Other Muscles Types

Other Muscles Types - in oxygen supply. Smooth Muscle...

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Other Muscles Types Cardiac Muscle Cardiac muscle cells are found exclusively in the heart. These cells are shorter and thicker than skeletal muscle cells. They also branch repeatedly and and are linked to each other at specialized junctions called intercalated discs . These intercalated disks contain both gap junctions that allow individual cells to communicate with their neighbors very quickly and desmosomes that keep the cells from pulling apart during contraction of the heart muscle. In contrast to skeletal muscle which requires nervous system input to contract, cardiac muscles are autorhythmic . The cardiac muscle uses aerobic respiration almost exclusively and has very large mitochondria to continuously produce ATP. This makes it resistant to fatigue but very vulnerable to interruptions
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Unformatted text preview: in oxygen supply. Smooth Muscle Smooth muscles are long and somewhat bulbous in shape. They have no visible striations (hence the term smooth). The lack of striations indicates that smooth muscles do not have myofilaments that are organized into sarcomeres. Instead the myofilaments are attached to dense bodies scattered throughout cytoplasm and on the cell membrane. Furthermore, smooth muscles have little SR and no T-tubules and the calcium necessary for contraction comes exclusively from the extracellular fluid. The innervation of smooth muscle is from the autonomic nervous system and the cells respond to either ACh or norepinephrine . The response of smooth muscles to these neurotransmitters varies depending upon their location....
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