Download THE MUSCULAR SYSTEM

THE MUSCULAR
SYSTEM
Module #6 – To Understand the Structure and Function of
Muscles
YOUR AMAZING MUSCULAR SYSTEM:
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You have about 650 muscles in your body.
There are over 150 just in your head and neck!
Your muscles make up 50% of your body weight.
Muscle tissue is three times more efficient at burning
calories than fat.
Your muscle cells produce enough heat every day to boil
almost 2 pints of water for an hour.
Your tireless heart beats more than 4500 times each hour.
Smile! You've just used about 30 muscles. Muscles control
your eyelids, nostrils and brow. They work together to show
the slightest change in your emotions.
MUSCLES ARE IMPORTANT BECAUSE
THEY…
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Hold your organs in place
Hold your bones together so
that you can move
Help you chew your food
Open and close your eyelids
Pump your blood
Allow you to move and
exercise
Enable you to have good
posture
TYPES OF MUSCLES
THE MAJOR
MUSCLES AND
ACTIONS
POSTURE
MUSCLES
TYPES OF
CONTRACTION
MUSCLE FIBER
TYPES
HOW MUSCLES
WORK
WHAT HAPPENS
DURING
EXERCISE
THE THREE TYPES OF MUSCLE
1. Cardiac Muscle (Heart)
2. Smooth or Involuntary Muscle
3. Skeletal/Striped or Voluntary Muscle
BASIC FEATURES OF A SKELETAL MUSCLE
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Muscle attachments
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Most skeletal muscles run
from one bone to another
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They are under our
conscious control
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We use them to run, jump,
walk
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One bone will move – other
bone remains fixed
 Origin – less movable
attachment
 Insertion – more
movable attachment
THE MAJOR SKELETAL MUSCLES
 Abdominals
(4)
 Quadriceps (4)
 Hamstrings (3)
 Gluteals (3)
 Pectorals
 Anterior Tibialis
 Gastrocnemius
 Lattissimus
 Trapezius
Deltoid
 Triceps
 Biceps
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Dorsi
MUSCLE
Deltoid
Biceps
Abdominals
Quadriceps
Pectorals
Latissimus Dorsi
Trapezius
Triceps
Gluteals
Hamstrings
Gastrocnemius
MAIN ACTION
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Anterior Tibialis
Raises your arm sideways at the shoulder
Bends your arm at the elbow
Pull in your abdomen, Flex your trunk so you can bend
forward.
Straighten your leg at the knee and keep it straight
when you stand
Raises your arm at the shoulder. Draws it across your
chest.
Pulls your arm down at the shoulder. Draws it behind
your back.
Holds and rotates your shoulders. Moves your head
back and sideways.
Straightens your arm at the elbow
Pulls your leg back at the hip. Raise it sideways at the
hip. Gluteus Maximus is the largest muscle in body.
Bend your leg at the knee
Straightens the ankle joint, so you can stand on your
toes.
Works opposite of the gastrocnemius to pull foot
towards knee
MUSCLES MUST WORK IN PAIRS:
Muscles can only contract: If one muscle
contracts to bring bones together, another
muscle must contract to bring the bones apart
(a bicep /tricep contraction, to bend the arm)
 We need large numbers of pairs of muscles to
work together in different ways for even simple
body movements.
 Our muscles take on different roles depending
on the movement they are to perform.
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ANTAGONISTIC MUSCLES: THEY WORK IN PAIRS
MUSCLE ATTACHMENTS: TENDONS ATTACH
MUSCLES TO BONE
SMOOTH OR INVOLUNTARY MUSCLES
These muscles work automatically – they are
not under our conscious control.
 They fatigue..but very slowly
 Found in the digestive system: stomach,
esophagus, intestines, control digestion
 Found in the respiratory system: lungs,
diaphragm, control breathing
 Found in urinary system: bladder, controls
urination
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CARDIAC MUSCLE
Cardiac is a special type of involuntary muscle
 It is only found in the heart
 It works automatically but under constant
nervous system and chemical control.
 Contractions of the heart muscle pump blood
throughout the body and account for the heart
beat
 Healthy cardiac muscle never fatigues or else…
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HOW DO OUR MUSCLES WORK?
