1. CHAPTER 15 Muscles of the Body

2. Sports & Injury

3. 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

4. skeletal
cardiac
smooth

5. Unique Characteristics of Muscle
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

6. 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

7. Figure 15-3 Parts of a Muscle

8. Figure 15-4 Types of Muscle Movement
SYSTEM

9. Smooth Muscle/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 (not under your control)

10. Cardiac Muscle Found only in the heart Striated muscle
Under involuntary control
Has specialized cells that provide a stimulus for contraction

11. 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

12. 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 (

13. Assessment Techniques
Joint ROM
Measure using a goniometer
Blood tests
CPK isoenzyme test measures creatine phosphokinase (CPK) in the blood. CPK found in the heart, brain, and skeletal muscles.
Measure lactic acid
Electromyography tests
Tests muscles through needles
inserted into the muscle
Muscle biopsy
Used to assess for tissue disorders
Muscular dystrophy, polio, necrotizing disease

14. Disorders Back pain Contracture
From weakened muscles around the spine in the lower back
Contracture
When muscles remain contracted as a joint loses flexibility and ligaments and tendons shorten
When your muscles move less, they shrink and shorten.

15. Disorders of the Muscular System
Muscular dystrophy
A group of genetic diseases
involving painless, gradual atrophy
of muscle tissue

16. Disorders of the Muscular System
Gangrene
Caused by Clostridium bacteria that kill muscle tissue
Poliomyelitis (Polio)
A viral infection that results in paralysis of muscles

17. Disorders of the Muscular System
Hernia
The abnormal protrusion of a body part into another body area

18. Disorders of the Muscular System
Trichinosis
A parasitic infection caused by eating undercooked pork or other meats

19. 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

20. Disorders of the Muscular System
Muscle sprain
A traumatic injury to the between two bones in a joint
Most common is an ankle sprain
Ligamentous Pull
Muscle strain
Torn or stretched tendons and muscles, causing pain

21. Pes planus: Called “flatfoot” or “fallen arches,” may be congenital or result from weakened foot muscles
Pes Planus: over-pronation
High Arches: Supination

22. Muscular/Skeletal Careers
Physical Therapy
Occupational Therapy
Orthopedic Surgery
Athletic Trainer

23. Lab Activity: ROM & Goniometer
ROM
Goniometer
Infant Reflexes
Reflex Hammer