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Muscle Tissue Chapter 10. Functions of Muscular Tissue. Producing body movements Stabilizing body positions Storing and movement of substances in the body Producing heat. Properties of Muscular Tissue. Excitability Contractility Extensibility Elasticity. Types of Muscle.
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Muscle Tissue Chapter 10
Functions of Muscular Tissue Producing body movements Stabilizing body positions Storing and movement of substances in the body Producing heat Properties of Muscular Tissue Excitability Contractility Extensibility Elasticity
Types of Muscle Skeletal Muscle Cardiac Muscle Smooth Muscle
Muscle Attachments Attachment - connective tissue layers extend to attach to bone (tendon or aponeurosis) Insertion - attachment to a movable bone Origin - attachment to stationary bone
Sarcomere Dark(A) & light(I) bands visible with an electron microscope
Contraction of a Skeletal Muscle Motor Unit: A motor neuron and all the muscle fibers it innervates.
Contraction of a Skeletal Muscle Muscle Twitch: Response of a muscle to a single stimulus
Contraction of a Skeletal Muscle Graded Muscle Responses Graded - variation in degree of contraction 1. Frequency of stimulation Wave summation and Tetanus 2. Strength of the stimulus Motor Unit Recruitment More motor units stimulated which leads to more muscle fibers responding.
Muscle Tone Involuntary contraction of a small number of motor units which leads to partial state of contraction of relaxed muscles Keeps muscles firm even though relaxed Essential for maintaining posture
Isotonic and Isometric Contractions Isometric - muscle applies tension but does not move the load Isotonic - muscle changes length load is moved
Muscle Fatigue • Inability to contract after prolonged activity • central fatigue is feeling of tiredness and a desire to stop (protective mechanism) • depletion of creatine phosphate • decline of Ca2+ within the sarcoplasm • Factors that contribute to muscle fatigue • insufficient oxygen or glycogen • buildup of lactic acid and ADP • insufficient release of acetylcholine from motor neurons