1. Chapter 5 The Skeletal System

2. The Skeletal System 4 Parts of the skeletal system Bones (skeleton)
Joints
Cartilages
Ligaments -bone to bone and Tendon-bone to muscle
Divided into two divisions
Axial skeleton - torso
Appendicular skeleton – limbs and girdle
Slide 5.1
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4. Functions of Bones Support of the body-provides a framework
Protection of soft organs-spinal cord, heart, etc.
Movement due to attached skeletal muscles- for walking, breathing
Storage of minerals and fats- calcium and phosphate
Blood cell formation- in the marrow of long bones
Slide 5.2
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5. Bones of the Human Body The skeleton has 206 bones
Two basic types of bone tissue
Compact bone
Homogeneous
External layer
Spongy bone
Also called cancellous bone
Needle-like pieces are called trabeculae
Figure 5.2b
Slide 5.3
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6. Classification of Bones
Long bones
Typically longer than wide
Have a shaft with heads at both ends
Contain mostly compact bone
Examples: Femur, humerus
Slide 5.4a
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7. Classification of Bones
Short bones
Generally cube-shape
Contain mostly spongy bone
Examples: Carpals, tarsals
Slide 5.4b
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8. Classification of Bones on the Basis of Shape
Figure 5.1
Slide 5.4c
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9. Classification of Bones
Flat bones
Thin and flattened
Usually curved
Thin layers of compact bone around a layer of spongy bone
Examples: Skull, ribs, sternum
Slide 5.5a
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10. Classification of Bones
Irregular bones
Irregular shape
Do not fit into other bone classification categories
Example: Vertebrae and hip
Slide 5.5b
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11. Classification of Bones on the Basis of Shape
Figure 5.1
Slide 5.5c
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12. Gross Anatomy of a Long Bone
Diaphysis
Shaft, or long axis
Composed of compact bone
Center is medullary canal
Epiphysis
Ends of the bone
Composed mostly of spongy bone
Medullary Canal
Also called the marrow cavity
Composed mostly of yellow fat (Adipose) in adults
Use for reserves
Figure 5.2a
Slide 5.6
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13. Structures of a Long Bone
Periosteum
Protective outer covering of the diaphysis
Fibrous connective tissue membrane
Consists of dense irregular CT and osteoblasts/osteoclasts
Sharpey’s fibers
Secure periosteum to underlying bone
Arteries
Supply bone cells with nutrients
Transport RBC out to body
Figure 5.2c
Slide 5.7
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14. Structures of a Long Bone
Articular cartilage
Covers the external surface of the epiphyses
Made of hyaline cartilage
Decreases friction at joint surfaces during movement
Epiphyseal Line
The line is the remnant of the epiphyseal plate, a disc of cartilage that grows during childhood to lengthen the bone.
Figure 5.2a
Slide 5.8a
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15. Chemical Composition of Bones
Organic Components
Cells (osteoblasts, clasts, cytes)
Osteoid ( ground substance and collagen)
Slide 5.8a
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16. Chemical Composition of Bones
Inorganic Components
Hydroxyapatites (Mineral Salts)
Calcium phosphate
Form tiny crystals that lie around the collagen fibers
Healthy bone is ½ as strong as steel!
Slide 5.8b
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17. Microscopic Anatomy of Bone
Osteon are also called Haversian Systems.
