Motor systems Flashcards
definition: motor unit
one alpha motor neuron plus all the skeletal muscle fibers it innervates
definition: fasciculation
visible twitches of muscle that can be seen as ripples under the skin - can involve one or more motor units
what contributes to the cause of fasciculations?
sensitivity of un-innervated receptors to circulating Ach
definition: fibrillation
spontaneous activity within single muscle fibers - not visible clinically
what are the symptoms of UMN damage?
- spasticity 2. overactive DTR 3. Positive Babinski sign
what are the effects of a transection of the spinal cord with respect to
- loss of voluntary movement for muscles innervated by spinal segments below level of transection 2. loss of “true” sensation, anesthesia, for areas innervated by sensory neurons below level of transection
what are the INITIAL effects of spinal cord transection?
- spinal shock 2. flaccid paralysis 3. areflexia 4. loss of autonomic function
what are the effects of spinal shock?
initial flaccid paralysis due to damage to descending motor pathways