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2 Support and Movement Fundamentals of Anatomy & Physiology Unit

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1 2 Support and Movement Fundamentals of Anatomy & Physiology Unit
Frederic H. Martini PowerPoint® Lecture Slides prepared by Professor Albia Dugger, Miami–Dade College, Miami, FL Professor Robert R. Speed, Ph.D., Wallace Community College, Dothan, AL Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

2 Chapter 6: Osseous Tissue and Bone Structure

3 The Skeletal System Skeletal system includes: bones of the skeleton
cartilages, ligaments, and connective tissues

4 What are the functions of the skeletal system?

5 Functions of the Skeletal System
Support Storage of minerals (calcium) Storage of lipids (yellow marrow)

6 Functions of the Skeletal System
Blood cell production (red marrow) Protection Leverage (force of motion)

7 How are bones classified?

8 Classification of Bones
Bones are identified by: shape internal tissues bone markings

9 Bone Shapes Long bones Flat bones Sutural bones Irregular bones
Short bones Sesamoid bones

10 Long Bones Figure 6–1a

11 Long Bones Are long and thin
Are found in arms, legs, hands, feet, fingers, and toes

12 Flat Bones Figure 6–1b

13 Flat Bones Are thin with parallel surfaces
Are found in the skull, sternum, ribs, and scapula

14 Sutural Bones Figure 6–1c

15 Sutural Bones Are small, irregular bones
Are found between the flat bones of the skull

16 Irregular Bones Figure 6–1d

17 Irregular Bones Have complex shapes Examples: spinal vertebrae
pelvic bones

18 Short Bones Figure 6–1e

19 Short Bones Are small and thick Examples: ankle wrist bones

20 Sesamoid Bones Figure 6–1f

21 Sesamoid Bones Are small and flat
Develop inside tendons near joints of knees, hands, and feet

22 Bone Markings Depressions or grooves: Projections: Tunnels:
along bone surface Projections: where tendons and ligaments attach at articulations with other bones Tunnels: where blood and nerves enter bone

23 Bone Markings Table 6–1 (1 of 2)

24 Bone Markings Table 6–1 (2 of 2)

25 Long Bones The femur Figure 6–2a

26 Long Bones Diaphysis: Epiphysis: Metaphysis: the shaft
wide part at each end articulation with other bones Metaphysis: where diaphysis and epiphysis meet

27 The Diaphysis A heavy wall of compact bone, or dense bone
A central space called marrow cavity

28 The Epiphysis Mostly spongy (cancellous) bone
Covered with compact bone (cortex)

29 Flat Bones The parietal bone of the skull Figure 6–2b

30 Flat Bones Resembles a sandwich of spongy bone
Between 2 layers of compact bone

31 What are the types and functions of bone cells?

32 Bone (Osseous) Tissue Dense, supportive connective tissue
Contains specialized cells Produces solid matrix of calcium salt deposits Around collagen fibers

33 Characteristics of Bone Tissue
Dense matrix, containing: deposits of calcium salts bone cells within lacunae organized around blood vessels

34 Characteristics of Bone Tissue
Canaliculi: form pathways for blood vessels exchange nutrients and wastes

35 Characteristics of Bone Tissue
Periosteum: covers outer surfaces of bones consist of outer fibrous and inner cellular layers

36 Matrix Minerals 2/3 of bone matrix is calcium phosphate, Ca3(PO4)2:
reacts with calcium hydroxide, Ca(OH)2 to form crystals of hydroxyapatite, Ca10(PO4)6(OH)2 which incorporates other calcium salts and ions

37 Matrix Proteins 1/3 of bone matrix is protein fibers (collagen)

38 Bone Cells Make up only 2% of bone mass: osteocytes osteoblasts
osteoprogenitor cells osteoclasts

39 Osteocytes Mature bone cells that maintain the bone matrix
Figure 6–3 (1 of 4)

40 Osteocytes Live in lacunae Are between layers (lamellae) of matrix
Connect by cytoplasmic extensions through canaliculi in lamellae Do not divide

41 Osteocyte Functions To maintain protein and mineral content of matrix
To help repair damaged bone

42 Osteoblasts Immature bone cells that secrete matrix compounds (osteogenesis) Figure 6–3 (2 of 4)

43 Osteoid Matrix produced by osteoblasts, but not yet calcified to form bone Osteoblasts surrounded by bone become osteocytes

