© 2009 Delmar, Cengage Learning Chapter 7 Muscular System

© 2009 Delmar, Cengage Learning Functions of Muscular System Body heat to maintain body temperature Body movement Body form and shape to maintain posture

© 2009 Delmar, Cengage Learning Types of Muscles Skeletal muscle Smooth muscle Cardiac muscle

© 2009 Delmar, Cengage Learning Skeletal Muscle Under conscious control Attached to the bones of the skeleton Each muscle cell is known as a muscle fiber

© 2009 Delmar, Cengage Learning Smooth Muscle Not under conscious control Found in the walls of internal organs Controlled by the autonomic nervous system

© 2009 Delmar, Cengage Learning Cardiac Muscle In the heart only Not under conscious control Requires a continuous supply of oxygen to function

© 2009 Delmar, Cengage Learning Special Circular Muscles Sphincter or dilator muscles –Located in the openings between the esophagus and stomach, and the stomach and small intestine –Function is to control the passage of substances by opening and closing

© 2009 Delmar, Cengage Learning Summary of Muscle Tissue FeatureSkeletalSmooth (Visceral)Cardiac LocationAttached to bonesWalls of internal organs and blood vessels Heart FunctionProduce body movement Contraction of visceral and blood vessels Pump blood through heart and blood vessels Cell ShapeCylindricSpindle shaped, tapered ends Cylindric, branching Number of Nuclei ManyOne StriationsPresentAbsentPresent Type of ControlVoluntaryInvoluntary

© 2009 Delmar, Cengage Learning Characteristics of Muscles Contractibility Excitability or irritability Extensibility Elasticity

© 2009 Delmar, Cengage Learning Muscle Attachments and Functions Over 650 muscles in the body Muscles must be attached to bones for leverage Muscles only pull, never push Attached to bone by tendons Muscles are attached at both ends Attachments may be to bones, cartilage, ligaments, tendons, skin or to each other Origin and insertion Prime mover and antagonist Synergists

© 2009 Delmar, Cengage Learning Sources of Energy and Heat Narrow range of normal body temperature –98.6 °F to 99.8°F ATP (adenosine triphosphate) –Need oxygen, glucose, and other material to make –By-product is lactic acid

© 2009 Delmar, Cengage Learning Contraction of Skeletal Muscle Myoneural stimulation Contraction of muscle proteins

© 2009 Delmar, Cengage Learning

Principle Skeletal Muscles Skeletal or voluntary muscles –Move the skeleton Also control movement of the eyeballs, eyelids, lips, tongues, and skin

© 2009 Delmar, Cengage Learning Naming of Skeletal Muscles Location Size Direction Number of origins Location of origin and insertion Not all muscles are named by above method

© 2009 Delmar, Cengage Learning Muscles 656 muscles 327 antagonistic muscle pairs and two unpaired muscles –Orbicularis oris –Diaphragm Muscle regions –Head muscles –Neck muscles –Trunk and extremity muscles

© 2009 Delmar, Cengage Learning Muscles of the Head and Neck Control expressions Mastication Movement of the head

© 2009 Delmar, Cengage Learning

Muscles of the Upper Extremities Shoulder, arm and hand movements

© 2009 Delmar, Cengage Learning Muscles of the Trunk Breathing and movement of the abdomen and pelvis

© 2009 Delmar, Cengage Learning Muscles of the Lower Extremities Thigh, leg, ankle, foot, and toes