PowerLecture: Chapter 5

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PowerLectureChapter 5

• The Skeletal System

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Learning Objectives

• List the functions of bone.
• Identify human bones by name and location.
• Identify the locations and types of joints.
• Characterize several common disorders associated
  with the skeletal system.

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Impacts/Issues

• Creaky Joints

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Creaky Joints

• Many people currently suffer, or may one day
  suffer, from osteoarthritis, in which the joints
  between bones become stiff and painful due to the
  degeneration of the cartilage lining.
• Conventional remedies range from pain relievers
  to supplements to injections of steroids.
• More unconventional treatments employ
  combinations of various botanical extracts.

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Creaky Joints

• Arthritis is a disorder of the skeletal system,
  the framework of bone, cartilage, and ligaments
  on which the body is built.

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How Would You Vote?

• To conduct an instant in-class survey using a
  classroom response system, access JoinIn Clicker
  Content from the PowerLecture main menu.
• Should claims about medicinal exotic plant
  extracts have to be backed up by independent
  scientific testing?
• a. Yes, or companies could make any claim about
  their product.
• b. No, so long as the extract does no harm, let
  the buyer decide what to buy.

7
Section 1

• BoneMineralized Connective Tissue

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Bone Mineralized Connective Tissue

• Bone is a connective tissue with living cells
  (osteocytes) and collagen fibers distributed
  throughout a ground substance that is hardened
  by calcium salts.
• As bone develops, precursor cells called
  osteoblasts secrete collagen fibers and a ground
  substance of proteins and carbohydrates.
• Eventually, osteocytes reside within lacunae in
  the ground substance, which becomes mineralized
  by calcium deposits.

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Bone Mineralized Connective Tissue

• Bones are surrounded by a sturdy membrane called
  the periosteum.
• There are two kinds of bone tissue.
• Compact bone tissue forms the bones shaft and
  the outer portion of its two ends.
• Compact bone forms in thin, circular layers
  (osteons or Haversian systems) with small canals
  at their centers, which contain blood vessels and
  nerves.
• Osteocytes in the lacunae communicate by way of
  canaliculi (little canals).
• Spongy bone tissue is located inside the shaft of
  long bones.

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Fig. 5.1, p. 88
space occupied by living bone cell
blood vessel
compact bone tissue
spongy bone tissue
osteon (Haversian system)
spongy bone tissue
compact bone tissue
outer layer of dense connective tissue
blood vessel
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Animation Structure of the Human Thigh Bone
CLICKTO PLAY
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Bone Mineralized Connective Tissue

• A bone develops on a cartilage model.
• Osteoblasts secrete material inside the shaft of
  the cartilage model of long bones.
• Calcium is deposited cavities merge to form the
  marrow cavity.
• Eventually osteoblasts become trapped within
  their own secretions and become osteocytes
  (mature bone cells).

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Bone Mineralized Connective Tissue

• In growing children, the epiphyses (ends of bone)
  are separated from the shaft by an epiphyseal
  plate (cartilage), which continues to grow under
  the influence of growth hormone until late
  adolescence.

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Fig. 5.2, p. 89
Stepped Art
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Animation How a Long Bone Forms
CLICKTO PLAY
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Bone Mineralized Connective Tissue

• Bone tissue is constantly remodeled.
• Bone is renewed constantly as minerals are
  deposited by osteoblasts and withdrawn by
  osteoclasts during the bone remodeling process.
• Before adulthood, bone turnover is especially
  important in increasing the diameter of certain
  bones.
• Bone turnover helps to maintain calcium levels
  for the entire body.

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Bone Mineralized Connective Tissue

• A hormone called PTH causes bone cells to release
  enzymes that will dissolve bone tissue and
  release calcium to the interstitial fluid and
  blood calcitonin stimulates the reverse.
• Osteoporosis (decreased bone density) is
  associated with decreases in osteoblast activity,
  sex hormone production, exercise, and calcium
  uptake.

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Fig. 5.3, p. 89
a
b
19
Video Taller and Taller
CLICKTO PLAY

• From ABC News, Human Biology in the Headlines,
  2006 DVD.

20
Section 2

• The Skeleton The Bodys Bony Framework

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The Skeleton The Bodys Bony Framework

• Bones are the main components of the human
  skeletal system.
• There are four types of bones long (arms), short
  (ankle), flat (skull), and irregular (vertebrae).
• Bone marrow fills the cavities of bones.
• In long bones, red marrow is confined to the
  ends yellow marrow fills the shaft portion.
• Irregular bones and flat bones are completely
  filled with the red bone marrow responsible for
  blood cell formation.

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The Skeleton The Bodys Bony Framework

• The skeleton a preview.
• The 206 bones of a human are arranged in two
  major divisions the axial skeleton and the
  appendicular skeleton.
• Bones are attached to other bones by ligaments
  bones are connected to muscles by tendons.

