SlideShare a Scribd company logo
Muscles

VTT 235 Anatomy & Physiology
Muscle…
 Muscle is one of the four basic tissues of
  the body.
 It is made up of cells that can shorten or
  contract.
 Skeletal muscle is voluntary and is
  responsible for movement of the bones.
 Cardiac muscle is involuntary and is found
  only in the heart.
 Smooth muscle is involuntary and is found
  all over the body including blood vessels,
  the bladder, and the intestines.
SKELETAL MUSCLE
Muscle Attachments
 Most muscles are attached to bones
  at both ends by tendons.
 A few muscles are attached to bones
  or to other muscles by aponeuroses.
   The most prominent aponeurosis is the
    linea alba.
Muscle Attachments…
 Origin:
   Site of muscle attachment that is more
    stable.
   The origin has the least amount of
    movement during muscle contraction.
 Insertion:
   The site of muscle attachment that
    undergoes the most movement during
    contraction.
Muscle Actions
 When stimulated by a nerve impulse,
  a muscle contracts.
   It shortens by pulling on its attachment
    sites to produce movement.
 A prime mover (agonist) is a muscle
  that produces a desired movement.
 An antagonist opposes the action of a
  prime mover.
Muscle Actions…
 A synergist is a muscle that contracts
  at the same time as a prime mover
  and assists it in carrying out its
  action.
 Fixator muscles stabilize joints to
  allow other movements to take place.
Muscle Names
 Muscles are often named for physical
  characteristics such as:
   Action- names can be related to a
    muscles function (flexors).
   Shape
   Location
   Direction of fibers
   Number or heads or divisions
   Attachment sites
Microscopic Anatomy of Skeletal
             Muscle
 Skeletal muscle cells are huge.
 They are not very wide, but they are
  very long and thin.
   They are usually referred to as skeletal
    muscle fibers because of their length.
 They have many nuclei located just
  beneath the sarcolemma (muscle cell
  membrane).
Microscopic Anatomy of Skeletal
             Muscle…
 Most of the volume of skeletal muscle
  fiber is made up of thousands of myofibrils
  packed together lengthwise.
   Myofibrils are composed of thousands of even
    tinier contractile protein filaments.
   The two primary proteins that make up the
    filaments are:
      Thin actin filaments.
      Thick myosin filaments.
Skeletal Muscle Contraction
 When a muscle fiber is relaxed, the actin
  and myosin filaments overlap a little.
 When a muscle is stimulated to contract,
  small levers on the myosin filaments called
  cross bridges, ratchet back and forth and
  pull the actin filaments on either side of
  the myosin filaments towards the center of
  the myosin filaments.
 This causes the filaments to slide over
  each other and shorten the sarcomere.
Myosin
Actin
Skeletal Muscle Contraction…
 Muscle fibers store glucose as glycogen
  and oxygen as myoglobin.

 Muscles utilize aerobic metabolism as long
  as the oxygen supply is adequate to keep up
  with the energy needs of the fiber.
   The maximum amount of energy is extracted
    from each glucose molecule.
Skeletal Muscle Contraction…
 When the oxygen runs out, muscles switch
  to anaerobic metabolism.
   Its not as efficient.
   Results in lactic acid formation as a byproduct
    of incomplete glucose breakdown.
   Lactic acid accumulates in muscles and makes
    them sore.
   It diffuses back into the blood and goes to the
    liver, where it is converted back into glucose.
Heat Production
 A considerable amount of energy
  from muscles is produced in the form
  of heat.
 Under cold conditions, muscles can
  produce heat by shivering.
CARDIAC MUSCLE
Gross Anatomy
 Forms most of the volume of the
  heart & makes up the majority of the
  walls of the cardiac chambers.
 Cardiac muscle cells form elaborate
  networks around the cardiac
  chambers.
Microscopic Anatomy
 Cardiac muscle cells are much smaller than
  skeletal muscle cells.
 They only have one nucleus per cell.
 They are longer then they are wide and
  often have multiple branches.
 The firm end-to-end attachments between
  cardiac muscle cells are visible under the
  microscope as dark, transverse lines
  between cells (fig. 7-1).
Microscopic Anatomy…
 These attachment sites are called
  interclated disks.
   The interclated disks securely fasten
    the cells together & also transmit
    impulses from cell to cell to allow large
    groups of cells to contract in a
    coordinated manner.
Physiology…
 Rather than large numbers of muscle cells
  contracting at the same time, as in skeletal
  muscle, cardiac muscle cells contract in a
  rapid, wavelike fashion.
 The impulse that coordinates the
  contractions spreads from cell to cell
  across the interclated disks like a wave.
 That rapid, wavelike contraction
  effectively squeezes blood out of the
  cardiac chambers.
Physiology…
 For blood to move through the chambers of
  the heart, these contractions must be
  carefully initiated and controlled.
 That is the job of the heart’s internal
  impulse conduction system.
   This system consists entirely of cardiac muscle
    cells.
   The impulse that starts each heartbeat begins
    in the heart’s “pacemaker” the SA node.
SMOOTH MUSCLE
Gross Anatomy
 Smooth muscle is found all over the
  body in two main forms:
   As large sheets in the walls of some
    hollow organs called visceral smooth
    muscle.
   As small, discrete groups of cells called
    multiunit smooth muscle.
Microscopic Anatomy
 Smooth muscle cells are small and spindle shaped
  with a single nucleus center.

