motor nerve
Muscle-commanding fiber
A motor nerve carries signals from the brain or spinal cord to muscles, triggering movement.
These nerves form the output side of the nervous system—sensory nerves bring information in, motor nerves send commands out.
Damage to motor nerves causes weakness or paralysis in the affected muscles.
Neuron's signal-sending projection
Nerve pathway for involuntary responses
- stretch reflexMuscle contracts when lengthened
- afferentConveying toward central point
- efferentConveying outward from center
- interneuronNerve cell connecting others
stimulus · response · involuntary · knee jerk · tendon reflex · reflex hammer · rapid response
Fibers tensing and shortening
- movementChange in position
- impulseSudden urge to act
- voluntary movementSelf-initiated bodily action
- coordinationOrganized cooperative movement
locomotion · stimulation · activation · neuromuscular · action potential · acetylcholine · neurotransmission · excitation
Loss of muscle function
- atrophyWasting from disuse
- weaknessDeficiency in force
- ALSMotor neuron disease
- polioParalytic viral infection
denervation · Bell's palsy · fasciculation · muscle wasting · electromyography · regeneration · demyelination · Guillain-Barré
axon
Neuron's signal-sending projection
reflex arc
Nerve pathway for involuntary responses
- stretch reflexMuscle contracts when lengthened
- afferentConveying toward central point
- efferentConveying outward from center
interneuron · stimulus · response · involuntary · knee jerk · tendon reflex · reflex hammer · rapid response
muscle contraction
Fibers tensing and shortening
- movementChange in position
- impulseSudden urge to act
- voluntary movementSelf-initiated bodily action
coordination · locomotion · stimulation · activation · neuromuscular · action potential · acetylcholine · neurotransmission · excitation · skeletal muscle
paralysis
Loss of muscle function
polio · denervation · Bell's palsy · fasciculation · muscle wasting · electromyography · regeneration · demyelination · Guillain-Barré · tremor
- nervous systembrain, neurons, spinal cord, axon, dendrite
- nervesspinal cord
- Neurophysiologyaction potential, neurotransmitter, presynaptic, depolarization, repolarization
- nerve cellsbrain cell, axon, dendrite, glia, soma
- cranial nerves