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					The Muscular System



      Chapter 36
       Section 2
Muscle System Functions
 Provides voluntary
  movement of body
   Enables breathing,
    blinking, and smiling
   Allows you to hop,
    skip, jump, or do
    push-ups
 Maintains posture
 Produces heat
   Functions Continued

 Causes heart beat
 Directs circulation
  of blood
   Regulates
     blood
    pressure
   Sends blood to
    different areas of
    the body
    Functions Continued
 Provides movement of
  internal organs
   Moves food through
    digestive tract
   Enables bladder control
 Causes involuntary
  actions
   Reflex actions
   Adjusts opening of pupils
   Causes hair to stand on
    end (            )
         Muscle Tissue
         Characteristics
 Is made up of                Skeletal
  contractile fibers
 Provides movement
 Controlled by the
  nervous system
   Voluntary- consciously
    controlled               Smooth       Cardiac
   Involuntary- not under
    conscious control
 Examples
   Skeletal
   Smooth
   Cardiac
Types of Muscle Tissue
 There are
  three main
  types of
  muscle tissue
   Skeletal
    (striated)
   Cardiac
    (heart)
   Smooth
    (visceral)
    Comparison of Muscle Types

 Muscle Type         Skeletal            Cardiac           Smooth
                    Attached to           Heart         Walls of internal
   Location            bone                             organs + in skin
                   Movement of       Beating of heart    Movement of
   Function           bone                              internal organs

Control Mode         Voluntary         Involuntary        Involuntary

                  Long + slender       Branching        Spindle shape
    Shape


                   Striated- light     Striated          Non-striated
Characteristics   and dark bands      One or two         One nucleus
                    Many nuclei         nuclei            (visceral)
                                              Frontalis

 Location
of Muscles                                    Masseter

                                                  Deltoid
                                          biceps brachii
                                        Pectoralis Major

  Skeletal                              Brachioradialis
   Muscles        External Obliques
                    Rectus abdominis
    Anterior
     view
                Quadriceps Group
                           Quadriceps
                             group



                    Tibialis Anterior
 Location
of Muscles
                         Trapezius


                  Triceps brachii

 Skeletal                           Latissimus dorsi

  Muscles
   Posterior
    view
                                          Gluteus
                Gastrocnemius             maximus

                 Hamstring
                Hamstring
                    group
                  group
    Muscles You Need to Know
                                 5
                                 A
   1. brachioradialis
   2. biceps brachii                10
                                     F

   3. deltoid                                 15
                                                K
   4. external oblique     3
                            B
                                          11
                                          G
   5. frontalis            C
                            2                      L16
   6. gastrocnemius                      13
                                          H                     9
                                                                O

   7. gluteus maximus      4
                            D                  I
                                               1

   8. hamstring group
   9. latissimus dorsi                                M7
   10. masseter
                                12
   11. pectoralis major         E
                                                            8
                                                            P
   12. quadriceps group
   13. rectus abdominis
   14. tibialis anterior                  J
                                          14       6
                                                   N
   15. trapezius
   16. triceps brachii
    Location of Muscles
 Involuntary
  Muscles
   Diaphragm
   Digestive
    organs
   Arrector pili
   Heart
   Urinary bladder
   Muscles around
    blood vessels
Muscle Tissue Anatomy




                 bundle of muscle
                  fibers – fascicle
        
M
            Muscles are made up of bundles
            of muscle fibers, called fascicles
              Fascicle is a bundle of muscle
u   T           fibers
                   A muscle fiber is a muscle
s   I       A       cell….made up of many
                    small myofibrils
c   s       n           Myofibrils
                         contain filaments       Muscle

l   s       a               Two types of
                             protein
e   u       t                                    Fascicle
                             filaments

    e       o
            m                Muscle Fibers


            y   Myofibrils



    Filaments
Myofibril
                            Thin Filaments

                                      Sarcomere
                                      Sarcomere      Actin
 Contain two types of                              Molecule
  protein filaments
    Actin- thin
     protein
                             Z Disc
     filaments
    Myosin- thick
     protein filaments
    Z disc- point of
     anchor of actin         Thick Filaments

    Sarcomere-
     functional unit of a
     myofibril, region
     between Z discs,
                                  Myosin Molecule
                  Muscle Tissue
                    Anatomy
                 What parts do you
    D
    1
                  remember?
                   1. Muscle
                   2. Fascicle
                      (bundle of fibers)
                   3. Muscle fiber
C
2
                      (muscle cell)
                   4. Myofibrils
        B
        3
            4
            A
Muscle Tissue Anatomy Continued
 What parts do you remember?....continued
                  Actin
                 F               Muscle cell
                                C

