The Muscular System
Support Systems
Unit 2
Functions 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.
• 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
Anterior Skeletal Muscles
Posterior Skeletal Muscles
Cardiac Muscle
• Striated – appears striped
under a microscope
• Involuntary- no conscious
control
• Found in the heart
Smooth Muscle
• Located in walls of
hollow internal
surfaces such as:
– blood vessels
stomach
– urinary bladder
intestines
• Non-striated in
appearance
• Involuntary
-
-
Skeletal Muscle
• Attached to
bones
• Striated
appearance
under a
microscope
• Voluntary control
(conscious
control)
Diseases and
Disorders of the
Muscular System
Tendonitis
• 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).
Strains
• 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.
•
3 types of strains
– A 1st degree occurs when the muscle is stretched
causing micro-tears in the muscle fibers
– A 2nd degree strain occurs when the muscle or
tendon is partially torn
– A 3rd degree strain occurs when the muscle is
completely ruptured
•
Signs & symptoms include:
– Pain, especially when the muscle is contracting
which limits function
– Swelling
– Bruising
•
Treatment includes Rest, Ice, Compression,
Elevation
Muscle Spasm
• An involuntary muscle contraction
• Also called a “Charlie Horse” or
“muscle cramp”
• Main causes are electrolyte
imbalances, dehydration and
fatigue
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 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.