 Because their contractile units are not organized
  into regular, parallel sarcomeres, individual smooth
  muscle cells can shorten to a greater extent than
  the other types of muscle cells.
Physiology- Visceral Smooth Muscle

 Visceral smooth muscle is found in the walls
  of many soft internal organs.
 Contractions occur in large, rhythmic
  waves.
 These contractions can be very strong for
  example:
   Peristaltic contractions
   Uterine contractions
Physiology- Multiunit Smooth Muscle

 Multiunit smooth muscle is small and
  delicate.
 It is found where delicate
  contractions are needed:
   Iris & ciliary body of the eye.
   Walls of small blood vessels.
   Air passages in the lungs.
SELECTED SKELETAL
       MUSCLES

Muscles you will need to identify
     for your lab practical
Muscles of the Face
 Masseter- closes
  the jaw
Thoracic Limb Muscles
 Extrinsic Shoulder-
  1. Trapezius- elevates
    the scapula.
  2. **Latissimus dorsi-
    flexes the shoulder.
  3. **Brachiocephalicus-
    advances the limb or
    draws the head
    laterally.
Thoracic Limb Muscles
 Extrinsic Shoulder-
  4. Serratus ventralis-
    supports the trunk.
  5. Superficial pectoral-
    adducts and advances
    the limb.
  6. Deep pectoral- draws
    the limb caudally
    (flexes the shoulder).
Thoracic Limb Muscles
 Intrinsic shoulder-
  7. Deltoid- flexes the
    shoulder.
  8. Brachialis- flexes the
    elbow.
Thoracic Limb Muscles
 Intrinsic shoulder-
  9. Biceps brachii-
    extends the shoulder
    and flexes the elbow.
  10. **Triceps brachii-
    extends the elbow, the
    long head flexes the
    shoulder.
Forearm Muscles
 11.) Extensors-
   A-Extensor Carpi
    Radialis- extends the
    carpus, flexes the
    elbow.
   B- Common Digital
    Extensor- extends
    the digits & carpus.
   C- Lateral Digital
    Extensor- extends
    the digits & carpus.
   D- Extensor Carpi
    Ulnaris- flexes the
    carpus.
Thoracic Limb Muscles
 12.) Flexors-
   A- Flexor Carpi
    Radialis- flexes the
    carpus.
   B- Flexor Carpi
    Ulnaris- flexes the
    carpus.
   C- Superficial Digital
    Flexor- flexes the
    carpus & digits.
   D- Deep Digital
    Flexor- flexes the
    carpus & digits.
Thorax Muscles
 Intercostals- involved in respiration
 Diaphragm- separates the thoracic
  and abdominal cavities, main muscle of
  respiration.
Trunk Muscles
 13. Epaxials-
   Lies above the
    vertebral column.
   supports the spine.
 14. Hypaxials-
   Lies below the
    vertebral column.
   They flex the neck &
    tail contributes to the
    flexion of the
    vertebral coloumn.
Pelvic Limb Muscles
 15.) **Superficial
  Gluteal- abducts the
  limb.
 Middle Gluteal-
  Extends the thigh.
 Deep Gluteal-
  extends the limb.
Pelvic Limb Muscles
 Hamstring Group-
  extends the hip, stifle, &
  tarsus, flexes the stifle.
 All originate from the
  ischiatic tuberosity,
   16.) Biceps femoris-
      Inserts into the patella.
   17.) **Semitendinosus-
      Inserts into the tibia.
   18.) **Semimembranosus-
      Inserts into the femur &
       tibia.
Pelvic Limb Muscles
 19.) **Gracialis-
   Originates in the
    pelvic symphysis.
   Inserts into the
    medial side of the
    stifle.
   Adducts the limb.
 20.) **Sartorius-
   Originates in the ilium.
   Inserts into the
    medial side of the
    stifle.
   Flexes the hip & stifle.
Pelvic Limb Muscles
 21.) Quadriceps femoris-
   Rectus femoris-
      Originates in the ilium.
      Inserts into the patella.
      Flexes the hip, extends the
       stifle.
   Vastus: lateralis,
    medialis, intermedius-
      Originates in the proximal
       femur.
      Inserts into the patella.
      Extends the stifle.
Pelvic Limb Muscles
 22.) Adductor-
   Originates in the ventral
    surface of the hip bones.
   Inserts into the femur.
   Adducts the limb.
 23.) **Gastrocnemius-
   Originates in the caudal
    surface of the femur.
   Inserts into the
    calcanean tuberosity.
   Extends the tarsus,
    flexes the stifle.
Abdominal Muscles
 24.) Obliques:
   External- extends from the ribs to the ventral
    midline.
   Internal- muscle fibers run obliquely and cross with
    the external oblique.
 25.) Transversus abdominus- the deepest
  abdominal muscle terminating at the linea alba.
 26.) Rectus abdominus- two long, straight
  muscles extending from the sternum along the
  ventral abdomen.
 27.) **Linea Alba- the fibrous cord formed by
  the joining of the abdominal muscles.
THE END

