1. Pgs. 218-219

2. Muscular Dystrophy Weakening/breakdown of the voluntary muscle cells A group of over 30 types of inherited muscular diseases Duchenne’s MD: Recessive; Sex-linked More common in boys Affects a protein that maintains the sarcolemma

3. Disorders of the Neuromuscular Junction Myasthenia Gravis: Auto-immune disease Antibodies destroy or block the receptor sites on the sarcolemma Results in failed transmission of nerve impulses = atrophy Eaton-Lambert Syndrome: Problem w/Calcium channel in axon terminals Results in decreased release of Ach Potentially caused by cancer Black Widow venom: Causes a complete depletion of Ach Leads to temporary paralysis

4. Growing and Aging Gross motor skills dominate early in life followed by fine motor skills Peak performance is around adolesence Training improves certain skills Older individuals begin to lose muscle mass Decrease of about 50% by age of 80 Can counteract this with exercise; weight lifting Failure to use muscles can result in loss of muscle mass or atrophy