44 Osteoprogenitor Cells
Mesenchymal stem cells that divide to produce osteoblasts Figure 6–3 (3 of 4)

45 Osteoprogenitor Cells
Are located in inner, cellular layer of periosteum (endosteum) The endosteum is a thin layer of connective tissue which lines the surface of the bony tissue that forms the medullary cavity of long bones. This endosteal surface is usually resorbed during long periods of malnutrition Assist in fracture repair

46 Osteoclasts Secrete acids and protein-digesting enzymes
Figure 6–3 (4 of 4)

47 Osteoclasts Giant, mutlinucleate cells
Dissolve bone matrix and release stored minerals (osteolysis) Are derived from stem cells that produce macrophages

48 Homeostasis Bone building (by osteoblasts) and bone recycling (by osteoclasts) must balance: more breakdown than building, bones become weak exercise causes osteocytes to build bone

49 What is the difference between compact bone and spongy bone?

50 Compact Bone Figure 6–5

51 Osteon The basic (smallest) unit of mature compact bone
Osteocytes are arranged in concentric lamellae Around a central canal containing blood vessels

52 Perforating Canals Perpendicular to the central canal
Carry blood vessels into bone and marrow

53 Circumferential Lamellae
Lamellae wrapped around the long bone Binds osteons together

54 Spongy Bone Figure 6–6

55 Spongy Bone Does not have osteons
The matrix forms an open network of trabeculae Trabeculae have no blood vessels

56 Red Marrow The space between trabeculae is filled with red bone marrow: which has blood vessels forms red blood cells and supplies nutrients to osteocytes

57 Yellow Marrow In some bones, spongy bone holds yellow bone marrow:
is yellow because it stores fat

58 Weight–Bearing Bones Figure 6–7

59 Weight–Bearing Bones The femur transfers weight from hip joint to knee joint: causing tension on the lateral side of the shaft and compression on the medial side

60 Periosteum and Endosteum
Compact bone is covered with membrane: periosteum on the outside endosteum on the inside

61 Periosteum Figure 6–8a

62 Periosteum Covers all bones: It is made up of:
except parts enclosed in joint capsules It is made up of: an outer, fibrous layer and an inner, cellular layer

63 Perforating Fibers Collagen fibers of the periosteum:
connect with collagen fibers in bone and with fibers of joint capsules, attached tendons, and ligaments

64 Functions of Periosteum
Isolate bone from surrounding tissues Provide a route for circulatory and nervous supply Participate in bone growth and repair

65 Endosteum Figure 6–8b

66 Endosteum An incomplete cellular layer: lines the marrow cavity
covers trabeculae of spongy bone lines central canals

67 Endosteum Contains osteoblasts, osteoprogenitor cells, and osteoclasts
Is active in bone growth and repair

68 What is the difference between intramembranous ossification and endochondral ossification?

69 Bone Development Human bones grow until about age 25 Osteogenesis:
bone formation Ossification: the process of replacing other tissues with bone

70 Calcification The process of depositing calcium salts
Occurs during bone ossification and in other tissues

71 Ossification The 2 main forms of ossification are:
intramembranous ossification endochondral ossification

72 Intramembranous Ossification
Also called dermal ossification: because it occurs in the dermis produces dermal bones such as mandible and clavicle There are 3 main steps in intramembranous ossification

73 Intramembranous Ossification: Step 1
Figure 6–11 (Step 1)

74 Intramembranous Ossification: Step 1
Mesenchymal cells aggregate: differentiate into osteoblasts begin ossification at the ossification center develop projections called spicules

75 Intramembranous Ossification: Step 2
Figure 6–11 (Step 2)

76 Intramembranous Ossification: Step 2
Blood vessels grow into the area: to supply the osteoblasts Spicules connect: trapping blood vessels inside bone

77 Intramembranous Ossification: Step 3
Figure 6–11 (Step 3)

78 Intramembranous Ossification: Step 3
Spongy bone develops and is remodeled into: osteons of compact bone periosteum or marrow cavities

79 Endochondral Ossification
Ossifies bones that originate as hyaline cartilage Most bones originate as hyaline cartilage

