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Muscular System X Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Muscular System Main function of a muscle: Contraction (shortening) Because muscles can contract: The main functions of the muscular system are: Movement Maintains Posture Stabilizes Joints Generates Heat Controls Openings (sphincters) Expressions Protection (reflexes) Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Three basic muscle types are found in the body Skeletal muscle Cardiac muscle Smooth muscle can you distinguish which is which? Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Characteristics of Muscles Skeletal and smooth muscle cells are elongated ***(a muscle cell is also referred to as a muscle fiber) Some skeletal muscle cells can be up to a foot long in length All muscles share some terminology If you see myo- mys- or sarc- you think MUSCLE! Prefixes myo and mys refer to “muscle” Prefix sarco refers to “flesh” Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Comparison of Skeletal, Cardiac, and Smooth Muscles Table 6.1 (1 of 2) Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Comparison of Skeletal, Cardiac, and Smooth Muscles Table 6.1 (2 of 2) Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Terminology Review Endo- Inside, Within (endoskeleton) Peri- Around, surround (perimeter) Epi- On, over, above (epidermis) Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Our Focus: SKELETAL MUSCLE (Striated) Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Skeletal Muscle Characteristics Attached to the skeleton Attached by tendons to bones (or aponeuroses) Cells are multinucleate (many nuclei) Striated (have visible banding) Strong force Tire easily (muscle fatigue) Voluntary—you control them (exception = reflexes) Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue Wrappings of Skeletal Muscle Cells are surrounded and bundled by connective tissue Endomysium—encloses a single muscle fiber Perimysium—wraps around a group of muscle fibers forming a fascicle (bundle of muscle fibers) Epimysium—covers the entire skeletal muscle (many fascicles) Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Connective Tissue Wrappings of Skeletal Muscle Figure 6.1 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Skeletal Muscle Attachments Epimysium blends into a connective tissue attachment at the ends of muscles 2 Types 1. Aponeuroses—sheet-like structures of connective tissue (sometimes referred to as fascia) Attach muscles to bones, cartilages, or connective tissue coverings Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Skeletal Muscle Attachments 2. Tendons—cord-like structures Mostly collagen fibers Often cross a joint due to toughness and small size Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings