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    The Muscular System: AIM: To Understand The Structure and Function of Muscles

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    puhi
    This document provides an overview of the muscular system, including the main types of muscles (skeletal, smooth, and cardiac), their structure and functions. It describes the major skeletal muscles and their actions. It explains how muscles contract through different types of contractions (isotonic, eccentric, isometric) and work antagonistically in pairs or groups. The document also discusses muscle fiber types, their roles in strength and endurance, and how they adapt to exercise.

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    The Muscular System: AIM: To Understand The Structure and Function of Muscles

    Uploaded by

    puhi
    188 views28 pages
    This document provides an overview of the muscular system, including the main types of muscles (skeletal, smooth, and cardiac), their structure and functions. It describes the major skeletal muscles and their actions. It explains how muscles contract through different types of contractions (isotonic, eccentric, isometric) and work antagonistically in pairs or groups. The document also discusses muscle fiber types, their roles in strength and endurance, and how they adapt to exercise.

    Original Description:

    muskujt

    Original Title

    sistemi muskular

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    This document provides an overview of the muscular system, including the main types of muscles (skeletal, smooth, and cardiac), their structure and functions. It describes the major skeletal muscles and their actions. It explains how muscles contract through different types of contractions (isotonic, eccentric, isometric) and work antagonistically in pairs or groups. The document also discusses muscle fiber types, their roles in strength and endurance, and how they adapt to exercise.

    Copyright:

    © All Rights Reserved
    Download as PPT, PDF, TXT or read online from Scribd
    Download as ppt, pdf, or txt
    188 views28 pages

    The Muscular System: AIM: To Understand The Structure and Function of Muscles

    Uploaded by

    puhi
    This document provides an overview of the muscular system, including the main types of muscles (skeletal, smooth, and cardiac), their structure and functions. It describes the major skeletal muscles and their actions. It explains how muscles contract through different types of contractions (isotonic, eccentric, isometric) and work antagonistically in pairs or groups. The document also discusses muscle fiber types, their roles in strength and endurance, and how they adapt to exercise.

    Copyright:

    © All Rights Reserved
    Download as PPT, PDF, TXT or read online from Scribd
    Download as ppt, pdf, or txt
    of 28

    THE MUSCULAR SYSTEM

    AIM: To understand the


    structure and
    function of
    muscles.

    WHAT I NEED TO KNOW


    Types of
    Muscles
    The Major
    Muscles and
    actions

    Posture

    MUSCLES
    Types of
    Contraction

    How Muscles
    Work

    Muscle Fibre
    Types

    What Happens
    When we
    Exercise

    WHAT DO OUR MUSCLES DO?


    OUR MUSCLES:

    Enable us to move our body parts.


    Give us our individual shape.
    Protect and keep in place our abdominal organs.
    Enable us to maintain good posture.
    Help in the circulation of our blood.
    Generate body heat when they contract .

    THERE ARE OVER 600 SKELETAL MUSCLES


    IN THE BODY- 150 IN THE HEAD AND NECK.

    TYPES OF MUSCLE
    We can put muscles into 3 types based on
    how they work:

    Skeletal/Striped or Voluntary Muscle

    Smooth or Involuntary Muscles.

    Cardiac Muscle

    SKELETAL or VOLUNTARY MUSCLES


    They are under our conscious control.
    This means we instruct them to
    perform everyday actions such
    as walking, running and jumping.
    How many can you name?

    THE MAJOR SKELETAL MUSCLES


    Deltoid
    Biceps
    Abdominals
    ( 4 muscles)
    Quadriceps
    (4 muscles)
    Pectorals

    Latissimus dorsi
    Trapezius
    Triceps
    Gluteals (3 muscles)
    Hamstrings (3
    muscles)
    Gastrocnemius

    MUSCLE

    MAIN ACTION(S)

    Deltoid

    Raises your arm sideways at the shoulder

    Biceps

    Bends your arm at the elbow

    Abdominals

    Pull in your abdomen. Flex your trunk so you can bend


    forward

    Quadriceps

    Straighten your leg at the knee and keep it straight when


    you stand

    Pectorals

    Raises your arm at the shoulder. Draws it across your


    chest

    Latissimus dorsi

    Pulls your arm down at the shoulder. Draws it behind your


    back

    Trapezius

    Holds and rotates your shoulders. Moves your head back


    and sideways

    Triceps

    Straightens your arm at the elbow

    Gluteals

    Pull your leg back at the hip. Raise it sideways at the hip.
    Gluteus maximus is the biggest

    Hamstrings

    Bend your leg at the knee

    gastrocnemius

    Straightens the ankle joint so you can stand on tiptoes

    SMOOTH or INVOLUNTARY MUSCLES


    These muscles work automatically they are not under
    our conscious control.
    e.g. Muscles of the digestive system.
    Can you think of any more?

    CARDIAC MUSCLE
    Cardiac is a special type of involuntary
    Muscle.
    It is ONLY found in the heart.
    It contracts regularly, continuously
    and without tiring.
    It works automatically but is
    under constant nervous and
    chemical control.

    HOW DO OUR MUSCLES WORK?


