Movement Unit

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Movement Unit

• Skeletal System Anatomy
• Chapter 6

2
Components

• Includes all of the bones (206 in adults).
• Includes the cartilage and ligaments that occur
  at the joints (Articulations System).

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Functions

• Support of the entire bodys weight.
• Protection of the viscera.
• Production of blood cells (Hemopoesis)
• Storage of minerals and fat
• Allows for flexible body movement

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Types of Bones

• Long longer than wide (femur)
• Short cube shaped LW (talus- foot)
• Flat platelike and have broad surfaces
  (parietal- skull)
• Irregular varied shapes with many places for
  connections (vertebra)
• Round circular (patella- knee)

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Long bone Anatomy

• Periosteum continuous with ligaments and
  tendons. Area where blood vessels enter the
  bone. Fibrous connective tissue.
• Epiphysis expanded portions at each end.
  Contains cancellous bone wrapped in a thin layer
  of compact bone covered by hyaline cartilage
  (articular cartilage).
• Diaphysis shaft of the bone not solid
  contains the medullary cavity with yellow marrow.
  Compact bone wraps this cavity.

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What are Focal Features?
7
Review of Histology

• Compact Bone Osteons, osteocytes, Lacunae,
  Lamellae, hydroxyapatite (Ca(OH2)Ca3(PO4)2
  crystals), central or Haversian canal,
  canaliculi.
• Spongy Bone or Cancellous bone trabeculae, red
  bone marrow.
• New term- Ossification- process of bone formation

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The Skeletal System

• Articulations

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Classification

• Classified based on the type of movement they
  allow.
• 3 major types
• Fibrous Joint immovable and connected by
  fibrous connective tissue (ex plates in skull,
  periodontal ligaments)
• Cartilaginous Joint slight movement and
  fibrocartilage is between the 2 bones (ex betw.
  spinal vertebrae pubic bones)
• Synovial Joint free motion no direct contact
  of bones associated with synovial membranes (Ex
  elbow, ankle, shoulder)

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Fibrous Joints minimal movement

• Sutures seams between bones, found between skull
  bones, form fontanels in children (e.g. coronal)
• Syndesmoses bones farther apart than in a suture
  and are joined by ligaments (e.g. radioulnar)
• Gomphoses specialized joints consisting of pegs
  that fit in sockets (e.g. dentoaveolar)

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Cartilaginous Joints Growth

• Synchondroses 2 bones joined by hyaline
  cartilage (e.g. epiphyseal plates- cartilaginous
  region betw. epiphysis diaphysis of a growing
  bone)
• Symphyses fibrocartilage uniting 2 bones (e.g.
  symphyses pubis, manubriosternal (ribcage))

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Synovial Joints Movable

• Plane or gliding 2 opposed flat surfaces,
  movement confined to one plane (e.g.
  intervertebral)
• Saddle 2 saddle-shaped articulating surfaces
  oriented at right angles (e.g. carpometacarpel-
  wrist/hand)
• Hinge convex cylinder in one bone applied to a
  corresponding concave portion on another bone
  (e.g. elbow and knee)
• Pivot rotation around a single axis. A process
  that rotates within a ring (e.g.
  atlantoaxial-neck)

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Synovial Joints

• Ball and Socket ball (head) at the end of one
  bone and a socket on another bone (e.g. coxal-hip
  and glenohumeral-shoulder)
• Ellipsoid modified ball-and-socket the head is
  more ellipsoid in shape rather than round (e.g.
  atlanooccipital- betw.head neck i.e. allows
  nodding)

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Types Movements

• Flexion (anterior or ventral direction) and
  extension (posterior or dorsal direction)
• Dorsiflexion (flex toes) and plantar flexion
  (point toes)
• Abduction (away from midline) and adduction
  (toward midline)
• Medial and lateral rotation (turning around long
  axis)
• Circumduction (combination of flexion, extension,
  abduction, and adduction)
• Elevation (superior motion) and depression
  (inferior motion)
• Protraction (moving in anterior direction) and
  retraction (moving in posterior direction)
• Supination (face up palm) and pronation (face
  down palm)
• Opposition (thumb to finger) and reposition
• Lateral excursion (bottom jaw lateral)
• Inversion (ankle medial turn) and eversion (ankle
  lateral turn)

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Muscular System

• Chapter 7
• Movement Unit

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Fig. 7.1
Review
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Functions of Skeletal Muscle

• Support the body (opposes the force of gravity)
• Make bones and other body parts move
• Maintain a constant body temperature
• Assist movement in cardiovascular and lymphatic
  vessels
• Protect internal organs and stabilize joints

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Microscopic Anatomy of Skeletal Muscle

• What do we already know from histology?
  Striations.
• Arrangement of myofilaments in a muscle fiber
  (cell).
• Normal cell with some specialized terms for cell
  parts. (Plasma membrane sarcolema, endoplasmic
  reticulum sarcoplasmic reticulum)

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Microscopic Anatomy of Muscle (Sarcoplasmic
Reticulum)

• Remember this is the ER for muscle cells.
• Sarcoplasmic reticulum has specialized pockets to
  store calcium ions (Ca2) which is essential for
  muscle contraction.
• The sarcoplasmic reticulum encases hundreds of
  myofibrils which allow for contraction of the
  muscle cell.

