TheMuscularSystem - The Muscular System Three types of...

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The Muscular System Three types of muscle Skeletal muscle- attaches to and moves bone –is striated –is voluntary Smooth muscle- located in the walls of internal structures –non-striated –Involuntary Cardiac muscle Functions of Muscle Tissue Motion Movement of substances within the body Stabilizing body position and regulating organ volume –maintaining posture –maintaining food storage in stomach Heat production –muscle contraction generates 85% of the body’s heat Characteristics of Muscle Tissue Excitability- receive and respond to stimuli Contractility- ability to shorten and thicken Extensibility- ability to stretch Elasticity- ability to return to its original shape after contraction or extension General Anatomy of Skeletal Muscle origin - stationary end of muscle attachement insertion - mobile end of attachment belly - thicker middle region Structure of Skeletal Muscle Connective tissue components fascia- sheets or bands of fibrous c.t. around organs, muscle and beneath the skin superficial fascia (subcutaneous layer)- composed of areolar c.t. and adiose tissue and is located under the skin deep fascia- composed of dense, irregular c.t. that holds muscles together and from which the various subdivisions of muscle c.t. are derived Production of ATP in Muscle Fibers Muscles have three ways to produce ATP –from creatine phosphate-unique to muscle tissue –anaerobic cellular respiration using glycogen –aerobic cellular respiration using glycogen, fatty acids, and amino acids
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Energy for Contraction •ATP- immediate source of energy that last for only 5 seconds •Creatine Phosphate- high energy molecule that is used to make ATP. –Makes enough energy to last for about 15 seconds •Glycogen- storage form of glucose –with oxygen can use the glycolytic-Krebs cycle pathway to produce ATP (aerobic respiration) •most efficient method of energy production –without oxygen can use glycolytic pathway with end product of lactic acid (anaerobic respiration) •can provide enough energy for 30 seconds of maximal activity All or None Principle •Threshold stimulus- the weakest stimulus from a neuron that can still initiate a contraction. •All-or-none principle- when stimulated, a motor unit will contract to its fullest; a motor
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TheMuscularSystem - The Muscular System Three types of...

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