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Muscles. Types of Muscle. Smooth - involuntary Skeletal - voluntary Cardiac - involuntary. Smooth Muscle. Involuntary Lines digestive system Lines blood vessels Contracts bladder Contracts uterus Few nuclei, no striations Movements involve many muscles at a time. Skeletal Muscle.
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Types of Muscle • Smooth - involuntary • Skeletal - voluntary • Cardiac - involuntary
Smooth Muscle • Involuntary • Lines digestive system • Lines blood vessels • Contracts bladder • Contracts uterus • Few nuclei, no striations • Movements involve many muscles at a time
Skeletal Muscle • Under voluntary control • Moves arms, legs, head • Allows us to change body position, move • Produces most of body heat • Many striations, many nuclei • Pull on bone
Structure of Skeletal Muscle • Draw figure 37.10 in your notes here. • Muscles are made of individual bundles. • Each bundle is enclosed by a sarcolemma • Within each sarcolemma are many sarcomeres
Skeletal Muscle (cont.) • Each sarcomere is bounded by two Z lines • Each sarcomere is made of actin and myosin strands
Sliding Filament Theory • Basic theory of muscle contraction. • Two filaments, actin & myosin, interact within the sarcomere • Length of A band doesn’t change. • I-band and H-zone shorten during contraction. • Filaments slide past each other but do not shorten themselves.
Cardiac Muscle • Found only in heart • Striated like skeletal muscle • Involuntary like smooth muscle • Pushes blood out of the heart