More Related Content

What's hot

Myology
MyologyMyology
Myology
xayouluma
 
The muscular system
The muscular systemThe muscular system
The muscular system
A Anush Alvaro
 
The myology
The myologyThe myology
The myology
ebrahim mahmoud
 
Muscle tissue 1 2 (comparative vertebrate anatomy)
Muscle tissue 1 2 (comparative vertebrate anatomy)Muscle tissue 1 2 (comparative vertebrate anatomy)
Muscle tissue 1 2 (comparative vertebrate anatomy)
Biologist.R
 
Skeletal and Muscular System
Skeletal and Muscular System Skeletal and Muscular System
Skeletal and Muscular System
Jenny Dixon
 
Muscular system
Muscular systemMuscular system
Muscular system
pavithra M
 
Muscular System
Muscular SystemMuscular System
Muscular System
Chelsea Mareé
 
Muscular System Overview
Muscular System OverviewMuscular System Overview
Muscular System Overview
levouge777
 
Muscles and Muscular System in Humans and Animals
Muscles and Muscular System in Humans and AnimalsMuscles and Muscular System in Humans and Animals
Muscles and Muscular System in Humans and Animals
Catherine Patterson
 
Chap10 powerpoint Muscular System
Chap10 powerpoint Muscular SystemChap10 powerpoint Muscular System
Chap10 powerpoint Muscular System
kevperrino
 
Myology ppt
Myology pptMyology ppt
Myology ppt
Luay Hammza
 
Muscles ppt aw
Muscles ppt awMuscles ppt aw
Muscles ppt aw
ryanm9
 
General anatomy of muscles
General anatomy of muscles General anatomy of muscles
General anatomy of muscles
ritika patel
 
Muscles 1
Muscles 1Muscles 1
Muscles 1
Kevin Young
 
INVOLUNTARY MUSCLES
INVOLUNTARY MUSCLESINVOLUNTARY MUSCLES
INVOLUNTARY MUSCLES
saranyasreejith
 
Chapter 8 & 15 muscular
Chapter 8 & 15   muscularChapter 8 & 15   muscular
Chapter 8 & 15 muscular
Adam Tablante
 
Muscles
MusclesMuscles
Muscles
Aarif Kanadia
 
Locomotion System
Locomotion SystemLocomotion System
Locomotion System
Sean Lemuel Santos
 
The Muscular System of Human Body
The Muscular System of Human BodyThe Muscular System of Human Body
The Muscular System of Human Body
UmairKhan463
 
10 Muscle Tissue And Organization
10 Muscle Tissue And Organization10 Muscle Tissue And Organization
10 Muscle Tissue And Organization
Kevin Young
 

What's hot (20)

