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Medicine LibreTexts

7: Muscles

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  • Objectives

    After completing this section, you should know:

    • The structure of smooth, cardiac and skeletal muscle and where they are found.
    • What the insertion and origin of a muscle is.
    • What flexion and extension of a muscle means.
    • That muscles usually operate as antagonistic pairs.
    • What tendons attach muscles to bones.

    • 7.1: Website
    • 7.2: Muscles
      Muscles make up the bulk of an animal’s body and account for about half its weight. The meat on the chop or roast is muscle and is composed mainly of protein. The cells that make up muscle tissue are elongated and able to contract to a half or even a third of their length when at rest. There are three different kinds of muscle based on appearance and function: smooth, cardiac and skeletal muscle.
    • 7.3: Smooth Muscle
      There are three different kinds of muscle tissue: smooth muscle in the walls of the gut and blood vessels; cardiac muscle in the heart and skeletal muscle attached to the skeleton.
    • 7.4: Cardiac Muscle

    Thumbnail: Superficial muscles of the chest, including pectoralis major (Public Domain; Gray's Anatomy).