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The Skeleton The Bodys Bony Framework

• Bone functions are vital in maintaining
  homeostasis.
• The bones are moved by muscles thus the whole
  body is movable.
• The bones support and anchor muscles.
• Bones protect vital organs such as the brain and
  lungs.
• Bone tissue acts as a depository for calcium,
  phosphorus, and other ions.
• Parts of some bones are sites of blood cell
  production.

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Table 5.1, p. 90
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Section 3

• The Axial Skeleton

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The Axial Skeleton

• The skull protects the brain.
• The skull consists of more than two dozen bones.
• The cranial vault, or brain case, is a grouping
  of eight bones.
• The frontal bone makes up the forehead and
  contains the sinuses.
• Temporal bones form the lower sides of the
  cranium and surround the ear canals.
• A sphenoid bone and an ethmoid bone form the eye
  socket.

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frontal sinus
sphenoid sinus
ethmoid sinus
maxillary sinus
Fig. 5.6c, p. 93
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The Axial Skeleton

• Parietal bones form a large part of the skull
  above the temporal bones.
• An occipital bone forms the back of the skull and
  encloses the foramen magnum, which is a
  passageway for the spinal cord.

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Fig. 5.6a, p. 92
frontal bone
parietal bone
sphenoid bone
ethmoid bone
temporal bone
lacrimal bone
zygomatic bone
maxilla
occipital bone
external auditory meatus (opening of the ear
part of the temporal bone)
mandible
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The Axial Skeleton

• Facial bones support and shape the face.
• A mandible forms the lower jaw two maxillary
  bones form the upper jaw.
• Zygomatic bones form the cheekbones lacrimal
  bones form the inner eye sockets.
• Palatine bones make up
• the nasal cavity a vomer
• bone forms the nasal
• septum.

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Fig. 5.6b, p. 92
maxilla
hard palate
maxilla
palatine bone
zygomatic bone
vomer
sphenoid bone
jugular foramen
temporal bone
foramen magnum
parietal bone
occipital bone
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The Axial Skeleton

• The vertebral column is the backbone.
• The vertebral column, or backbone, extends from
  the base of the skull to the hipbones.
• The spinal cord extends through a cavity formed
  by the vertebrae.
• Humans have 33 vertebrae 7 cervical, 12
  thoracic, and 5 lumbar, plus a sacrum formed of 5
  fused vertebrae and a coccyx of 4 fused
  vertebrae.
• Fibrocartilaginous intervertebral disks serve as
  shock absorbers they may slip (herniate) or
  rupture, leading to pain and immobility.

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The Vertebral Column
Figure 5.7
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Fig. 5.7, p. 93
1
2
cervical vertebrae (7)
3
4
5
6
7
1
2
3
4
5
6
thoracic vertebrae (12)
7
8
9
10
11
12
1
2
intervertebral disks
lumbar vertebrae (5)
3
4
5
sacrum (5 fused)
coccyx (4 fused)
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The Axial Skeleton

• The ribs and sternum support and help protect
  internal organs.
• Ribs (12 pairs) are attached to the vertebrae
  dorsally and serve as scaffolding for the upper
  body torso.
• Most of the ribs are attached to the sternum
  ventrally.

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Animation Axial Skeleton
CLICKTO PLAY
37
Video Painful Painkillers
CLICKTO PLAY

• From ABC News, Human Biology in the Headlines,
  2006 DVD.

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Section 4

• The Appendicular Skeleton

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The Appendicular Skeleton

• The pectoral girdle and upper limbs provide
  flexibility.
• The pectoral girdle includes the bones of, and is
  attached to, the shoulder.
• The scapula is a large, flat shoulder blade with
  a socket for the upper arm bone.
• The clavicle (collarbone) connects the scapula to
  the sternum.

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The Appendicular Skeleton

• Each upper limb includes some 30 separate bones.
• The humerus is the bone of the upper arm.
• The radius and ulna extend from the hingelike
  joint of the elbow to the wrist.
• The carpals form the wrist the metacarpals form
  the palm of the hand, and the phalanges the
  fingers.

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Fig. 5.8, p. 94
clavicle
humerus
sternum
scapula
ulna
radius
carpals (8)
metacarpals (5)
phalanges (14)
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The Appendicular Skeleton

• The pelvic girdle and lower limbs support body
  weight.
• The pelvic girdle includes the pelvis and the
  legs.
• The pelvis is made up of coxal bones attaching to
  the sacrum in the back and forming the pelvic
  arch in the front.
• The pelvis is broader in females than males this
  is necessary for childbearing.

