The Muscular System. Muscle tissue is one of the 4 tissue types in vertebrates Muscle

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1 The Muscular System

2 The Muscular System Muscle tissue is one of the 4 tissue types in vertebrates Muscle

3 The Muscular System Muscle tissue is one of the 4 tissue types in vertebrates Muscle Nervous

4 The Muscular System Muscle tissue is one of the 4 tissue types in vertebrates Muscle Nervous Epithelial

5 The Muscular System Muscle tissue is one of the 4 tissue types in vertebrates Muscle Nervous Epithelial Connective

6 The Muscular System Function Produce movement Maintain posture Stabilize joints Generate heat

7 The Muscular System Muscle tissue is composed of cells that can contract Muscles are responsible for all types of body movement Contraction = Shorten

8 Muscle Characteristics Muscle cells are elongated (muscle cell = muscle fiber) Muscle contraction is due to the movement of muscle microfilaments Prefix myo and mys refers to muscle

9 The Muscular System 3 basic muscle types Skeletal muscle

10 The Muscular System 3 basic muscle types Skeletal muscle Cardiac muscle

11 The Muscular System 3 basic muscle types Skeletal muscle Cardiac muscle Smooth muscle

12 Skeletal Muscle Attached by tendons to bones Cells are multinucleate (more than one nucleus per cell) Striated (have visible banding) Voluntary Cells are bundled together by connective tissue

13 Connective Tissue Wrappings of Skeletal Muscle Endomysium surrounds individual muscle fibers Fascicle a bundle of muscle fibers

14 Connective Tissue Wrappings of Skeletal Muscle Perimysium surrounds muscle fascicles Epimysium covers the entire skeletal muscle

15 Connective Tissue Wrappings of Skeletal Muscle The epimysium blends into a connective tissue attachment Tendon cord-like structure connecting bone to muscle Ligaments connects bone to bone at joints Cartilage flexible connective tissue between bones and joints

16 Smooth Muscle No striations (smooth) Spindle-shaped cells Single Nucleus Involuntary Slow, sustained, and tireless movement Found mainly in the walls of hollow organs

17 Cardiac Muscle Has striations Usually has a single nucleus Involuntary Found only in the heart Steady pace

18 Muscle Contraction Skeletal muscle fibers are composed of myofibrils

19 Muscle Contraction Skeletal muscle fibers are composed of myofibrils Each myofibril is made up of protein filaments

20 Muscle Contraction Skeletal muscle fibers are composed of myofibrils Each myofibril is made up of protein filaments Thick filaments = myosin Thin filaments = actin

21 Muscle Contraction Sarcomere = the basic unit of striated muscle tissue

22 Muscle Contraction Myosin filaments have heads

23 Sliding filament Theory of Muscle Contraction A muscle contracts when the thin filaments in the muscle fiber slide over the thick filaments.

24 Muscle Contraction Movement of Actin Filament Actin Binding sites Myosin Cross-bridge Copyright Pearson Prentice Hall

25 Muscle Contraction Powered by ATP, the myosin cross-bridge changes shape and pulls the actin filament toward the center of the sarcomere. Copyright Pearson Prentice Hall

26 Muscle Fatigue When a muscle is fatigued, it is unable to contract Most common reason is oxygen debt (temporary lack of oxygen availability) Oxygen must be repaid to tissues to remove oxygen debt.

27 Muscles & Movement Opposing muscles contract and relax

28 Muscles & Movement Opposing muscles contract and relax

29 Muscles & Movement Movement is due to a muscle moving an attached bone

30 Muscles & Movement Muscles are attached to at least 2 points Origin where muscle originates. Fixed attachment Insertion moves with contraction

31 Types of Muscles Prime mover muscle with the major responsibility for a given movement Antagonist muscle that opposes or reverses a prime mover Synergist muscle that aids a prime mover and helps prevent rotation