Myology
MyologyMyology
Myology
 
The muscular system
The muscular systemThe muscular system
The muscular system
 
The myology
The myologyThe myology
The myology
 
Muscle tissue 1 2 (comparative vertebrate anatomy)
Muscle tissue 1 2 (comparative vertebrate anatomy)Muscle tissue 1 2 (comparative vertebrate anatomy)
Muscle tissue 1 2 (comparative vertebrate anatomy)
 
Skeletal and Muscular System
Skeletal and Muscular System Skeletal and Muscular System
Skeletal and Muscular System
 
Muscular system
Muscular systemMuscular system
Muscular system
 
Muscular System
Muscular SystemMuscular System
Muscular System
 
Muscular System Overview
Muscular System OverviewMuscular System Overview
Muscular System Overview
 
Muscles and Muscular System in Humans and Animals
Muscles and Muscular System in Humans and AnimalsMuscles and Muscular System in Humans and Animals
Muscles and Muscular System in Humans and Animals
 
Chap10 powerpoint Muscular System
Chap10 powerpoint Muscular SystemChap10 powerpoint Muscular System
Chap10 powerpoint Muscular System
 
Myology ppt
Myology pptMyology ppt
Myology ppt
 
Muscles ppt aw
Muscles ppt awMuscles ppt aw
Muscles ppt aw
 
General anatomy of muscles
General anatomy of muscles General anatomy of muscles
General anatomy of muscles
 
Muscles 1
Muscles 1Muscles 1
Muscles 1
 
INVOLUNTARY MUSCLES
INVOLUNTARY MUSCLESINVOLUNTARY MUSCLES
INVOLUNTARY MUSCLES
 
Chapter 8 & 15 muscular
Chapter 8 & 15   muscularChapter 8 & 15   muscular
Chapter 8 & 15 muscular
 
Muscles
MusclesMuscles
Muscles
 
Locomotion System
Locomotion SystemLocomotion System
Locomotion System
 
The Muscular System of Human Body
The Muscular System of Human BodyThe Muscular System of Human Body
The Muscular System of Human Body
 
10 Muscle Tissue And Organization
10 Muscle Tissue And Organization10 Muscle Tissue And Organization
10 Muscle Tissue And Organization
 

Similar to Lp 3 muscles

The muscular system
The muscular systemThe muscular system
The muscular system
Vanja Drljevic
 
Muscles of Mastication
Muscles of MasticationMuscles of Mastication
Muscles of Mastication
MANJIMA KHANDELWAL
 
The muscular-system-powerpoint-1227697713114530-8
The muscular-system-powerpoint-1227697713114530-8The muscular-system-powerpoint-1227697713114530-8
The muscular-system-powerpoint-1227697713114530-8
Victor Venida
 
VC Lesson2 Muscular System
VC Lesson2 Muscular SystemVC Lesson2 Muscular System
VC Lesson2 Muscular System
Arlene Salustiano
 
The Muscular System Powerpoint
The Muscular System   PowerpointThe Muscular System   Powerpoint
The Muscular System Powerpoint
angellacx
 
The muscular-system-powerpoint dr. bantiles
The muscular-system-powerpoint dr. bantilesThe muscular-system-powerpoint dr. bantiles
The muscular-system-powerpoint dr. bantiles
itsebo
 
The muscular-system-powerpoint-by DR. BANTILES
The muscular-system-powerpoint-by DR. BANTILESThe muscular-system-powerpoint-by DR. BANTILES
The muscular-system-powerpoint-by DR. BANTILES
itsebo
 
The Muscular System Powerpoint 1227697713114530 8
The Muscular System Powerpoint 1227697713114530 8The Muscular System Powerpoint 1227697713114530 8
The Muscular System Powerpoint 1227697713114530 8
VhIee JHay Estrada
 
The muscular-system-powerpoint-1227697713114530-8
The muscular-system-powerpoint-1227697713114530-8The muscular-system-powerpoint-1227697713114530-8
The muscular-system-powerpoint-1227697713114530-8
itsebo
 
UNIT- 14 THE MUSCULAR SYSTEM.ANATOMY ptx
UNIT- 14 THE MUSCULAR SYSTEM.ANATOMY ptxUNIT- 14 THE MUSCULAR SYSTEM.ANATOMY ptx
UNIT- 14 THE MUSCULAR SYSTEM.ANATOMY ptx
MrsRainaJeniferMasca
 