80 How does bone form and grow?

81 Endochondral Ossification
Growth and ossification of long bones occurs in 6 steps

82 Endochondral Ossification: Step 1
Chondrocytes in the center of hyaline cartilage: enlarge form struts and calcify die, leaving cavities in cartilage Figure 6–9 (Step 1)

83 Endochondral Ossification: Step 2
Figure 6–9 (Step 2)

84 Endochondral Ossification: Step 2
Blood vessels grow around the edges of the cartilage Cells in the perichondrium change to osteoblasts: producing a layer of superficial bone around the shaft which will continue to grow and become compact bone (appositional growth)

85 Endochondral Ossification: Step 3
Blood vessels enter the cartilage: bringing fibroblasts that become osteoblasts spongy bone develops at the primary ossification center Figure 6–9 (Step 3)

86 Endochondral Ossification: Step 4
Remodeling creates a marrow cavity: bone replaces cartilage at the metaphyses Figure 6–9 (Step 4)

87 Endochondral Ossification: Step 5
Capillaries and osteoblasts enter the epiphyses: creating secondary ossification centers Figure 6–9 (Step 5)

88 Endochondral Ossification: Step 6
Figure 6–9 (Step 6)

89 Endochondral Ossification: Step 6
Epiphyses fill with spongy bone: cartilage within the joint cavity is articulation cartilage cartilage at the metaphysis is epiphyseal cartilage

90 Endochondral Ossification
Appositional growth: compact bone thickens and strengthens long bone with layers of circumferential lamellae PLAY Endochondral Ossification Figure 6–9 (Step 2)

91 What are the characteristics of adult bones?

92 Epiphyseal Lines Figure 6–10

93 Epiphyseal Lines When long bone stops growing, after puberty:
epiphyseal cartilage disappears is visible on X-rays as an epiphyseal line

94 Mature Bones As long bone matures: osteoclasts enlarge marrow cavity
osteons form around blood vessels in compact bone

95 Blood Supply of Mature Bones
3 major sets of blood vessels develop Figure 6–12

96 Blood Vessels of Mature Bones
Nutrient artery and vein: a single pair of large blood vessels enter the diaphysis through the nutrient foramen femur has more than 1 pair

97 Blood Vessels of Mature Bones
Metaphyseal vessels: supply the epiphyseal cartilage where bone growth occurs

98 Blood Vessels of Mature Bones
Periosteal vessels provide: blood to superficial osteons secondary ossification centers

99 Lymph and Nerves The periosteum also contains:
networks of lymphatic vessels sensory nerves

100 How does the skeletal system remodel and maintain homeostasis, and what are the effects of nutrition, hormones, exercise, and aging on bone?

101 Remodeling The adult skeleton: Remodeling: maintains itself
replaces mineral reserves Remodeling: recycles and renews bone matrix involves osteocytes, osteoblasts, and osteoclasts

102 KEY CONCEPTS Bone continually remodels, recycles, and replaces
Turnover rate varies If deposition is greater than removal, bones get stronger If removal is faster than replacement, bones get weaker

103 Effects of Exercise on Bone
Mineral recycling allows bones to adapt to stress Heavily stressed bones become thicker and stronger

104 Bone Degeneration Bone degenerates quickly
Up to 1/3 of bone mass can be lost in a few weeks of inactivity

105 KEY CONCEPTS What you don’t use, you lose
Stresses applied to bones during physical activity are essential to maintain bone strength and mass

106 Effects of Hormones and Nutrition on Bone
Normal bone growth and maintenance requires nutritional and hormonal factors

107 Minerals A dietary source of calcium and phosphate salts:
plus small amounts of magnesium, fluoride, iron, and manganese

108 Calcitriol The hormone calcitriol: is made in the kidneys
helps absorb calcium and phosphorus from digestive tract synthesis requires vitamin D3 (cholecalciferol)

109 Vitamins Vitamin C is required for collagen synthesis, and stimulates osteoblast differentiation Vitamin A stimulates osteoblast activity Vitamins K and B12 help synthesize bone proteins

110 Other Hormones Growth hormone and thyroxine stimulate bone growth
Estrogens and androgens stimulate osteoblasts Calcitonin and parathyroid hormone regulate calcium and phosphate levels