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There are three main types of muscular contraction:
 Isotonic and concentric: muscles shorten as they contract,
the ends of the muscle move closer together (like in a
biceps during a pull up), most sport moves are this type of
contraction
 Isotonic and eccentric : muscles lengthen as they contract,
the ends move farther apart, (like the biceps when lowering
down from a pull up), plyometrics
 Isometric: muscles stay the same length when contracting,
there is no movement, (like your shoulders in a tug of war),
in sporting events the stabilizing muscles hold parts of the
body steady as other parts move
HOW ARE MUSCLES ATTACHED TO BONES?
Muscles are usually attached to 2 or more
different bones
 The muscle fibers end in s strong, white fibrous
cord called a tendon
 This anchors the tendon strongly and spreads
the force of the contraction
 Tendons attach muscle to bone
 Ligaments attach bone to bone
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MUSCLE FIBER TYPES:
There are two different types of muscle fibers:
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Slow Twitch: have a very good oxygen supply, work for a long
time without fatigue, are not as strong as fast twitch, take
longer to contract, are used in all types of exercise (especially
aerobic activities).
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Fast Twitch: do not have a good oxygen supply, tire
very quickly, are stronger than slow twitch, are used in
powerful, fast, movements, are used in high intensity exercise,
used in anaerobic activities
MIXTURE OF MUSCLE FIBERS:
Every muscle contains a mixture of fast and slow
twitch muscle fibers, but…
 The mixture is different in every muscle, for
example the gastrocnemius muscle contains a
lot of fast twitch fibers so standing on your toes
is tiring.
 The mixture is also unique to each individual.
Some distance runners have 80% slow twitch
while some power lifters have 80% fast twitch.
WHAT DOES THIS MEAN FOR SPORTS
PERFORMANCE?
The more fast twitch fibers you have the more
you are suited for sports requiring bursts of
strength and power.
 Consider two sprinters X and Y. They both are
the same age, weight and fitness level. X has
75% fast twitch fibers in his legs and Y only has
55%. Physiologically, X is suited better for
sprinting than Y.
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MUSCLE FIBERS AND SPORT
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If we jog slowly, only a few of our slow twitch fibers contract to
move our legs. When we increase our speed we use more slow
twitch fibers. As we run faster our fast twitch fibers also start
to contract to help out. More and more fibers will start to
contract as we run even faster. At our top speed all or our fast
twitch and slow twitch fibers will be working.
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Our muscle change based on activity:
Muscle hypertrophy – the muscle increases
in size with resistance training
Muscle atrophy – muscle decreases in size
(“Use it or lose it”) when it is not used
MUSCLE TONE:
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Even when a muscle is relaxed, a small number of fibers are
contracted – enough to keep the muscle taut but not enough to
cause movement.
This partial state of contraction is referred to as “muscle tone”.
Without muscle tone you would not be able to stand up
straight.
To maintain muscle tone without getting tired, groups of
muscles take turns in contracting. They
work in relays.
Poor muscle tone leads to poor posture.
Exercise improves muscle tone – it makes
the fibers thicker so they may contract
stronger.
WHAT HAPPENS TO OUR MUSCLES AS WE
EXERCISE?
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There is an increased flow of blood to the working muscles.
Muscles take up more oxygen from the blood.
The muscles contract more often and more quickly.
More of the muscle fibers contract
There is a rise in the temperature of the muscle
Waste products such as carbon dioxide and lactic acid build
up in the muscles, these products lead to tiredness and
cramps
Stores of muscle glucose are expended
Our ability to continue exercising may be affected
Overuse of muscles can lead to soreness, strains and stress
fractures.
QUESTIONS????
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How many muscles do you have in your body? (1 point)
List 4 different functions of your muscles. (2 points )
Explain the 3 types of muscles. A minimum of 4 sentences for each type.
(12 points)
List four major muscle groups and the action they create. (8 points)
Explain how muscles work in pairs. (2 points)
List and describe the 3 types of muscular contraction. Give an example of
each type of contraction (not the ones listed). (6 points)
Describe the two types of muscle fibers. What sports would be suitable for
each type? List at least three per type. (5 points)
How do muscles change based on activity? (2 points)
What is muscle tone? How does it affect us on a daily basis? (2 points)
List and explain 3 actions that occur when are muscles are being exercised.
(3 points)
43 points possible