MUSCLE - 15903 by SSG muscle anatomy of upper limb lower limb and all
MUSCLE - 15903 by SSG  muscle anatomy of upper limb lower limb and allMUSCLE - 15903 by SSG  muscle anatomy of upper limb lower limb and all
MUSCLE - 15903 by SSG muscle anatomy of upper limb lower limb and all
ArchanaVekariya
 
Muscular System.ppt
Muscular System.pptMuscular System.ppt
Muscular System.ppt
FrancisEtseyDushie
 
Introduction to the muscular system
Introduction to the muscular systemIntroduction to the muscular system
Introduction to the muscular system
sania aslam
 
L4 Muscles1
L4 Muscles1L4 Muscles1
L4 Muscles1
Marc Potter
 
Muscular System.pptx
Muscular System.pptxMuscular System.pptx
Muscular System.pptx
AmrElmoghazy2
 
Anatomy lab. 5 muscles
Anatomy lab. 5 musclesAnatomy lab. 5 muscles
Anatomy lab. 5 muscles
Lama K Banna
 
the-muscular-system.ppt
the-muscular-system.pptthe-muscular-system.ppt
the-muscular-system.ppt
CaressieBiscoBuenafl
 
The muscular-system-powerpoint-1227697713114530-8
The muscular-system-powerpoint-1227697713114530-8The muscular-system-powerpoint-1227697713114530-8
The muscular-system-powerpoint-1227697713114530-8
harley harris
 
Muscular system in insects
Muscular system in insectsMuscular system in insects
Muscular system in insects
Jayantyadav94
 
muscular system
muscular systemmuscular system

Similar to Lp 3 muscles (20)

The muscular system
The muscular systemThe muscular system
The muscular system
 
Muscles of Mastication
Muscles of MasticationMuscles of Mastication
Muscles of Mastication
 
The muscular-system-powerpoint-1227697713114530-8
The muscular-system-powerpoint-1227697713114530-8The muscular-system-powerpoint-1227697713114530-8
The muscular-system-powerpoint-1227697713114530-8
 
VC Lesson2 Muscular System
VC Lesson2 Muscular SystemVC Lesson2 Muscular System
VC Lesson2 Muscular System
 
The Muscular System Powerpoint
The Muscular System   PowerpointThe Muscular System   Powerpoint
The Muscular System Powerpoint
 
The muscular-system-powerpoint dr. bantiles
The muscular-system-powerpoint dr. bantilesThe muscular-system-powerpoint dr. bantiles
The muscular-system-powerpoint dr. bantiles
 
The muscular-system-powerpoint-by DR. BANTILES
The muscular-system-powerpoint-by DR. BANTILESThe muscular-system-powerpoint-by DR. BANTILES
The muscular-system-powerpoint-by DR. BANTILES
 
The Muscular System Powerpoint 1227697713114530 8
The Muscular System Powerpoint 1227697713114530 8The Muscular System Powerpoint 1227697713114530 8
The Muscular System Powerpoint 1227697713114530 8
 
The muscular-system-powerpoint-1227697713114530-8
The muscular-system-powerpoint-1227697713114530-8The muscular-system-powerpoint-1227697713114530-8
The muscular-system-powerpoint-1227697713114530-8
 
UNIT- 14 THE MUSCULAR SYSTEM.ANATOMY ptx
UNIT- 14 THE MUSCULAR SYSTEM.ANATOMY ptxUNIT- 14 THE MUSCULAR SYSTEM.ANATOMY ptx
UNIT- 14 THE MUSCULAR SYSTEM.ANATOMY ptx
 
MUSCLE - 15903 by SSG muscle anatomy of upper limb lower limb and all
MUSCLE - 15903 by SSG  muscle anatomy of upper limb lower limb and allMUSCLE - 15903 by SSG  muscle anatomy of upper limb lower limb and all
MUSCLE - 15903 by SSG muscle anatomy of upper limb lower limb and all
 
Muscular System.ppt
Muscular System.pptMuscular System.ppt
Muscular System.ppt
 
Introduction to the muscular system
Introduction to the muscular systemIntroduction to the muscular system
Introduction to the muscular system
 
L4 Muscles1
L4 Muscles1L4 Muscles1
L4 Muscles1
 
Muscular System.pptx
Muscular System.pptxMuscular System.pptx
Muscular System.pptx
 
Anatomy lab. 5 muscles
Anatomy lab. 5 musclesAnatomy lab. 5 muscles
Anatomy lab. 5 muscles
 
the-muscular-system.ppt
the-muscular-system.pptthe-muscular-system.ppt
the-muscular-system.ppt
 
