Download Muscular System

The Muscular System
Functions of the Muscular
System
The muscles in your body are always at work
 Muscle make you breath, make your heart beat,
and help you move food through the digestive
system
 These involuntary processes happen without you
controlling them
 When you throw a ball or run in a game you are
using muscles that are under voluntary control
 Without the use of muscles you would be unable
to perform any of these tasks
Structure of Muscles
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Muscles are made of long cells called fibers
Major muscles are made of bundles of these fibers
Muscles work by to complementary, or opposing
actions.
These are Contractions – the shortening of a
muscle
Extension – the stretching of the muscle
Muscle contraction is triggered by nerve impulses
Types of Muscles

The body contains 3 types of muscles
– Smooth Muscle
– Skeletal Muscle
– Cardiac Muscle
Smooth Muscles

Act on the lining of
passageways and
internal organs
 Examples: Lining of
blood vessels, the
digestive tract, lungs,
and the bladder.
 Smooth muscles are
under involuntary
control
Skeletal Muscles

Are attached to bone and
cause body movement
 Skeletal muscles are
voluntary muscles
 Skeletal muscle has a
striated or striped
appearance
 Skeletal muscles work
together in pairs
– Flexors – muscle that closes
a joint
– Extensors – muscles that
open a joint
Cardiac Muscle
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Type of striated muscle
that form the walls of the
heart
This involuntary muscle is
responsible for the
contractions of the heart
The heart beats about
100,000 times a day to
pump blood through the
body
Muscular Terms
Atrophy – decrease in muscle size and strength.
Caused by long periods of physical inactivity
 Muscle Tone – the natural tension in the fibers of
a muscle
 Physical Activity helps keeps muscles strong,
healthy, and toned
 Practicing good posture strengthens back muscles

Muscles of the Skull

Frontalis(forehead)
 Temporalis(Side of
head)
 Masseter(jaw)
 Orbicularis oris(eye)
Muscles of the Trunk(Anterior)

Pectoralis
Major(Chest)
 Obliques(side of
stomach)
 Abdomen(Stomach)
Muscles of the
Trunk(Posterior)

Trapezius
 Rhomboid
 Latissimus dorsi
Muscles of the Arm

Deltoid(shoulder)
 Bicep(flexor)
 Tricep(extensor)
Muscles of the Leg
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Gluteus Maximus(hip
extensor)
Quadriceps(leg
extensor)
Hamstrings(leg flexor)
Gastrocnemius(foot
extensor)
Tibialis Anterior(foot
flexor)
Problems of the Muscular
System
Bruise – an area of discolored skin that appears
after an injury causes the blood vessels beneath
the skin to rupture and leak
 Muscle Strain – this is when a muscle is stretched
or partially torn as a result of overexertion.
 Tendonitis – inflammation of a tendon, caused by
injury, overuse, or natural aging. Includes joint
pain and swelling that worsens with activity
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Problems with the Muscular
System
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Hernia – when an organ
or tissue protrudes through
an area of weak muscle.
Results from straining to
lift a heavy object
Muscular Dystrophy –
inherited disorder in
which muscles are
progressively destroyed.
There is no cure, exercise
can slow the process.