Unformatted text preview: • calmodulin complex activates smooth muscle myosin ATPase through myosin light chain kinase (MLCK) (Phosphorylation of protein plays a key role in smooth muscle contraction) Fig. 12-26 • Actin regulation through caldesmon Fig. 12-27 • ATP hydrolyzed --> energized myosin • very slow ATPase activity • therefore, confraction-time is much longer, but sustain contraction for much longer duration. • energy (ATP) requirement is 1/10 to 1/30 of skeletal muscle fibres B.4. Differences in Muscle Contraction Sequence As Compared to Skeletal Muscle : Table 12-3- unitary smooth muscle can be stimulated by . .. 1) Autonomic Nervous System 2) Hormones 3) Changes in ECF composition (pH, concentration of metabolites) 4) Mechanical stretch 5) Spontaneous changes in membrane potential - cyclical changes in ion permeability....
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- Fall '09
- muscle fibres, smooth muscle contraction