OTHY200 Lecture Notes - Lecture 10: Frontal Lobe, Lower Motor Neuron, Motor Neuron
Document Summary
Week 10 motor neurons and descending pathways. Sends signals from brain to the lmn"s in the anterior horn of the spinal cord. Majority of the umn"s are in primary motor area (m1), others come from nearby secondary motor areas (premotor cortex, supplemental motor cortex) These areas plan, program, and execute upcoming movements. Have motor neuron axons in the cns. Lesions: spasticity, rigidity, hyperreflexia, hypertonia (increased muscle tone, resulting lack of flexibility: medial upper motor neurons postural control/ gross movements groups, lateral upper motor neurons fine control/ distal groups (hands/feet) Conveys signals from umn"s in the anterior horn of the spinal cord to the skeletal muscle fibres. Call bodies of lmn located in the anterior horn of spinal cord and motor. Have motor neuron axons in the pns. Lesions: less stimulation with muscle: muscle weakness, flaccidity, hypotonia (state of low muscle tone, involving reduced muscle strength) Axons project to intrafusal fibres in the muscle spindle.
