EHS 350 Lecture Notes - Lecture 4: Endoplasmic Reticulum, Myasthenia Gravis, Neuromuscular Junction
19 Jun 2017
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Document Summary
Sarcoplasmic reticulum skeletal muscle cells have network of membrane with spaces called sarcoplasmic reticulum specializes in storing, releasing and reabsorbing calcium. When action potential reaches end of neuron it causes acetylcholine release into gap b/w neuron and muscle fibers synaptic vesicle release when action potential causes calcium release. Myasthenia gravis autoimmune disease body attacks acetylcholine receptors charge difference across plasma membrane in resting cell. When ach attaches to receptors - it opens sodium channels in sarcolemma. When these channels open na+ leak into cell making underside of sarcolemma positive instead of negative. Many sodium gates along entire sarcolemma are voltage regulated. When inside becomes positive it opens na+ channels quicky close na+ channels and open potassium (k+) channels potassium goes thru channels and leaves cells - muscle fiber at that spot is negative again. Excitation - contraction coupling everything from creation of action potential at motor end plate due to ach receptor attachment.