The muscular-system-powerpoint-1227697713114530-8
The muscular-system-powerpoint-1227697713114530-8The muscular-system-powerpoint-1227697713114530-8
The muscular-system-powerpoint-1227697713114530-8
 
Muscular system in insects
Muscular system in insectsMuscular system in insects
Muscular system in insects
 
muscular system
muscular systemmuscular system
muscular system
 

More from Kirstyn Soderberg

Lp 17 endocrinology 2009
Lp 17 endocrinology 2009Lp 17 endocrinology 2009
Lp 17 endocrinology 2009
Kirstyn Soderberg
 
Lp 16a reproductive system
Lp 16a reproductive systemLp 16a reproductive system
Lp 16a reproductive system
Kirstyn Soderberg
 
Lp 16 urinary system & urinalysis 2008
Lp 16 urinary system & urinalysis 2008Lp 16 urinary system & urinalysis 2008
Lp 16 urinary system & urinalysis 2008
Kirstyn Soderberg
 
Lp 14 digestive system 2009
Lp 14 digestive system 2009Lp 14 digestive system 2009
Lp 14 digestive system 2009
Kirstyn Soderberg
 
Lp 13 respiratory system 2008
Lp 13 respiratory system 2008Lp 13 respiratory system 2008
Lp 13 respiratory system 2008
Kirstyn Soderberg
 
Lp 12 cardiovascular
Lp 12 cardiovascularLp 12 cardiovascular
Lp 12 cardiovascular
Kirstyn Soderberg
 
Lp 8 neurology 2008
Lp 8 neurology 2008Lp 8 neurology 2008
Lp 8 neurology 2008
Kirstyn Soderberg
 
Lp 5 bones 2008 no path
Lp 5 bones 2008 no pathLp 5 bones 2008 no path
Lp 5 bones 2008 no path
Kirstyn Soderberg
 
Lp 4 joints 2008
Lp 4 joints 2008Lp 4 joints 2008
Lp 4 joints 2008
Kirstyn Soderberg
 

More from Kirstyn Soderberg (9)

Lp 17 endocrinology 2009
Lp 17 endocrinology 2009Lp 17 endocrinology 2009
Lp 17 endocrinology 2009
 
Lp 16a reproductive system
Lp 16a reproductive systemLp 16a reproductive system
Lp 16a reproductive system
 
Lp 16 urinary system & urinalysis 2008
Lp 16 urinary system & urinalysis 2008Lp 16 urinary system & urinalysis 2008
Lp 16 urinary system & urinalysis 2008
 
Lp 14 digestive system 2009
Lp 14 digestive system 2009Lp 14 digestive system 2009
Lp 14 digestive system 2009
 
Lp 13 respiratory system 2008
Lp 13 respiratory system 2008Lp 13 respiratory system 2008
Lp 13 respiratory system 2008
 
Lp 12 cardiovascular
Lp 12 cardiovascularLp 12 cardiovascular
Lp 12 cardiovascular
 
Lp 8 neurology 2008
Lp 8 neurology 2008Lp 8 neurology 2008
Lp 8 neurology 2008
 
Lp 5 bones 2008 no path
Lp 5 bones 2008 no pathLp 5 bones 2008 no path
Lp 5 bones 2008 no path
 
