Fibrillation of skeletal muscle is associated with all except: March 2011
Ans. D: Strong stimulusWhen the motor nerve to a skeletal muscle is cut, it causes disuse atrophy of the muscle, complete paralysis of the muscle, fibrillations, abnormal excitability of the muscle and increased sensitivity to circulating acetylcholine (denervation hypersensitivity)FibrillationIt happens when muscle fibers lose contact with their innervating axon producing a spontaneous action potential, "fibrillation potential" that results in the muscle fiber's contraction.These contractions are not visible under the skin and are detectable through needle electromyography (EMG) and ultrasound.Fibrillations do not occur in healthy individuals.They are a major symptom in acute and severe peripheral nerve disorders, in myopathies in which muscle fibers are split or inflammed, and lower motor neuron lesions.FasciculationsThey are visible spontaneous contractions involving small groups of muscle fibers.Fasciculation does not necessarily denote pathology, as does fibrillation, although it can be seen in lower motor neuron lesions as well.
Long time after denervation
Hypersensitivity to acetylcholine
Lot of receptors over entire muscle cell membrane
Strong stimulus