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Microscopic Anatomy of Muscle

• Myofibrils run the length of the muscle fiber.
• Striations are formed by the placement of these
  myofibrils forming sarcomeres.
• Sarcomeres contain two types of protein fibers
  actin (thin and intertwined) and myosin (thick
  and shaped like golf club).

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Muscles Move Skeletal Parts

• Skeletal Muscle
• Each muscle fiber is a single cell with many
  nuclei
• Each fiber is composed of a bundle of myofibrils
  which contain myofilaments
• Thin filaments2 strands of actin
• Thick filamentsstaggered arrays of myosin
• Striated appearance due to sarcomeres (basic
  functional unit)

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Muscle Contractions Sliding-Filament Model

• Thin and thick filaments of the sarcomere slide
  past one another to shorten the length of the
  muscle

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Muscle Contractions

• Motor Unit A single nerve ending and all the
  muscle fibers attached to it
• With a nerve impulse- muscle fibers contract
  completely. all or none- the amt. of fibers
  contracting can vary!
• Does a muscle have to contract completely?
• Partial contraction of a muscle comes from only
  contracting a portion of the fibers (see above)

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• Calcium is the so called "trigger" for muscle
  contraction. Calcium aids in the formation of
  action potential in the motor end plate, and is
  later released from the terminal cisternae of the
  sarcoplasmic reticulum into the cytosol of a
  striated (cardiac and skeletal) muscle cells.
  Next the calcium ions bind to troponin which
  causes a change in the conformation of the
  troponin-tropomyosin complex that exposes the
  myosin binding sites on the actin filament. The
  myosin heads then attach to the actin filament
  and a muscle contraction occurs.

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• Chemical energy in muscle fibers is in the form
  of ATP. In order to produce physical energy, ATP
  is hydrolyzed to become ADP and Pi (adenosine
  diphosphate and inorganic phosphate). When ATP is
  broken down into ADP and Pi the cross bridges are
  energized which allows for the "power stroke", or
  force production of a muscle contraction.
• Source http//www.cartage.org.lb/en/themes/scien
  ces/zoology/animalphysiology/muscles/muscles.htm

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Microscopic Anatomy of Muscle

• Sliding Filaments when the muscles are
  triggered by motor nerve cells, impulses travel
  down the T-tubule of the sarcomere (see following
  picture).
• Calcium is then released from the sarcoplasmic
  reticulum. This causes the sarcomere to shorten.
  The actin slides across the myosin. ATP
  provides the power for this contraction.

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Fig. 7.3a
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Fig. 7.5
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Connective coverings

• Muscles are covered with fascia (dense regular
  connective) which separates muscles. Deep fascia
  separates muscles from each other, superficial
  fascia-from skin.
• Fascia are continuous with tendons which are
  continuous with the bone periosteum.

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Smaller picture

• Muscles are grouped in to fascicles that are
  covered with a sheath of connective tissue called
  perimysium.
• Fascicles are divided into muscle fibers, each
  surrounded by the endomysium
• Blood and nerves reach the muscle through the
  endomysium

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Exercise

• Atrophy- from lack of use, muscle fibers are
  replaced with adipose and fibrous tissue
• Can cause muscle fibers to shorten enough to
  force the body to contort.
• Hypertrophy-more myofibrils develop with more use

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Going the Distance, or not?

• Slow twitch- less fibers per motor unit- better
  for endurance sports
• Largely aerobic-extra mitochondria, extra
  capillaries
• Presence of Myoglobin
• A dark, red oxygen carrying pigment
• Fast Twitch- more fibers per motor unit- better
  for powerful, short muscle bursts
• Few mitochondria
• Largley anerobic
• Easily hits maximum tension

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Macroscopic Anatomy of Muscle

• 3 Layers of connective tissue are part of each
  muscle
• Epimysium surrounds entire muscle, dense layer
  of collagen fibers.
• Perimysium divides muscle into compartments
  called fascicles.
• Endomysium delicate connective tissue that
  surrounds each muscle cell or fiber.
• Where these connective tissues run together at
  the end of muscles they form tendons or
  aponeurosis.

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Fig. 7.2a
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Fig. 7.9
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Fig. 7.10
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Fig. 7.10a
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Fig. 7.10b
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Fig. 7.11
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Fig. 7.12
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Table 7.1