Download document 6494825

Muscular System
By: Mr. Hill
Health 9
Woodbury Jr/Sr High School
Introduction
• 1. 600 muscles in the body
• 2. Muscles are ~ made of
bundles of muscle fibers
which are held together by
connective tissue.
• 3. When muscle fibers are
stimulated by nerves ~they
contract or become short and
thick.
• Voluntary ~ you can willfully
control muscles
*facial expressions,
chewing, swallowing, and
movement of the head
• Involuntary ~ function
without the person thinking
about contracting the
muscles.
*digestive system, heart
muscles, and blood vessels
**Some muscles are both
voluntary and involuntary ~
example eye blinking
THREE TYPES OF
MUSCLES
• 1. Cardiac muscles ~ cells
are packed so closely
together its hard to tell one
cell from another.
~forms walls of the heart
~contact to circulate blood
~involuntary
• 2. Visceral/Smooth muscles
~found in internal organs of the
body
*digestive, respiratory system,
blood vessels, and eyes.
~muscles contract to cause
movement in these areas
~involuntary function without
the person thinking about
contracting the muscle
• 3. Skeletal~ most abundant
muscle
~attached to bone
~causes body to move
~voluntary
FUNCTIONS OF SKELETAL
MUSCLES
• 1. Attaches to bones to
provide voluntary movement.
• 2. During contractions
provide heat and energy.
• 3. Helps maintain posture.
• 4. Some protect internal
organs.
SKELETAL MUSCLES
ATTACH TO BONES
IN
VARIOUS WAYS
• 1.Tendon ~ strong, tough
connective tissue cord, connect
muscle to bone
*Achilles Tendon (attaches
to calf muscle and heel bone)
*lumbodorsal
fascia (surrounds the deep
muscles of the back and trunk)
• 2. Fascia ~ tough, sheet-like
membrane that covers and
protects tissue
*lumbodorsal fascia
(surrounds the deep muscles
of the back and trunk)
• 3.Origin ~ When a muscle
attaches to the bone, the end
doesn’t move.
-usually attaches closer to
the trunk of the body
-where the muscle begins
• 4. Insertion ~ the end of the
muscle that attaches to a bone
that moves
where the muscle ends
CHARACTERISTICS
OF
MUSCLE TISSUES
1. Contractability ~ ability to
shorten and thicken (when
muscles work they contract
that is they get shorter
and thicker)
• 2. Extensibility ~ ability to
stretch (when muscle is
relaxed it becomes longer
and thinner)
*some muscles work while
others relax *
• 3.Elasticity ~ ability to return
to original length
• 4. Irritability ~ability to
respond to stimulus
• 5. Tone ~ slight tension in
the muscles at all times, even
at rest
MOVEMENT
PERFORMED
BY
MUSCLES
• 1. Adduction ~ moving a
body part toward the midline
• 2. Abduction ~ moving a
body part away from the
midline
• 3.Flexion (Flexor) ~
decreasing the angle between
two bones and body part
• 4. Extension ( Extensor) ~
increasing the angle between
two bones and body part
• 5. Rotation ~a circular
motion which turns a body
part on its axis
• 6. Sphincters: ring like
muscles that close body
openings
–example: rectum
• 7. Levators: lift a part of the
body
• 8. Depressors: lower a part of
the body
• 9. Supination: the act of
rotating the arm so the palm
of the hand is upward.
• 10. Pronation: the act of
rotating the arm so the palm
of the hand is turned
downward.
Terminology
• Muscle tone: muscles that
are partially contracted at all
times, even when they may
not be in use.
• Contracture: severe
tightening of a flexor muscle
that results in bending of a
joint.
• Myology: my/o = muscles
ology = study of
– the study of muscles
»
MYOLOGY
The Study of Muscles
CHARTS