MUSCLES

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MUSCLES MUSCLE ACTION
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INTRODUCTION
DID YOU KNOW? DID YOU KNOW? DID YOU KNOW?

• Humans have over 650 muscles which differ in size
  according to the jobs they do.
• These muscles constitute 40 of our  body
  weight. The special function of muscle tissue is
  contraction. 
• CONTRACTION a shortening or tensing of a part or
  organ (especially of a muscle or muscle fiber)

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TYPES OF MUSCLE
TYPES OF MUSCLE

• VOLUNTARY/SKELETAL MUSCLE
• INVOLUNTARY MUSCLE
• CARDIAC MUSCLE

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VOLUNTARY/SKELETAL MUSCLE
VOLUNTARY/SKELETAL MUSCLE

• Muscle that is under the control of the will and
  is generally attached to the skeleton
• Fast acting, Powerful, Eventually will tire
• FOR EXAMPLE Biceps and Deltoids

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INVOLUNTARY MUSCLE
INVOLUNTARY MUSCLE

• Muscle whose activity is not under the control of
  the will it is supplied by the autonomic nervous
  system -The part of the vertebrate that supplies
  stimulation via motor nerves to the smooth and
  cardiac muscles (the involuntary muscles) and to
  the glands of the body
• Slow actingWe do not have conscious
  controlWeak.
• FOR EXAMPLE Muscles of Digestive Tract/Bladder

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CARDIAC MUSCLE
CARDIAC MUSCLE

• A type of muscle with unique features only found
  in the heart. The cardiac muscle is the muscle of
  the heart and medically is called the myocardium.
• Own blood supply Does not tire Fast
  actingPowerful

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FUNCTIONING OF A MUSCLE
FUNCTIONING OF A MUSCLE

• Muscle has only one function and that is to
  contract.Muscles are attached to bones by
  tendons so when a muscle contracts it pulls on
  the bones that it is attached to and the result
  is movement of that bone.The type of movement
  is determined by the joint at which the bone
  occurs.Because a muscle can only contract it can
  not move the bone back to its original position,
  i.e. it can not relax. So muscles usually work in
  pairs of opposites (Antagonistic pairs).

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FUNCTIONING OF A MUSCLE(continued)

• Although muscles are known individually by the
  particular anatomical name, they are also known
  collectively by the type of movement that their
  contraction creates. E.g. When the biceps
  contracts it bends the arm and pulls the hand up
  towards the shoulder. The movement that has
  occurred is flexion at the elbow.
• So the biceps is known as a Flexor muscle.
• The opposite movement is extension and the
  triceps is known as an Extensor muscle

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MUSCLE ATTACHMENT
MUSCLE ATTACHMENT

• Muscles are attached to bones by tendons. Tendons
  are fibrous straps that grow out of the bone and
  into the muscle. They are very strong and
  elastic, indeed the Achilles tendon is the
  strongest thing in the body.

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ORIGIN AND INSERTION

• A muscle is attached to at least two bones.
  These two attachments are different and are
  known by different names
• ORIGIN and INSERTION
• The origin is the point of attachment for the
  muscle to the bone that it is anchored to. The
  point of insertion is the point of attachment for
  the muscle to the bone that it moves.
• EX The point of origin for the Biceps is the
  Scapula and the point of insertion is the radius
  i.e. it does not move the scapula but it does
  move the radius. 

ORIGIN AND INSERTION
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DIFFERENT ROLES OF MUSCLE
DIFFERENT ROLES OF MUSCLE

• Different muscles perform different
  functionssometimes at different times

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AGONIST (Prime Mover)
AGONIST (Prime Mover)

• This is the muscle whose contraction and
  subsequent pull on the insertion tendon creates
  the movement
• EX the hamstrings when bending the leg to
  run.

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ANTAGONIST
ANTAGONIST

• This is the muscle that is relatively passive
  during the movement, but that will become the
  prime mover when the body part is returned to its
  original position
• EX the quadriceps during the first part of the
  stride when running.

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SYNERGIST

• This is the muscle that helps to stabilize the
  body part that is being moved.
• It is adjacent to the insertion tendon.
• EX around the elbow during the bicep curl
  (Biceps is the agonist, Triceps is antagonist).
  

SYNERGIST
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FIXATOR
FIXATOR

• This is the muscle that provides stability at the
  point of origin for the working muscle, -
• EX The muscles of the shoulder and upper back
  during the bicep curl.

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TYPES OF MUSCLE FIBER
TYPES OF MUSCLE FIBER

• Muscle Fiber can be either
• SLOW TWITCH (Type 1)
• Endurance Fiber, works well with oxygen, aerobic
  Ex Long Distance Runners
• FAST TWITCH (Type 2)
• Power Fiber, Quick Bursts
• anaerobic Ex. Sprinters, Power Lifters

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Slow-Twitch Slow-twitch fibres contract slowly
and can be used for longer periods of time.
Postural muscle of the back are composed of
mostly slow-twitch muscle fibers. Athletes who
run long distances need more slow-twitch fibers
in their legs. Slow-twitch muscle fibers rely on
oxygen as their main energy source.
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Fast-Twitch Fast-twitch fibers contract quickly
and provide strength and speed, though they also
fatigue more quickly. Sprinters require short but
intense bursts of energy and therefore need more
fast-twitch muscle fibers. Fast-twitch muscle
fibers rely on ATP and glycogen as their main
energy source. As ATP sources can be rapidly
depleted, lactic acid is a by product of the
breakdown of glycogen, fast-twitch fibers can
only be active for a short period of time. .