                  Fascicle
                 B               Myofibrils
                                D
 A
                  Filaments
                 E               Myosin
                                G
   B
     C            Muscle
                 A
                                 Sarcomere
                                H
                                 Z Disc
                                 I
   Myofibril
      H

                                    D

                                                E



                                        I   G       F
        Mechanics of a Muscle
            Contraction
     What stimulates a muscle to
      contract?
         Your nervous system
     What cells are involved?
         Muscle cells and a motor neuron
         Motor neuron sends
          impulse to muscle cells
         One neuron will form
          synapses with many
          muscle cells
     What is this called?
       A motor unit
       Let’s take a look under
A       the microscope.…
    motor unit
       Mechanics of a Muscle
           Contraction
     Where does stimulation occur?
          Neuromuscular junction
     How do motor neurons
      communicate with
      muscle cells?
          Neurotransmitters (typically
           acetylcholine) carry
           impulse signal across the gap
     What happens when a
      muscle cell is stimulated?
          Calcium ions are released into the muscle cell
                                                            Neurotransmitters
Myofibrils are
surrounded by
   calcium-
  containing
 sarcoplasmic
  reticulum.
 Mechanics of a Muscle
     Contraction
 What do calcium ions do?
   Cause interaction between actin and myosin
 How do actin and myosin interact?
   Actin filaments slide over the myosin filaments
 What model explains this?
   Sliding Filament Model
 Mechanics of a Muscle
 Contraction
 What causes actin to slide
  over myosin?
    The head of myosin
     connects to actin and
     pivots.
 What is this connection
  called?
    cross-bridge
 The binding of the myosin
  heads throughout the
  sarcomere occur
  asynchronously…
    some myosin heads are
     binding while other heads are
     releasing the actin filaments.
    This process must be
     performed repeatedly during
     a single muscle contraction
     so that the muscle is able to
     generate a smooth force
       Mechanics of a Muscle
           Contraction
 What provides the energy to swivel the head of
  myosin? _____
            ATP
 How exactly does the sliding filament model work?
   In the sliding filament model of muscle contraction, the
    (thin) actin filaments
    [red] (that are attached
    to the Z-line) slide (are
    actually pulled) inward
    along the (thick)
    myosin filaments
    [blue], and the
    sarcomere (measured
    from one Z line to the
    next) is shortened.
 Mechanics of a Muscle
     Contraction
 When each sarcomere becomes shorter it
  causes each myofibril to become shorter.
 When each
  myofibril becomes
  shorter it causes
  the muscle fibers
  to become shorter
 When each
  muscle fiber
  shortens the
  overall muscle                Sarcomere

  contracts.
    Control of a Muscle
       Contraction
 How long does a muscle cell
  remain contracted?
   Until the release of acetylcholine
    stops.
 How strongly does a muscle fiber contract?
   To it’s fullest extent.
   All-or-none response
                      So what controls the
                       strength of a contraction?
                         Number of muscle cells recruited
                         To get a stronger contraction, more
                          cells are stimulated
                         A single cell can’t contract harder
A Closer Look at Muscle Contraction

        “hot”
         guy
                                   Muscle
                                    Fiber


                         Deltoid
                         muscle


                                       Myofibril




                Actin



                                            sarcomere




                Myosin
  Macroscopic Structure
       of Muscle
 _________- attaches
   Tendon
  muscle to bone

 _______- attachment
   Origin
  of muscle to
  immovable (fixed)
  bone (anchors muscle)   Belly of
                          Biceps



 ________- attachment
  Insertion
  to bone that moves
  when muscle contracts

 _____- bulging middle
  Belly
  part of the muscle
    Muscle Movement
 Muscles originate on a _____bone in our body,
                             fixed
                  joint
  cross over a ______, and insert onto a ______
                                             moving
  bone.
 It is important to understand that all muscles
                    move from the ________ point
                                     insertion
                    going toward the __________
                                       origination
                    point.
                    It is because of the placement
                     of the muscles that we can
                     move.
      Muscle Movement
 Tendons
   attach _________ to bone
             muscle
   are inelastic
   don’t stretch when the force of
    the muscle acts on them
 When muscle contracts,
  it pulls on the _______
                    bone
 Individual muscles can
         pull    one
  only ____ in ____ direction
 Muscles work in
               pairs
  opposing ______
       Muscle Movement
 ______- Muscle that bends the joint when
  Flexor
  contracted.
 Extensor Muscle that straightens the joint
  ________-
  when contracted.
 Contracted muscle
  __________
  is short, firm, tight
  and thicker around.
 Relaxed muscle is
  _______
  stretched, long, loose
  and thinner around.
      Muscle Movement
 When the biceps in the arm contracts the triceps
   relaxes
  ________ causing ________ of the arm.
                     bending
 When the triceps in the arm _________ the biceps
                              contracts
  relaxes causing straightening of the arm.
                  ____________
                               ______ of muscles are
                                 Pairs
                                needed because the
                                only active movement
                                            _________
                                of a muscle is to
                                contract to lengthen it
                                _______,
                                          stretched
                                must be _________ by
                                the action of an
                                           muscle
                                opposing _______.
           I am


