BIOL 030 Lecture Notes - Lecture 12: Myocyte, Autonomic Nervous System, Skeletal Muscle
17 Sep 2020
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Document Summary
Where the nerve fibre transmits the signals to the muscles. Skeletal muscle only contracts when stimulated by a nerve. Denervation atrophy is shrinkage of a paralyzed muscle when nerve is disconnected. Cells are myocytes, which are not as long and fibrous as skeletal muscles. Involuntary we don"t have to think about them. Receive innervation from the autonomic nervous system. Muscle cells of a given chamber must contract in unison. Myocyte is joined at its end to other myocytes by intercalated discs. Mechanical junctions that keep myocytes from pulling apart. Contractions must last long enough to expel blood from the heart. Striated like skeletal muscle (myocytes, called cardiocytes, are shorter and thicker) Can contract without need for nervous stimulation. Contains a pacemaker, which sets off a wave of electrical excitation in a rhythm. Wave travels through muscle and triggers contraction of heart chambers. Slower than other muscle types, however, it can remain contracted for a long time without fatigue.
