chapter 9-1: muscular system intro Essential Question: Outline the Principle of Complementarity for the 3 types of muscle tissue (skeletal, cardiac, smooth). chapter 9-1: muscular system intro Learning Targets Identify structure and function of 3 types of muscle tissue. Identify the functional characteristics of muscle tissue. List the functions of muscle Describe the anatomy of skeletal muscle

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Muscle Overview There are three types of muscle tissue found in the body: Cardiac Smooth Skeletal These types differ in structure, location, function, and means of activation.

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Muscle Similarities Skeletal and smooth muscle cells are elongated and are called muscle fibers. Muscle contraction depends on two kinds of myofilaments actin myosin Muscle terminology Sarcolemma: muscle plasma membrane Sarcoplasm: cytoplasm of a muscle cell Prefixes: “myo”, “mys”, and “sarco” all refer to muscle

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Functional Characteristics of Muscle Tissue Excitability, or irritability: the ability to receive and respond to stimuli Contractility: the ability to shorten forcibly Extensibility: the ability to be stretched or extended Elasticity: the ability to recoil and resume the original resting length

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1. Cardiac Muscle Tissue Only in the heart Is striated but is not voluntary Contracts at a fairly steady rate set by the heart’s pacemaker Cardiac muscle is responsible for moving the blood through the body Neural (nerve) controls allow the heart to respond to changes in bodily needs

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2. Smooth Muscle Tissue Found in the walls of hollow visceral organs It is not striated and is involuntary Contracts much slower than the other two types of muscle Smooth muscle helps maintain blood pressure, and squeezes or propels substances (i.e., food, feces) through organs and channels

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3. Skeletal Muscle Tissue Muscles that attach to and cover the bones/ skeleton Has obvious stripes called striations Is controlled voluntarily (by conscious control) Contracts rapidly but tires easily Skeletal muscles are responsible for all locomotion also maintain posture, stabilize joints, and generate heat Is extremely adaptable and can exert a variety of forces

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3A. Skeletal Muscle Each muscle is a discrete organ composed of: Muscle tissue Blood vessels One artery and at least one vein Nerve fibers Each muscle has a nerve ending Connective tissue Connects to the bone by tendons Three connective tissue sheaths surround various parts

3A. Skeletal Muscle The three connective tissue sheaths are: Endomysium: fine sheath of connective tissue surrounding each muscle fiber Perimysium: fibrous connective tissue that surrounds groups of muscle fibers called fascicles Epimysium: an overcoat of connective tissue that surrounds the entire muscle