        Muscle Movement
         getting
         motion
         sicknes


Warning: This illusion
             s



   The muscles, bones, and ligaments work
    together to control body feel
can make youmotion. very
dizzy, especially if you
 are prone to motion
             sickness
       Muscles In Action
         HYPERMUSCLE: MUSCLES IN ACTION

 Click above to get to this multimedia interactive HTML
  document which will help you learn the muscle actions
  of the human body.
Muscle + Bone Interaction
  Let’s review the structures involved in
                          movement at a joint.
                            
                            A   Ligament
        B                 D 
                            C   Tendon
                            
                            G   Cartilage
                            
                            E   Body (Belly)
                  C         
                            D   Origin
                            
                            C   Insertion
                            
                            B   Contracted muscle
                            
                            F   Relaxed muscle
                            
                            B   Flexor
            F
                            
                            F   Extensor
          Muscle Disorders
                      Sprain
   A sprain is a wrenching, twisting or stretching
                  injury to a ligament.




Sprains often affect the
ankles, knees, or wrists.
   Result in pain, swelling, redness, bruising, and
             difficulty using injured joint.
       Muscle Disorders
                   Strain
 A strain is an injury to a muscle or
  tendon, and is often caused by
  overuse, force, or stretching.
                     Injured area
                      experiences:
                        pain and
                         soreness
                        swelling
                        warmth, bruising,
                         or redness
                        difficulty using or
                         moving the
                         injured area in a
                         normal manner
Muscle Disorders
  Muscle Ruptures
    There are three degrees of muscle ruptures
    A muscle tear may be partial or complete and
     caused either by a direct blow or by overexertion.
    A first-degree strain involves less than 5 percent
     of the muscle.
        Mild tears referred to as pulled muscles.
    A second-degree tear is a greater rupture that
     stops short of a complete tear.
        There may be a defect of the muscle - a bump or an
         indentation - at the site of the most pain.
        You should be able to partially contract the muscle,
         but not without pain
    A third-degree rupture is a complete tear across
     the width of the muscle
        You will be unable to contract the muscle.
        This is what happens when someone suddenly
         drops while sprinting.
        Muscle Disorders
  Muscle Pull           Muscle Tear
 Muscle pull- very slight tear
 Chronic tear- gradual onset of pain
 Acute tear- sudden dramatic pain

   Muscle
   Tears
         Muscle Disorders
                  Shin splints
 Shin splints is pain
  resulting from damage to
  the muscles along the shin.
  Pain is felt in different areas,
  depending on which muscles
  are affected.