Lp 4 joints 2008
Lp 4 joints 2008Lp 4 joints 2008
Lp 4 joints 2008
 

Lp 3 muscles

  • 1. Muscles VTT 235 Anatomy & Physiology
  • 2. Muscle…  Muscle is one of the four basic tissues of the body.  It is made up of cells that can shorten or contract.  Skeletal muscle is voluntary and is responsible for movement of the bones.  Cardiac muscle is involuntary and is found only in the heart.  Smooth muscle is involuntary and is found all over the body including blood vessels, the bladder, and the intestines.
  • 4. Muscle Attachments  Most muscles are attached to bones at both ends by tendons.  A few muscles are attached to bones or to other muscles by aponeuroses.  The most prominent aponeurosis is the linea alba.
  • 5. Muscle Attachments…  Origin:  Site of muscle attachment that is more stable.  The origin has the least amount of movement during muscle contraction.  Insertion:  The site of muscle attachment that undergoes the most movement during contraction.
  • 6. Muscle Actions  When stimulated by a nerve impulse, a muscle contracts.  It shortens by pulling on its attachment sites to produce movement.  A prime mover (agonist) is a muscle that produces a desired movement.  An antagonist opposes the action of a prime mover.
  • 7. Muscle Actions…  A synergist is a muscle that contracts at the same time as a prime mover and assists it in carrying out its action.  Fixator muscles stabilize joints to allow other movements to take place.
  • 8. Muscle Names  Muscles are often named for physical characteristics such as:  Action- names can be related to a muscles function (flexors).  Shape  Location  Direction of fibers  Number or heads or divisions  Attachment sites
  • 9. Microscopic Anatomy of Skeletal Muscle  Skeletal muscle cells are huge.  They are not very wide, but they are very long and thin.  They are usually referred to as skeletal muscle fibers because of their length.  They have many nuclei located just beneath the sarcolemma (muscle cell membrane).
  • 10. Microscopic Anatomy of Skeletal Muscle…  Most of the volume of skeletal muscle fiber is made up of thousands of myofibrils packed together lengthwise.  Myofibrils are composed of thousands of even tinier contractile protein filaments.  The two primary proteins that make up the filaments are:  Thin actin filaments.  Thick myosin filaments.
  • 11. Skeletal Muscle Contraction  When a muscle fiber is relaxed, the actin and myosin filaments overlap a little.  When a muscle is stimulated to contract, small levers on the myosin filaments called cross bridges, ratchet back and forth and pull the actin filaments on either side of the myosin filaments towards the center of the myosin filaments.  This causes the filaments to slide over each other and shorten the sarcomere.
  • 13. Skeletal Muscle Contraction…  Muscle fibers store glucose as glycogen and oxygen as myoglobin.  Muscles utilize aerobic metabolism as long as the oxygen supply is adequate to keep up with the energy needs of the fiber.  The maximum amount of energy is extracted from each glucose molecule.
  • 14. Skeletal Muscle Contraction…  When the oxygen runs out, muscles switch to anaerobic metabolism.  Its not as efficient.  Results in lactic acid formation as a byproduct of incomplete glucose breakdown.  Lactic acid accumulates in muscles and makes them sore.  It diffuses back into the blood and goes to the liver, where it is converted back into glucose.
  • 15. Heat Production  A considerable amount of energy from muscles is produced in the form of heat.  Under cold conditions, muscles can produce heat by shivering.
  • 17. Gross Anatomy  Forms most of the volume of the heart & makes up the majority of the walls of the cardiac chambers.  Cardiac muscle cells form elaborate networks around the cardiac chambers.
  • 18. Microscopic Anatomy  Cardiac muscle cells are much smaller than skeletal muscle cells.  They only have one nucleus per cell.  They are longer then they are wide and often have multiple branches.  The firm end-to-end attachments between cardiac muscle cells are visible under the microscope as dark, transverse lines between cells (fig. 7-1).
  • 19. Microscopic Anatomy…  These attachment sites are called interclated disks.  The interclated disks securely fasten the cells together & also transmit impulses from cell to cell to allow large groups of cells to contract in a coordinated manner.
  • 20. Physiology…  Rather than large numbers of muscle cells contracting at the same time, as in skeletal muscle, cardiac muscle cells contract in a rapid, wavelike fashion.  The impulse that coordinates the contractions spreads from cell to cell across the interclated disks like a wave.  That rapid, wavelike contraction effectively squeezes blood out of the cardiac chambers.
