13 - Skeletal Muscle Types - there exist 3 different types...

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Unformatted text preview: Skeletal Muscle Types - there exist 3 different types of muscle fibers based on their differences in ATP metabolism and their speed of contraction (i.e. myosin-ATPase activity) (Table 8-1). Slow oxidative (type I) - these fibers contract relatively slowly and rely heavily on oxidatve phosphorylation as their main source of ATP. Consequently they have many mitochondria, a rich blood supply, and an abundance of myoglobin. Fast oxidative (type IIa) - these fibers contract relatively quickly and rely heavily on oxidatve phosphorylation as their main source of ATP. Consequently they have many mitochondria, a rich blood supply, and an abundance of myoglobin. Fast glycolytic (type IIb) - these fibers contract very quickly and rely heavily on glycolysis as their main source of ATP. Consequently they have few mitochondria, a limited blood supply, an abundance of glycogen, and a relatively small amount of myoglobin. Smooth Muscle - these muscle fibers are located in the walls of hollow organs and tubes such as blood vessels and the intestines. Their morphology is distinct from that of skeletal muscle cells. They are small, unstriated and lack the distinct sarcomeres that are present in skeletal muscle cells. Their contractile apparatus is made up of thin filaments that slide relative to stationary thick filaments in response to a rise in cytosolic Ca++ (Figure 8-28,8-29). ...
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This note was uploaded on 10/29/2009 for the course NPB NPB 101 taught by Professor Weidner/wingfield during the Fall '08 term at UC Davis.

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