PHGY 214 Lecture Notes - Lecture 17: Calcium Atpase, Cardiac Muscle, Mecha
8 Dec 2017
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Regulation of contraction: contraction requires ca2+ and cooperation of two proteins, tropomyosin - elongated molecule wrapped around actin. Blocks part of myosin binding site on actin: troponin. Regulating intracellular ca2+ free ca2+ concentration is low in cells, ca located in sr, sr is hollow on inside so it can contain fluid and ca: sarcoplasmic reticulum (a form of endoplasmic reticulum) wraps each myofibril, contains ca2+-atpase. Excitation-contraction coupling =a combo of electrical and mechanical event s (2) ap (3) contraction (generating force) Na: ach binds to receptors on motor end plate = contains ligand. Epp gated na and k chan, nicotinic receptor receptor type nicotinic. Na passes thru easier then k creating potential, na chan opens: depolarization creates end-plate potential (epp, graded can trigger an action potential, ap triggers (dihydropyridine or dhp receptors) = v. g. receptors. In cardiac muscle, dhp lets ca into cell also. Ca2 role of acetylcholinesterase deactivates ach at neuromuscular junction.
