CHAPTER 15 MUSCULAR SYSTEM Antagonist Atrophy Contraction Contracture Dystrophy Myalgia Paralysis Posture Prime mover Range of motion Sarcomere Skeletal Stimulus Tonus Visceral Journal question: What are the six functions of the muscular system?

Chapter 15 Learning Objectives Define at least 10 terms relating to the muscular system. Describe the six functions of the muscular system. Identify at least 10 structures of the muscular system, and explain the function of each.

Chapter 15 Learning Objectives Describe at least three methods of assessment of the muscular system. Describe at least five disorders of the muscular system.

Structure and Function Functions of the muscular system Aid in movement Provide and maintain posture Protect internal organs Provide movement of blood, food, and waste products through the body Open and close body openings Produce heat The human body has more than 600 muscles.

Common Muscle Groups The human body has fewer muscles in it than a caterpillar. FIGURE 15-2 Common muscle groups. A, Front view. (From Sorrentino S: Mosby’s textbook for nursing assistants, ed 7, St. Louis, 2008, Mosby.)

Common Muscle Groups FIGURE 15-2 Common muscle groups. B, Back view. (From Sorrentino S: Mosby’s textbook for nursing assistants, ed 7, St. Louis, 2008, Mosby.)

Types of Muscle Tissue Discuss the three types of muscle tissue and where they are located in the body.

Unique Characteristics of Muscle Tissue Irritability or excitability Muscle’s ability to respond to a stimulus Contractility Ability to shorten forcefully when stimulated Extensibility Ability to stretch and lengthen Elasticity Ability to recoil to its resting length when relaxed Discuss the difference between the irritability and excitability characteristics of muscle tissue.

Skeletal Muscle Makes up more than 40% of a person’s body weight Looks striated, or banded, under the microscope Skeletal muscles have three parts: Origin is one end of the muscle, attached to the less movable part of the bone. Insertion is the other end of the muscle, attached to the more movable part of the bone. The action, or body, is the thick middle part of the muscle. Skeletal muscles are also called voluntary or striated muscles. Discuss locations of skeletal muscles in the human body.

Parts Of A Muscle Review the origin, action, and insertion parts of a muscle. FIGURE 15-4 Parts of a muscle.

Skeletal Muscle Movement Working in pairs, have students mimic skeletal muscle movement, as in the Figure 15-5, and feel a contracted and relaxed muscle movement. FIGURE 15-5 Skeletal muscle movement.

Types of Muscle Movement Call on several students to demonstrate the four types of muscle movement in Figure 15-6, one at a time. Have the class identify what muscle movement the student is demonstrating, using the correct term for each. FIGURE 15-6 Types of muscle movement. A, Flexion and extension. B, Rotation. C, Abduction and adduction. D, Pronation and supination.

Visceral Muscle Lines various hollow organs Makes up the walls of blood vessels Found in the tubes of the digestive system Smooth and has no striations Controlled by the autonomic nervous system Visceral muscles are also called involuntary muscles or smooth muscles.

Cardiac Muscle Found only in the heart Striated muscle Under involuntary control Has specialized cells that provide a stimulus for contraction The cardiac muscle makes up most of the heart.

Muscle Contraction Isotonic contraction is muscle shortening that produces movement. Muscle tone, or tonus, is a state of partial contraction that maintains a person’s posture. Isometric contraction does not cause muscle shortening or movement. A twitch is a quick, jerky contraction of a whole muscle from one stimulus. Not all muscle contractions are the same. The eye has the fasting reacting muscle in the whole body. It contracts in 1/100th of a second.

Muscle Contraction Tetanic contraction is more sustained than a twitch. Fibrillation is uncoordinated contraction of muscle fibers. Convulsions are contractions of groups of muscles in an abnormal manner. Spasms are involuntary, sudden, and prolonged contractions. Tetanic contraction is caused by many stimuli in rapid succession.

Assessment Techniques Reflex tests Assesses neurologic functioning Joint motion measured using a protractor Range of joint motion Blood tests Measures enzymes Electromyography Tests muscles through needles inserted into the muscle Muscle biopsy Used to assess for tissue disorders The muscular system is assessed for asymmetry, deformity, swelling, or bruising with general inspection. With systematic movement of the body parts, muscle groups can be assessed for weakness.

Disorders of the Muscular System Back pain From weakened muscles around the spine in the lower back Contracture Condition in which muscles remain contracted as a joint loses flexibility and ligaments and tendons shorten Viral infection that results in paralysis of muscles Muscle cramp Sudden involuntary contraction of a muscle, producing pain Discuss the causes, symptoms, and treatment of these disorders.

Disorders of the Muscular System Muscular dystrophy Group of genetic diseases involving painless, gradual atrophy of muscle tissue Fibromyalgia Group of muscle disorders affecting the tendons, ligaments, and other fibrous tissues Gangrene Caused by Clostridium bacteria that kill muscle tissue Discuss the causes, symptoms, and treatment of these disorders.

Disorders of the Muscular System Hernia Abnormal protrusion of a body part into another body area Myasthenia gravis Condition in which nerve impulses are not transmitted normally from the brain to the muscles Poliomyelitis Discuss the causes, symptoms, and treatment of these disorders.

Disorders of the Muscular System Muscle sprain Traumatic injury to the tendons, muscles, or ligaments of a joint Muscle strain Torn or stretched tendons and muscles, causing pain Pes planus Also called flatfoot or fallen arches, may be congenital or result from weakened foot muscles Discuss the causes, symptoms, and treatment of these disorders. Discuss possible preventions.

Disorders of the Muscular System Tetanus Commonly called lockjaw, is caused by a bacterial infection Trichinosis Parasitic infection caused by eating undercooked pork Discuss the symptoms, prevention, and treatment of these disorders.

Issues and Innovations Sports medicine Treats sports injuries Directs healthful development and training of athletes Addresses biomechanics Offers novel treatments Ultrasound Electric stimulation Platelet-rich plasma (PRP) therapy Ask student to name types of athletic injuries affecting the muscular system, such as strains, sprains, and bruises. Discuss the term biomechanics.

Issues and Innovations Fitness fads Importance of regular exercise for good health Feeling better Having less stress Exercise obsession Increase in number of health clubs and spas Dependence on “high” of exercise Endorphins are released while exercising. Person addicted to exercise feels withdrawal symptoms. According to the CDC, more than 20% of the population of all states (except Colorado) is obese.

Summary Functions of the muscular system Movement Posture Protection of internal organs Transport of blood Producing heat

Summary Structures of the muscular system Skeletal muscles Biceps Triceps Quadriceps Deltoid Masseter Gracilis Visceral muscle Cardiac muscle

Summary Methods of assessment of the muscular system Inspection Electromyography Blood and reflex tests

Summary Disorders of the muscular system Contractures Cramps Dystrophy Poliomyelitis Gangrene

Review Fibromyositis, with regard to the muscular system, is: a. Faulty growth b. Uncontrolled muscle contraction of the eyelid c. Inflammation of the muscle tissues d. A tumor of the muscle e. Interior organs

Review Fibromyositis, with regard to the muscular system, is: a. Faulty growth b. Uncontrolled muscle contraction of the eyelid c. Inflammation of the muscle tissues d. A tumor of the muscle e. Interior organs

Review The human body has more than: a. 400 muscles b. 450 muscles c. 500 muscles d. 550 muscles e. 600 muscles

Review The human body has more than: a. 400 muscles b. 450 muscles c. 500 muscles d. 550 muscles e. 600 muscles