01:119:116 Lecture Notes - Lecture 21: Sliding Filament Theory, Rigor Mortis, Troponin
12 Jun 2017
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Lecture 21: musculoskeletal system: vertebrate skeletal muscle. A. a)muscle tissue generates mechanical force in response to nervous system. T (transverse) tubules connect impulses to sarcoplasmic reticulum (sr) (a. f. 3) B. b)thin filaments have 3 types of proteins: (b. b. 1) B. d)actin and myosin proteins: muscle appears striped (striated: sarcomere. C. b)overlapping thick + thin, 100s connect to form myofibril. C. c) z lines join sarcomeres at ends. C. f) thick filaments anchor at m, centered in sarcomere. Thick and thin filaments slide and break old connections (c. g. 2) Form new ones sarcomere gets shorter (c. g. 3) Distance between z lines change overlap changes not length of filament: sliding filament model. Muscle cells are large: t-tubules facilitate ap to affect myofibrils. Ap travels: plasma membrane down t-tubule sr. Sr has high ca, ca channels open and ca enters cytosol (later ca pump returns ca to sr) D. a) muscle fiber at rest: tropomyosin covers myosin binding sites of actin.
