The Muscular SystemThe Muscular System

Support SystemsSupport SystemsUnit 2Unit 2

Functions of the Muscular SystemFunctions of the Muscular System• Heat Production (thermogenesis)

– Heat is a byproduct of muscle contraction

• Movement Facilitation– Muscles shorten and pull on bones

which produces movement• Structure (postural support)

– Contraction of muscles keeps us upright and maintains posture

Functions cont.Functions cont.• Protection of Internal Organs

– Contraction of abdominal muscles causes them to become hard and offers protection to the underlying organs

– Other muscles con contract prior to receiving a blow thus protection bones and soft tissue.

• Controls the volume of hollow organs– Smooth muscle surrounds our hollow organs and

contractions propel the substances through them, aid in their emptying, or helps control their volume

• Stomach and small intestines• The bladder• Blood vessels

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Cardiac Muscle

• Striated – appears striped under a microscope

• Involuntary- no conscious control

• Found in the heart

Smooth MuscleSmooth Muscle• Located in walls of

hollow internal surfaces such as:– blood vessels -

stomach– urinary bladder -

intestines• Non-striated in

appearance• Involuntary

Skeletal MuscleSkeletal Muscle• Attached to

bones• Striated

appearance under a microscope

• Voluntary control (conscious control)

Diseases and Diseases and Disorders of the Disorders of the

Muscular SystemMuscular System

TendonitisTendonitis• Characterized by

Inflammation of the tendons due to overuse or age-related changes of the tendon.

• Common in individuals who begin a new exercise or increase their level of exercise.

• Treatment includes: rest, ice, compression, and elevation (RICE).

StrainsStrains• A tearing of a muscle or

its attaching tendon • Occurs when a muscle

receives a stress that overcomes its strength– Sudden, quick heavy

lifting– During sports– While performing work

tasks

Strains cont.Strains cont.• 3 types of strains3 types of strains

– A 1A 1stst degree occurs when the muscle is stretched degree occurs when the muscle is stretched causing micro-tears in the muscle fiberscausing micro-tears in the muscle fibers

– A 2A 2ndnd degree strain occurs when the muscle or degree strain occurs when the muscle or tendon is partially torntendon is partially torn

– A 3A 3rdrd degree strain occurs when the muscle is degree strain occurs when the muscle is completely rupturedcompletely ruptured

• Signs & symptoms include:Signs & symptoms include:– Pain, especially when the muscle is contracting Pain, especially when the muscle is contracting

which limits functionwhich limits function– SwellingSwelling– BruisingBruising

• Treatment includes Rest, Ice, Compression, ElevationTreatment includes Rest, Ice, Compression, Elevation

Muscle SpasmMuscle Spasm• An involuntary muscle contraction• Also called a “Charlie Horse” or

“muscle cramp”• Main causes are electrolyte

imbalances, dehydration and fatigue

Muscle Spasm cont.Muscle Spasm cont.• Initial treatment is to put the muscle

that has the spasm on stretch– If spasm persists ice or heat can be

used• Prevention incudes maintaining a

proper diet, drinking plenty of water and proper conditioning– Sports drinks may be beneficial

during exercise to help replace lost sodium due to sweating

Muscular DystrophyMuscular Dystrophy• An inherited disorder in which

the muscles are missing a certain protein causing degeneration of muscle tissue

• Causes progressive weakness and loss of function of the affected muscles

• There is no cure but physical therapy can lessen the severity of the disorder.