BIOL 1117 Lecture Notes - Lecture 19: Vascular Plant, Desmosome, Cardiac Muscle Cell
10 Nov 2016
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They are not under conscious control: cardiac muscle : slow twitch. Also known as cardiomyocytes and are found in the heart i: must function while we are both awake and asleep iii. Can contract is a routine way without outside nerve excitation: has a pace-maker structure : set regular heartbeat, heart contracts with an independent rhythm: autorhythmic, autonomic nervous system i. ii. Does not send nerve fibers to the heart: can increase or decrease heart rate and contraction strength. Striated with thick and thin filaments: smaller sarcoplasmic reticulum and larger t tubules iii. Intercalated discs: contain electrical gap junction that allow each myocyte to stimulate neighboring myocytes, have desmosomes to help hold the myocytes together, smooth muscle i. ii. iii. iv. Composed of myocytes that have fusiform shape with one nucleus. No visible striations: thick and thin filaments are present but not aligned. Z discs are replaced by dense bodies: array of protein masses in cytoplasm.