They are a unit of bone
Central canal is also called a Haversian canal
Opening in the center of an osteon
Carries blood vessels and nerves to bone cells
Perforating (Volkman’s) canal
Canal perpendicular to the central canal
Slide 5.10a
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18. Microscopic Anatomy of Bone
Figure 5.3
Slide 5.10b
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19. Microscopic Anatomy of Bone
Lacunae
Cavities (holes) containing bone cells (called osteocytes)
Arranged in concentric (circular) rings
Lamellae
Rings around the central canal
Sites of lacunae
Figure 5.3
Slide 5.11a
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20. Microscopic Anatomy of Bone
Canaliculi
Tiny canals
Radiate from the central canal to lacunae
Form a transport system for blood and nutrients
Figure 5.3
Slide 5.11b
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21. Changes in the Human Skeleton
In embryos, the skeleton is primarily hyaline cartilage
During development, much of this cartilage is replaced by bone
Cartilage remains in isolated areas
Bridge of the nose
Parts of ribs
Joints
Slide 5.12
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22. Bone Growth
Epiphyseal plates allow for growth of long bone during childhood
New cartilage is continuously formed
Older cartilage becomes ossified
Cartilage is broken down
Bone replaces cartilage
Slide 5.13a
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23. Bone Growth Bones are remodeled and lengthened until growth stops
Bones change shape somewhat
Bones grow in width
Slide 5.13b
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24. Long Bone Formation and Growth
Figure 5.4a
Slide 5.14a
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25. Types of Bone Cells Osteocytes Osteoblasts Osteoclasts
Mature bone cells
Osteoblasts
Bone-forming cells
Osteoclasts
Bone-destroying cells
Break down bone matrix for remodeling and release of calcium
Bone remodeling is a process by both osteoblasts and osteoclasts
Slide 5.15
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26. Bone Fractures A break in a bone Types of bone fractures
Closed (simple) fracture – break that does not penetrate the skin
Open (compound) fracture – broken bone penetrates through the skin
Bone fractures are treated by reduction and immobilization
Realignment of the bone
Slide 5.16
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27. Bone Fractures Cont… Nondisplaced fractures
Bones retain their normal position
Displaced fractures
Ends are out of their normal position
Complete fracture
The bone is broken through
Incomplete
The bone is not broken through
Transverse
Break is perpendicular to the bone’s long axis
Linear
Break is parallel to the long axis
Slide 5.15
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28. Common Types of Fractures
Table 5.2
Slide 5.17
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29. Repair of Bone Fractures
Hematoma (blood-filled swelling) is formed
Break is splinted by fibrocartilage to form a callus
Fibrocartilage callus is replaced by a bony callus
Bony callus is remodeled to form a permanent patch
Slide 5.18
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30. Stages in the Healing of a Bone Fracture
Figure 5.5
Slide 5.19
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31. Paranasal Sinuses
Hollow portions of bones surrounding the nasal cavity
Figure 5.10
Slide 5.25a
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32. Paranasal Sinuses Functions of paranasal sinuses Lighten the skull
Give resonance and amplification to voice
Figure 5.10
Slide 5.25b
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33. The Hyoid Bone
The only bone that does not articulate with another bone
Serves as a moveable base for the tongue
Figure 5.12
Slide 5.26
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34. The Fetal Skull
The fetal skull is large compared to the infants total body length
Figure 5.13
Slide 5.27a
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35. The Fetal Skull
Fontanelles – fibrous membranes connecting the cranial bones
Allow the brain to grow
Convert to bone within 24 months after birth
Figure 5.13
Slide 5.27b
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36. The Vertebral Column Vertebrae separated by intervertebral discs
The spine has a normal curvature
Each vertebrae is given a name according to its location
Figure 5.14
Slide 5.28
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37. Structure of a Typical Vertebrae
Figure 5.16
Slide 5.29
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38. Bones of the Upper Limb The hand Carpals – wrist Metacarpals – palm
Phalanges – fingers
Figure 5.22
Slide 5.36
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39. Gender Differences of the Pelvis
Figure 5.23c
Slide 5.39
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40. Bones of the Lower Limbs
The foot
Tarsus – ankle
Metatarsals – sole
Phalanges – toes
Figure 5.25
Slide 5.41
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41. Joints Articulations of bones Functions of joints
Hold bones together
Allow for mobility
Ways joints are classified
Functionally
Structurally
Slide 5.43
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42. Types of Synovial Joints Based on Shape
Figure 5.29a–c
Slide 5.52a
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43. Types of Synovial Joints Based on Shape
Figure 5.29d–f
Slide 5.52b
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44. Inflammatory Conditions Associated with Joints
Bursitis – inflammation of a bursa usually caused by a blow or friction
Tendonitis – inflammation of tendon sheaths
Arthritis – inflammatory or degenerative diseases of joints
Over 100 different types
The most widespread crippling disease in the United States
Slide 5.53
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45. Clinical Forms of Arthritis
Osteoarthritis
Most common chronic arthritis
Probably related to normal aging processes
Rheumatoid arthritis
An autoimmune disease – the immune system attacks the joints
Symptoms begin with bilateral inflammation of certain joints
Often leads to deformities
Slide 5.54a
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48. Clinical Forms of Arthritis
Gouty Arthritis
Inflammation of joints is caused by a deposition of urate crystals from the blood
Can usually be controlled with diet
Slide 5.54b
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