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Muscle Physiology. Human Anatomy and Physiology II Oklahoma City Community College. Dennis Anderson. Muscle Tissue. Skeletal Muscle Cardiac Muscle Smooth Muscle. Skeletal Muscle. Long cylindrical cells Many nuclei per cell Striated Voluntary Rapid contractions. Cardiac Muscle.
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Muscle Physiology Human Anatomy and Physiology II Oklahoma City Community College Dennis Anderson
Muscle Tissue • Skeletal Muscle • Cardiac Muscle • Smooth Muscle
Skeletal Muscle • Long cylindrical cells • Many nuclei per cell • Striated • Voluntary • Rapid contractions
Cardiac Muscle • Branching cells • One or two nuclei per cell • Striated • Involuntary • Medium speed contractions
Smooth Muscle • Fusiform cells • One nucleus per cell • Nonstriated • Involuntary • Slow, wave-like contractions
Z line Z line
Tropomyosin Binding Site Troponin
Muscle Contraction Summary • Nerve impulse reaches myoneural junction • Acetylcholine is released from motor neuron • Ach binds with receptors in the muscle membrane to allow sodium to enter • Sodium influx will generate an action potential in the sarcolemma
Muscle Contraction Continued • Action potential travels down T tubule • Sarcoplamic reticulum releases calcium • Calcium binds with troponin to move the troponin, tropomyosin complex • Binding sites in the actin filament are exposed
Muscle Contraction Continued • Myosin head attach to binding sites and create a power stroke • ATP detaches myosin heads and energizes them for another contaction • When action potentials cease the muscle stop contracting
Motor Unit Ratios • Back muscles • 1:100 • Finger muscles • 1:10 • Eye muscles • 1:1
Creatine + ATP Creatine phosphate + ADP Creatine • Molecule capable of storing ATP energy
Creatine + ATP Creatine Phosphate • Molecule with stored ATP energy Creatine phosphate+ ADP
Muscle Fatique • Lack of oxygen causes ATP deficit • Lactic acid builds up from anaerobic respiration
Muscle Atrophy • Weakening and shrinking of a muscle • May be caused • Immobilization • Loss of neural stimulation
Muscle Hypertrophy • Enlargement of a muscle • More capillaries • More mitochondria • Caused by • Strenuous exercise • Steroid hormones
Steroid Hormones • Stimulate muscle growth and hypertrophy
Muscle Tonus • Tightness of a muscle • Some fibers always contracted
Tetany • Sustained contraction of a muscle • Result of a rapid succession of nerve impulses
Refractory Period • Brief period of time in which muscle cells will not respond to a stimulus
Refractory Periods Skeletal Muscle Cardiac Muscle
Isometric Contraction • Produces no movement • Used in • Standing • Sitting • Posture
Isotonic Contraction • Produces movement • Used in • Walking • Moving any part of the body