  • 21. Physiology…  For blood to move through the chambers of the heart, these contractions must be carefully initiated and controlled.  That is the job of the heart’s internal impulse conduction system.  This system consists entirely of cardiac muscle cells.  The impulse that starts each heartbeat begins in the heart’s “pacemaker” the SA node.
  • 23. Gross Anatomy  Smooth muscle is found all over the body in two main forms:  As large sheets in the walls of some hollow organs called visceral smooth muscle.  As small, discrete groups of cells called multiunit smooth muscle.
  • 24. Microscopic Anatomy  Smooth muscle cells are small and spindle shaped with a single nucleus center.  Because their contractile units are not organized into regular, parallel sarcomeres, individual smooth muscle cells can shorten to a greater extent than the other types of muscle cells.
  • 25. Physiology- Visceral Smooth Muscle  Visceral smooth muscle is found in the walls of many soft internal organs.  Contractions occur in large, rhythmic waves.  These contractions can be very strong for example:  Peristaltic contractions  Uterine contractions
  • 26. Physiology- Multiunit Smooth Muscle  Multiunit smooth muscle is small and delicate.  It is found where delicate contractions are needed:  Iris & ciliary body of the eye.  Walls of small blood vessels.  Air passages in the lungs.
  • 27. SELECTED SKELETAL MUSCLES Muscles you will need to identify for your lab practical
  • 28. Muscles of the Face  Masseter- closes the jaw
  • 29. Thoracic Limb Muscles  Extrinsic Shoulder- 1. Trapezius- elevates the scapula. 2. **Latissimus dorsi- flexes the shoulder. 3. **Brachiocephalicus- advances the limb or draws the head laterally.
  • 30. Thoracic Limb Muscles  Extrinsic Shoulder- 4. Serratus ventralis- supports the trunk. 5. Superficial pectoral- adducts and advances the limb. 6. Deep pectoral- draws the limb caudally (flexes the shoulder).
  • 31. Thoracic Limb Muscles  Intrinsic shoulder- 7. Deltoid- flexes the shoulder. 8. Brachialis- flexes the elbow.
  • 32. Thoracic Limb Muscles  Intrinsic shoulder- 9. Biceps brachii- extends the shoulder and flexes the elbow. 10. **Triceps brachii- extends the elbow, the long head flexes the shoulder.
  • 33. Forearm Muscles  11.) Extensors-  A-Extensor Carpi Radialis- extends the carpus, flexes the elbow.  B- Common Digital Extensor- extends the digits & carpus.  C- Lateral Digital Extensor- extends the digits & carpus.  D- Extensor Carpi Ulnaris- flexes the carpus.
  • 34. Thoracic Limb Muscles  12.) Flexors-  A- Flexor Carpi Radialis- flexes the carpus.  B- Flexor Carpi Ulnaris- flexes the carpus.  C- Superficial Digital Flexor- flexes the carpus & digits.  D- Deep Digital Flexor- flexes the carpus & digits.
  • 35.
  • 36. Thorax Muscles  Intercostals- involved in respiration  Diaphragm- separates the thoracic and abdominal cavities, main muscle of respiration.
  • 37. Trunk Muscles  13. Epaxials-  Lies above the vertebral column.  supports the spine.  14. Hypaxials-  Lies below the vertebral column.  They flex the neck & tail contributes to the flexion of the vertebral coloumn.
  • 38. Pelvic Limb Muscles  15.) **Superficial Gluteal- abducts the limb.  Middle Gluteal- Extends the thigh.  Deep Gluteal- extends the limb.
  • 39. Pelvic Limb Muscles  Hamstring Group- extends the hip, stifle, & tarsus, flexes the stifle.  All originate from the ischiatic tuberosity,  16.) Biceps femoris-  Inserts into the patella.  17.) **Semitendinosus-  Inserts into the tibia.  18.) **Semimembranosus-  Inserts into the femur & tibia.
  • 40.
  • 41.
  • 42. Pelvic Limb Muscles  19.) **Gracialis-  Originates in the pelvic symphysis.  Inserts into the medial side of the stifle.  Adducts the limb.  20.) **Sartorius-  Originates in the ilium.  Inserts into the medial side of the stifle.  Flexes the hip & stifle.
  • 43. Pelvic Limb Muscles  21.) Quadriceps femoris-  Rectus femoris-  Originates in the ilium.  Inserts into the patella.  Flexes the hip, extends the stifle.  Vastus: lateralis, medialis, intermedius-  Originates in the proximal femur.  Inserts into the patella.  Extends the stifle.
  • 44. Pelvic Limb Muscles  22.) Adductor-  Originates in the ventral surface of the hip bones.  Inserts into the femur.  Adducts the limb.  23.) **Gastrocnemius-  Originates in the caudal surface of the femur.  Inserts into the calcanean tuberosity.  Extends the tarsus, flexes the stifle.
  • 45. Abdominal Muscles  24.) Obliques:  External- extends from the ribs to the ventral midline.  Internal- muscle fibers run obliquely and cross with the external oblique.  25.) Transversus abdominus- the deepest abdominal muscle terminating at the linea alba.  26.) Rectus abdominus- two long, straight muscles extending from the sternum along the ventral abdomen.  27.) **Linea Alba- the fibrous cord formed by the joining of the abdominal muscles.
  • 46.

Editor's Notes

  1. Skeletal muscle made up of myofibrils which are made up of the proteins actin and myosin filaments