copyright 2003 by mosby, inc. all rights reserved. chapter 14 muscular system

Copyright 2003 by Mosby, Inc. All rights reserved.

CHAPTER 14

MUSCULAR SYSTEM


Structure and Function

• The human body has more than 600 muscles

• The 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


Table 14-1 Types 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


Figure 14-5 Basic Types of Muscle Movement


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


Cardiac Muscle

• Found only in the heart• Striated muscle • Under involuntary control• Has specialized cells that provide a

stimulus for contraction


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


Muscle Contraction (continued)

• Tetanic contraction is more sustained than a twitch and is caused by many stimuli in rapid succession

• 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


Figure 14-8 Sliding Filament Theory


Assessment Techniques

• Reflex tests• Joint motion measured using a

protractor• Blood tests• Electromyography tests• Muscle biopsy


Disorders of the Muscular System • Back pain

– From weakened muscles around the spine in the lower back

• Contracture– A condition in which muscles remain

contracted as a joint loses flexibility and ligaments and tendons shorten

• Muscle cramp – A sudden involuntary contraction of a

muscle producing pain


Disorders of the Muscular System (continued)

• Muscular dystrophy– A group of genetic diseases involving

painless, gradual atrophy of muscle tissue

• Fibromyalgia – A group of muscle disorders affecting the

tendons, ligaments, and other fibrous tissues

• Gangrene– Caused by Clostridium bacteria that kill

muscle tissue



• Hernia – The abnormal protrusion of a body part into

another body area

• Myasthenia gravis– A condition in which nerve impulses are not

transmitted normally from the brain to the muscles

• Poliomyelitis – A viral infection that results in paralysis of

muscles



• Muscle sprain – A traumatic injury to the tendons, muscles, or

ligaments of a joint

• Muscle strain– Torn or stretched tendons and muscles,

causing pain

• Pes planus– Called “flatfoot” or “fallen arches,” may be

congenital or result from weakened foot muscles



• Tetanus– Commonly called “lockjaw,” is caused by a

bacterial infection

• Trichinosis – A parasitic infection caused by eating

undercooked pork


Issues and Innovations • Sports medicine

– Treating sports injuries

– Directing healthful development and training of athletes– Biomechanics

• Fitness fad– Importance of regular exercise for good health– Exercise obsession

copyright 2003 by mosby, inc. all rights reserved. chapter 14 muscular system

Documents

muscle slide

contraction slide

cardiac muscle

types of muscle tissue

movement muscle tone

group of muscle disorders

heart striated muscle

muscular system slide