  Shin splints represent an
  "overuse injury" and occur
  most commonly in runners.
       Muscle Disorders
    Treatment for Muscle Injuries
 R.I.C.E.
 Rest: Stop all activities which
  cause pain.
 Ice: Helps reduce swelling.
  Never ice more than 10-15 min.
  at a time. Protect the skin.
 Compression: Wrap the strained
  area to reduce swelling.
 Elevation: Keep the strained area as
  close to the level of the heart as is
  conveniently possible to keep blood
  from pooling in the injured area.
      Muscle Disorders
      Spasms                     Cramps
 Muscle spasm- when A muscle (or even a few
  fibers of a muscle) involuntarily contract
 Muscle cramp- involuntarily + forcibly
  contracted muscle that does not relax
   A forceful + sustained spasm
   Nick named charley horse
     Muscle feels tied up in knots
          Can last anywhere from a few
           seconds to a quarter of an hour
          Caused by strain or injury
         Muscle Disorders
                   Tetanus
 Tetanus is a preventable disease through vaccination
 Caused by bacteria that            enters the body
  through the skin
 Found in soil, dust and            manure
 Toxin bacteria produces interferes with nerve
  transmission to your muscles and causes
  them to seize up in painful spasms.
 Tetanus typically starts in the jaw and muscles
  of the face, quickly spreading to the arms and legs.
                                     “Lockjaw”
                                     Difficulty swallowing
                                     Intestines often seize up
                                     Bladder fails to empty
                                     Asphyxiation
                                     Cardiac arrest
           Muscle Disorders
                 Anabolic Steroids
 Produced naturally by the body to support such functions as
  fighting stress and promoting growth and development
 Referred to as roids, juice, hype, weight trainers, gym candy,
  arnolds, stackers, or pumpers
 People use steroid pills, gels, creams, or injections to improve their
  sports performance or the way they look.
 Anabolic steroids cause many different types of problems
                   types of problems
                       premature balding or hair loss
                       dizziness
                       mood swings
                       problems sleeping
                       nausea and vomiting
                       high blood pressure
                       aching joints
                       urinary problems
                       shortening of final adult height
                       increased risk of heart disease,
                        stroke, and some cancers
         Muscle Disorders
               Cerebral Palsey
 Cerebral palsy is a group of disorders that affect a
  person's ability to move and to maintain balance and
                     posture.
                      The disorders appear in the
                       first few years of life, and
                       usually don’t get worse over time.
                      People with cerebral palsy
                       may have difficulty walking. They may also
                       have trouble with tasks such as writing or
                       using scissors.
                      Some people with cerebral palsy have other
                       medical conditions, including seizure
                       disorders or mental impairment.
                      Cerebral palsy happens when the areas of
                       the brain that control movement and posture
                       do not develop correctly or get damaged.
         Muscle Disorders
             Muscular Dystrophy
                         Muscular Dystrophy- most well known of
                          hereditary diseases
                         A genetic condition that describes over 20
                          genetic and hereditary muscle diseases.
                         Characterized by progressive skeletal muscle
                          weakness, defects in muscle proteins, and the
                          death of muscle cells and tissue.
                         In some cases, cardiac and smooth muscles
                          are affected.
                        Principal symptoms:
   Progressive Muscular Wasting (weakness)
   Poor Balance and Frequent Falls
   Walking Difficulty + Waddling Gait
   Limited Range of Movement
   Scoliosis (curvature of the spine)
   Inability to Walk
   Muscle Atrophy and Drooping Eyelids
              Muscle Disorders
                      Myasthenia Gravis
   Myasthenia gravis- chronic autoimmune
    neuromuscular disease characterized by
    varying degrees of weakness of the skeletal
    muscles
   Caused by a defect in the transmission of
    nerve impulses at the neuromuscular junction
   Antibodies (produced by the body's own
    immune system) block, alter, or destroy the
    receptors for acetylcholine at the
    neuromuscular junction which prevents the
    muscle contraction from occurring.
                         The characteristic symptom of myasthenia gravis is fatigability, which
                          means that a muscle that is used repeatedly starts to become weak.
                         The symptoms usually start in the face and spread to the other parts of
                          the body as the disease progresses.
                         Certain muscles such as those that control eye and eyelid movement,
                          facial expression, chewing, talking, and swallowing are often involved
                         The muscles that control breathing and neck and limb movements may
                          also be affected.
                         Patients initially complain of drooping eye lids that get worst as the day
                          goes on; they develop double vision, difficulty talking, and difficulty
                          chewing.
                         Muscle weakness increases during periods of activity and improves
                          after periods of rest.
                 Muscle Disorders
                                  Polio
                      Poliomyelitis, often called polio is an acute
                        viral infectious disease which is spread from
                        person-to-person via the fecal-oral route.
                      The majority of polio infections are asymptomatic.
                      In about 1% of cases the virus enters the (CNS) via the
                        blood stream.
                      Within the CNS, poliovirus infects and
                                              destroys motor
                                              neurons.
Old Polio                                    The destruction of
                                              motor neurons
Asymmetric atrophy
                                              causes muscle
& weakness                                    weakness and
Atrophic right leg                            flaccid paralysis
(arrow) in patient                           Vaccination created
with paralytic polio 70                       by Jonas Salk in
years in past                                 1955 has eliminated
                                              the disease
   Chicken wing
dissection video link
http://blip.tv/file/421508
Tendon
Ligament
Cartilage
Bone marrow
A. Phalanges              F. Ulna
B. Manus (hand)           G. Radius
C. Alula (thumb)          H. "Elbow“
D. Metacarpals             I. Humerus
E. Carpal joint (wrist)   J. "Shoulder" joint

				
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posted:4/2/2012
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