Download Muscular system

Structure and
Movement
The Muscular System
The Muscular System
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A. A muscle is an
organ that can
relax and contract,
and provides the
force to move your
body parts.
Muscular system
is composed of
over 600 muscles
Characteristics of muscles
Excitability: Tissue can receive & respond to
stimulation
 Contractility: Tissue can shorten & thicken
 Extensibility: Tissue can lengthen
 Elasticity: After contracting or lengthening, tissue
always wants to return to its resting state
 Muscles always pull, never push
 Blood carries energy-rich molecules to the muscles
so they can do their work.
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Functions of the Muscular system
There are four functions of the muscular
system they are:
-Produce movement
-Maintain posture and body position
-Support soft tissue and protect joints
-Maintain body temperature/keep body warm
Voluntary vs. Involuntary
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Voluntary
muscles –
muscles that you
are able to
control
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Involuntary
muscles – muscles
that you cannot
control
Slow-twitch vs. Fast-twitch
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Slow-twitch muscle
fibers
Take three times longer
to contract; however,
they can continue
contracting for
extended periods after
a fast muscle would
have become fatigued.
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Fast-twitch muscle fibers
Most of the skeletal
muscle fibers in the body
are fast fibers because
they can contract in 0.10
seconds or less following
stimulation.
Aerobic Exercise vs. Anaerobic
Anaerobic
Exercise that is explosive in
power and speed, over a
short period of time and is
“without oxygen”
Examples:
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Aerobic
Exercise that is done at
moderate intensity,
extended over a period of
time, and are done “with
oxygen”
Examples:
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Soccer
Basketball
Lacrosse
Endurance running (cross
country)
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Weight Lifting
Volleyball
Football
Baseball (Softball)
The Muscular System
There are 3 types of muscle tissue
 1. Skeletal muscle moves bones
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-Most common type of muscle
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-Voluntary muscles
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-Contract quickly and tire more easily
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-Look striped, or striated
The Muscular System
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2. Smooth muscles – found in the internal organs
a. Example: intestines
b. Smooth muscles are involuntary muscles
c.Contract and relax slowly
The Muscular System
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3. Cardiac muscle
a. Found only in the heart
b.Cardiac muscle is striated, like skeletal muscle
Involuntary
Project
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Trifold pamphlet
Front page: Muscle tissue found in the body
Inside 3 pages: One muscle tissue per page
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For each one name: What does it do, Where is it
found, voluntary or involuntary, sketch what it looks
like
Last page, draw an example of each
The Muscular System
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A. You move
because pairs of
muscles work
together.
1. When one
muscle of a pair
contracts, the other
relaxes.
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Example- Bicep/Tricep or
Hamstring/Quadricep
Biceps contract together
(flex) and the triceps
extend (relaxes)
Atrophy vs Hypertrophy
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Atrophy
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Decrease or wasting away
of muscle tissue
Can happen when body
part is injured and the
athlete can not use
Must try to prevent if
possible. If not possible,
then conditioning will be a
priority when the injury
has healed
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Hypertrophy
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Excessive growth of
muscle tissue.
The muscle will adapt to
excess stress (working
out) and get bigger.
Attachment
-Skeletal muscles are
usually long and narrow,
span a joint, and are
attached to a bone at
either end by a tendon.
-A tendon is toughened,
dense fibrous connective
tissue that connects a
muscle to the periosteum
of a bone.
Attachment
-As the muscle contracts it shortens. One of
the bones moves relative to the other joint.
-The more fixed, or stationary, attachment is
designated as the origin of a muscle,
whereas the movable end is its insertion.
Muscle Fatigue
-A skeletal muscle fiber is said to be fatigued
when it can no longer contract despite
continued neural stimulation.
-Muscle fatigue is caused by the exhaustion
of energy reserves or builds up of lactic
acid
Affects of muscle fatigue
Affects of muscle fatigue
Affects of muscle fatigue
Muscle Fatigue experiment
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Volunteers?
We are going to test how different muscles may fatigue
faster than others.
We will also test how your pulse rises.
1st… get your resting pulse
2nd…Hold a book out in front of you with both hands.
Hold it as long as you can.
3rd… Time how long each person can hold out the book
4th…get your recovery pulse
Why were some people able to hold the book up longer
than others?
Why did their pulse increase if they were not moving?
Lactic Acid
Lactic acid- body waste product found in muscles and
tissues
When a muscle produces a sudden, intense burst of activity
(anaerobic exercises), there is insufficient oxygen
available for the body. Pyruvic acid (product created in
the body during the metabolism of carbohydrates and
protein) is broken down creating lactic acid.
After a relatively short time (seconds to minutes) the rising
lactic acids levels lower the tissue pH and the muscle can
no longer function normally.
Athletes running sprints have this type of fatigue
(anaerobic exercises)
Lactic Acid
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When muscle
contraction is strenuous,
oxygen supply cannot
keep up with the demand
so body uses reactions
that generate lactic acid
so that more ATP can be
made to continue with
muscle contraction
Lactic Acid
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Physically fit people
make less lactic acid
because strenuous
activity causes new
capillary growth
supplying an increased
amount of oxygen and
nutrients; also extra
mitochondria are made
which can make more
ATP
Lactic Acid
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The process of lactic acid removal takes
approximately one hour, but this can be
accelerated by undertaking an appropriate cool
down that ensures a rapid and continuous
supply of oxygen to the muscles.
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Drink plenty of water
Muscle Cramps
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Lactic acid causes fatigue and muscle cramps
Aging and the muscular system
Skeletal muscles become smaller in diameter.
Skeletal muscles become less elastic.
The tolerance for exercise decreases.
The ability to recover from muscular injuries
decrease.
Aging and the muscular system
Anatomy of skeletal muscles
epimysium
tendon
perimysium
Muscle
Fascicle
Surrounded by
perimysium
Skeletal
muscle
Surrounded by
epimysium
endomysium
Skeletal
muscle
fiber (cell)
Surrounded by
endomysium
Play IP Anatomy of Skeletal muscles (IP p. 4-6)
Dissection of a skeletal muscle
Different muscle tissues
Skeletal muscle
Cardiac muscle
Smooth muscle
Injuries to the muscular system
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Muscle Strain- An overstretching or tearing of
the muscles and/or the adjacent tissues such as
the tendon. (pulled muscle)
Most muscle strains occur where the muscle and
tendon meet.
 They most commonly affect the hamstring or
quadriceps group
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Tendonitis- Inflammation of a tendon
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Caused by excessive or unusual use
Types of muscle strains
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Mild strains (1st degree)
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Moderate strains (2nd degree)
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Mild tearing of the muscle, mild pain with stretching and
contraction, mild loss of function and ROM, possible muscle
spasms
More painful that 1st degree when contracted and stretched, a
snap or tearing sound is sometimes heard by athlete, point
tenderness, moderate swelling, moderate to severe loss of
function and ROM, and possible muscle spasms
Severe strain (3rd degree)
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Rupture of the tendon or muscle tissue, decrease or increase
ROM, severe loss of function, defect in the muscle that is
palpable, and possible muscle spasms
Muscle Strain Treatment
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Ice the area as soon as symptoms develop, using
the ICE procedure
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Ice, Compression, Elevation
In severe cases, immobilizing the injured area is
also recommended
Prevention: teach your athletes strengthening
and flexibility exercises for the areas of the body
that are vulnerable to injury