    There are 3 main types of muscular contraction:

    Isotonic and concentric

    Isotonic and eccentric

    Isometric

    ISOTONIC and CONCENTRIC


    Our muscles shorten as they contract.
    The ends of the muscle move
    closer together.
    e.g. the biceps during a pull-up
    Most sporting movements
    are of this type.

    ISOTONIC and ECCENTRIC


    Our muscles lengthen as they
    contract under tension.
    The ends of the muscle move
    further apart.
    e.g. the biceps when we
    lower down from
    a pull-up.
    Plyometric exercise uses
    eccentric contractions.

    ISOMETRIC
    Our muscles stay the same length as they
    contract.
    There is no movement, so the
    ends of the muscles stay the
    same distance apart.
    e.g. our shoulder muscles during
    a tug of war.
    In many sporting movements the stabilising
    muscles hold parts of the body steady as
    other parts move.

    HOW DO MUSCLES WORK TOGETHER?


    Muscles can only contract. If one muscle contracts to
    bring two bones together another muscle is need to
    Contract to bring the bones apart again.
    e.g. a bicep curl
    So, MUSCLES

    ALWAYS WORK IN PAIRS

    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 performing.

    MUSCLES CAN WORK AS:


    Flexors contracting to bend our joints.
    Extensors contracting to straighten joints.
    Prime movers (agonists) contracting to start
    a movement.
    Antagonists relaxing to allow movement to
    take place.
    Fixators contracting to give the working
    muscles a firm base.
    Synergists stabilising the area around the
    prime mover and fine tuning our movement.

    HOW ARE MUSCLES ATTACHED TO BONES?


    Muscles are usually attached to 2 or more different bones.
    The muscle fibres end in a strong, white flexible cord,
    called a TENDON. At the bone, the fibres of the tendon
    are embedded in the PERIOSTIUM
    of the bone. This anchors
    the tendon strongly and
    spreads the force of the
    Contraction
    REMEMBER:
    Tendons join muscle to bone.
    Ligaments join bone to bone.

    MUSCLE SPEED and TONE


    Muscle Fibres
    Our muscles are made up cells
    called muscle fibres. These tiny
    threadlike fibres are packed
    together in bundles. Muscles
    contract (shorten) because the
    fibres do.
    Muscle fibres dont all contract together. The number
    contracting at any one time depends on how much force
    is needed

    MUSCLE FIBRE TYPES


    We have two different types of fibres in skeletal
    muscle:
    SLOW-TWITCH

    FAST-TWITCH

    FAST-TWITCH MUSCLE FIBRES


    Do not have a good oxygen supply.
    Tire very quickly.
    Are stronger than slow-twitch fibres.
    Contract very quickly.
    Are used when we need fast, powerful
    movements.
    Are used only in high intensity exercise.
    Are used in anaerobic activities.

    Can you think of sports that use fast-twitch


    Fibres?

    SLOW-TWITCH MUSCLE FIBRES

    Have a very good oxygen supply.


    Work for a long time without tiring.
    Are not as strong as fast-twitch fibres
    Take longer to contract.
    Are used in all types of exercise.
    Are used especially in aerobic activities.

    Can you think of sports that use slow-twitch


    Fibres?

    MIXTURE OF MUSCLE FIBRES


    Every muscle contains a mixture of fast
    and slow twitch muscle fibres. BUT:
    The mixture is different in different muscles
    e.g. the gastrocnemius contains a lot of fast
    twitch fibres so standing on your toes is tiring
    The mixture is different for different
    people. Some distance runners have 80% slow
    twitch fibres while some power lifters have
    80% fast twitch

    MUSCLE SPEED and PERFORMANCE


    The more fast twitch fibres you have the more
    suited you are to sports requiring bursts of
    strength and power.
    Consider two sprinters X and Y. They are the same
    age, weight and fitness. But X has 75% fast twitch
    fibres in his legs and Y has 55%.
    Who is the quickest?

    MUSCLE FIBRES and SPORT


    If we jog slowly, only a few of our slow-twitch fibres
    contract to move our legs. When we increase our speed
    we use more slow-twitch fibres. As we run faster our
    fast-twitch fibres also start to contract to help out.
    More and more will start to contract as we run even
    faster. At top speed all of our fast-twitch and slowtwitch fibres will be working.
    MUSCLE CHANGES AND SPORT
    Muscle hypertrophy the muscle increases is size
    Muscle atrophy muscle decreases in size.

    WHAT HAPPENS AS WE EXERCISE?

    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 fibres contract.
    There is a rise in the temperature of the muscle.
    Our stores of Adenosine Triphosphate (ATP) and Creatine Phosphate
    (CP) in the muscles are used up.
    Waste products such as Carbon Dioxide and Lactic Acid build up in the
    muscles.
    These waste products lead to tiredness and cramp.
    Stores of muscle glucose are used up.
    Our ability to carry on may be affected.
    Overuse of muscles can lead to soreness and strains.

    MUSCLE TONE
    Even when a muscle is relaxed, a small number of fibres are
    contracted enough to keep the muscle taut but not enough
    to cause movement.
    This partial state of contraction is called 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 it in turns to contact. They work in relays
    Poor muscle tone leads to poor posture. Exercise improves
    muscle tone it makes the fibres thicker so they contract
    more strongly

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