Lecture 9 Pt. 1: Efferent Nervous System

1)What is Amyotrophic Lateral Sclerosis (Motor Neuron Disease)?

• characterized by hyperreflexia (overractive reflexes) and amyotrophy (muscle wasting)

• symptoms include asymmetric hand weakness, diminishing of muscle strength and bulk, fasciculations (muscle twitching)

• eventually occurs in respiratory muscles, causing pulmonary infection

• resulting from loss of upper motor neurons in coricospinal tracts and lower motor neurons in ventral horns of spinal cord

• 5-10% of cases are genetic

• proposed causes: genetic content of SOD1 on chromosome 21 leading to reduced capacity to detoxify free radicals; protein misfolding of SOD1 triggers injurious protein response