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The Appendicular Skeleton

• The legs contain the bodys largest bones.
• The femur is the longest bone, extending from the
  pelvis to the knee.
• The tibia and fibula form
• the lower leg the kneecap
• bone is the patella.
• Tarsal bones compose the ankle, metatarsals the
  foot, and phalanges the toes.

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Fig. 5.4, p. 90
nutrient canal into and from marrow (for blood
vessels and nerves)
marrow cavity
compact bone tissue
spongy bone tissue
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Fig. 5.9, p. 95
pelvis
sacrum
femur
pubic symphysis
patella
tibia
fibula
metatarsals
phalanges
tarsals
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Animation Appendicular Skeleton
CLICKTO PLAY
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Fig. 5.5, p. 91
Skull bones
Pectoral girdle and upperlimb bones
cranial bones
clavicle
facial bones
Rib cage
scapula
sternum
humerus
ribs
radius
ulna
Vertebral column (backbone)
vertebrae
phalanges
carpals
intervertebral disks
metacarpals
Pelvic girdle and lowerlimb bones
pelvic girdle
femur
patella
tibia
ligament bridging a knee joint, here sliced down
through the middle, side view.
fibula
tarsals
metatarsals
AXIAL SKELETON
phalanges
APPENDICULAR SKELETON
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Animation The Human Skeleton System
CLICKTO PLAY
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Section 5

• JointsConnections Between Bones

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Joints Connections Between Bones

• Synovial joints move freely.
• Synovial joints are the most common type of joint
  and move freely they include the ball-and-socket
  joints of the hips and the hingelike joints such
  as the knee.
• These types of joints are stabilized by
  ligaments.
• A capsule of dense connective tissue surrounds
  the bones of the joint and produces synovial
  fluid that lubricates the joint.

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Fig. 5.10a, p. 96
femur
ligament
posterior cruciate ligament
meniscus
anterior cruciate ligament
ligament
ligament (cut)
fibula
tibia
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Fig. 5.10b, p. 96
quadriceps (straightens leg)
biceps femoris (bends leg)
tendon (to thigh muscle)

femur


knee cap (patella)
cartilage

ligament

ligament (to knee cap)
tibia
fibula
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Fig. 5.11a (1), p. 97
flexion at shoulder
extension at shoulder
flexion at knee
extension at knee
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Fig. 5.11a (2), p. 97
hyperextension
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Fig. 5.11b, p. 97
circumduction
rotation
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Fig. 5.11c, p. 97
abduction
adduction
abduction
abduction
adduction
adduction
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Fig. 5.11d, p. 97
supination
pronation
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Fig. 5.11e, p. 97
gliding movement between carpals
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Joints Connections Between Bones

• Other joints move little or not at all.
• Cartilaginous joints (such as between the
  vertebrae) have no gap, but are held together by
  cartilage and can move only a little.
• Fibrous joints also have no gap between the bones
  and hardly move flat cranial bones are an
  example.

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intervertebral disks
In-text Fig., p. 96
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Section 6

• Disorders of the Skeleton

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Disorders of the Skeleton

• Inflammation is a factor in some skeletal
  disorders.
• In rheumatoid arthritis, the synovial membrane
  becomes inflamed due to immune system
  dysfunction, the cartilage degenerates, and bone
  is deposited into the joint.

Figure 5.12
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Disorders of the Skeleton

• In osteoarthritis, the cartilage at the end of
  the bone degenerates.
• Tendinitis is the inflammation of tendons and
  synovial membranes around joints.
• Carpal tunnel syndrome is the result of the
  inflammation of the tendons in the space between
  a wrist ligament and the carpal bones, usually
  aggravated by chronic over use.

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Disorders of the Skeleton

• Joints also are vulnerable to strains, sprains,
  and dislocations.
• A strain results from stretching or twisting a
  joint suddenly or too far.
• A sprain is a tear of ligaments or tendons.
• A dislocation causes two bones to no longer be in
  contact.

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Disorders of the Skeleton

• In factures, bones break.
• A simple fracture is a crack in the bone not
  very serious.
• A complete fracture separates the bone into two
  pieces, which must be quickly realigned for
  proper healing.
• A compound fracture is the most serious because
  it means there are multiple breaks with the
  possibility of bone fragments penetrating the
  surrounding tissues.

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simple
compound
complete
Fig. 5.13, p. 98
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Disorders of the Skeleton

• Other bone disorders include genetic diseases,
  infections, and cancer.
• Genetic diseases such as osteogenesis imperfecta
  can leave bones brittle and easily broken.

Figure 5.14
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Disorders of the Skeleton

• Bacterial and other infections can spread from
  the blood stream to bone tissue or marrow.
• Osteosarcoma, bone cancer, usually occurs in long
  bones.

Figure 5.15
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Table 5.2, p. 100