1. Anatomy and Physiology of the Human Body11
Anatomy and Physiology of the Human Body

2. 6 The Muscular System U N I T
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3. Major Skeletal Muscles
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4. Skeletal Muscle Tissue
Attaches to bone to permit movement
Skeletal muscle movement is voluntary.
Skeletal muscle cells are long and strong and are arranged in bundles enclosed in tough connective tissue sheaths.
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5. Smooth Muscle Tissue
Small, delicate muscle cells found throughout the internal organs of the body
Smooth muscle activity is involuntary and occurs constantly in functions such as breathing, peristalsis, blood vessel contraction, and pupil dilation.
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6. Cardiac Muscle Tissue Muscle tissue found only in the heart
Arranged in a continuous network without sheath separation
When one cell receives the signal to contract, all neighboring cells are stimulated and they contract together.
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7. Six Functions of Skeletal Muscles
Contractions provide heat.
Contractions permit movement.
Hold the trunk and head erect
Protect blood vessels and nerves
Help blood flow return to the heart
Provide protective padding for internal organs
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8. Muscle Activity and Heat Production
Muscles use stored glycogen as an energy source.
As this fuel is used, heat is produced and warms the body.
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9. Muscle Teams When muscles contract they become shorter and thicker.
Skeletal muscles that bend joints are called flexors.
Skeletal muscles that straighten out a joint are called extensors.
(continued)
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10. Muscle Teams
When a flexor muscle is partnered with an extensor muscle they work as a team to bend and straighten joints.
The biceps and triceps of the upper arm are an example of a muscle team.
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11. Muscle Tone
Most skeletal muscles are partially contracted at all times so that the body remains erect.
This constant state of contraction is known as muscle tone.
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12. Muscle Sheaths and Bursae
Membranes that separate muscle groups to prevent friction from movement
Bursae
A sheath that is shaped like a sac and has a slippery fluid lining that acts as a cushion to minimize pressure and friction
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13. Peristalsis
Involuntary contraction of smooth muscle that results from alternate contraction and relaxation of the layers of the smooth muscle
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14. Sphincter Muscles
Smooth, donut-shaped muscles that pinch shut intermittently to control the flow of blood, food, or liquid
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15. Tendons and Ligaments Tendons Ligaments
Strong, fibrous connective tissue sheaths that do not bend or stretch
Tendons attach muscle to bone.
Ligaments
Flexible, fibrous tissue that supports organs
Tendons connect bones to bones at the joints.
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16. Diseases and Disorders
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17. Bursitis and Tendonitis
Painful inflammation of the bursae that cover and lubricate muscles and tendons
Tendonitis
Painful inflammation of the tendons and muscle attachments to the bone
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18. Fibromyalgia Syndrome
Chronic musculoskeletal condition that causes widespread pain and the presence of tender points or trigger points throughout the body
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19. Muscular Dystrophy
Group of congenital disorders that result in progressive wasting away of skeletal muscle and eventually death
Duchenne’s
Diagnosed usually by age 1; death occurs by age 10 to 15
Erb’s
Slow progression of atrophy that occurs later in childhood or adolescence
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20. Mixed Dystrophy Does not appear to be inherited Can affect both sexes
Usually begins between ages 30 and 50; death usually occurs within 5 years after onset
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21. Torticollis
Congenital or acquired neck deformity that bends the head toward the affected side
Caused by shortening or spasms of the sternocleidomastoid muscle
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22. Unit Summary
What are the characteristics of, and differences between, skeletal, smooth, and cardiac muscle?
What does the term flexor refers to?
How does food move through the body?
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