve multiple spinal segments.
Describe motor end plates.
Forms NMJs.
Describe the parts of the spinal nerve.
Roots - sensory OR motor.
Spinal nerves - sensory AND motor.
Rami - sensory AND motor.
Describe the somatic reflex arc.
The interpretation of a sensory detection in the CNS (motor response).
What parts of the body do the ventral rami connect to?
Anterolateral trunk and limbs.
What parts of the body do the dorsal rami connect to?
Back.
Where does the spinal nerve exit?
Through intervertebral foramen.
What are the four types of spinal plexuses?
Cervical.
Brachial.
Lumbosacral.
Coccygeal.
Describe a wrist drop.
Caused by radial nerve palsy (supplies extensors of the elbow and wrist).