111 Hormones for Bone Growth and Maintenance
Table 6–2

112 The Skeleton as Calcium Reserve
Bones store calcium and other minerals Calcium is the most abundant mineral in the body

113 Chemical Composition of Bone
Figure 6–13

114 Functions of Calcium Calcium ions are vital to: membranes neurons
muscle cells, especially heart cells

115 Calcium Regulation Calcium ions in body fluids:
must be closely regulated Homeostasis is maintained: by calcitonin and parathyroid hormone which control storage, absorption, and excretion

116 Calcitonin and Parathyroid Hormone Control
Bones: where calcium is stored Digestive tract: where calcium is absorbed Kidneys: where calcium is excreted

117 Parathyroid Hormone (PTH)
Figure 6–14a

118 Parathyroid Hormone (PTH)
Produced by parathyroid glands in neck Increases calcium ion levels by: stimulating osteoclasts increasing intestinal absorption of calcium decreases calcium excretion at kidneys

119 Calcitonin Figure 6–14b

120 Calcitonin Secreted by C cells (parafollicular cells) in thyroid
Decreases calcium ion levels by: inhibiting osteoclast activity increasing calcium excretion at kidneys

121 KEY CONCEPTS Calcium and phosphate ions in blood are lost in urine
Ions must be replaced to maintain homeostasis If not obtained from diet, ions are removed from the skeleton, weakening bones Exercise and nutrition keep bones strong

122 What are the types of fractures, and how do they heal?

123 Fractures Fractures: Fractures are repaired in 4 steps
cracks or breaks in bones caused by physical stress Fractures are repaired in 4 steps

124 Fracture Repair: Step 1 Figure 6–15 (Step 1)

125 Fracture Repair: Step 1 Bleeding: Bone cells in the area die
produces a clot (fracture hematoma) establishes a fibrous network Bone cells in the area die

126 Fracture Repair: Step 2 Figure 6–15 (Step 2)

127 Fracture Repair: Step 2 Cells of the endosteum and periosteum:
Divide and migrate into fracture zone Calluses stabilize the break: external callus of cartilage and bone surrounds break internal callus develops in marrow cavity

128 Fracture Repair: Step 3 Figure 6–15 (Step 3)

129 Fracture Repair: Step 3 Osteoblasts:
replace central cartilage of external callus with spongy bone

130 Fracture Repair: Step 4 Figure 6–15 (Step 4)

131 Fracture Repair: Step 4 Osteoblasts and osteocytes remodel the fracture for up to a year: reducing bone calluses PLAY Steps in the Repair of a Fracture

132 The Major Types of Fractures
Pott’s fracture Figure 6–16 (1 of 9)

133 The Major Types of Fractures
Comminuted fractures Figure 6–16 (2 of 9)

134 The Major Types of Fractures
Transverse fractures Figure 6–16 (3 of 9)

135 The Major Types of Fractures
Spiral fractures Figure 6–16 (4 of 9)

136 The Major Types of Fractures
Displaced fractures Figure 6–16 (5 of 9)

137 The Major Types of Fractures
Colles’ fracture Figure 6–16 (6 of 9)

138 The Major Types of Fractures
Greenstick fracture Figure 6–16 (7 of 9)

139 The Major Types of Fractures
Epiphyseal fractures Figure 6–16 (8 of 9)

140 The Major Types of Fractures
Compression fractures Figure 6–16 (9 of 9)

141 What are the effects of aging on the skeletal system?

142 Age and Bones Bones become thinner and weaker with age
Osteopenia begins between ages 30 and 40 Women lose 8% of bone mass per decade, men 3%

143 Effects of Bone Loss The epiphyses, vertebrae, and jaws are most affected: resulting in fragile limbs reduction in height tooth loss

144 Osteoporosis Severe bone loss Affects normal function
Over age 45, occurs in: 29% of women 18% of men

145 Hormones and Bone Loss Estrogens and androgens help maintain bone mass
Bone loss in women accelerates after menopause

146 Cancer and Bone Loss Cancerous tissues release osteoclast-activating factor: that stimulates osteoclasts and produces severe osteoporosis

147 SUMMARY (1 of 5) Bone shapes, markings, and structure
The matrix of osseous tissue Types of bone cells

148 SUMMARY (2 of 5) The structures of compact bone
The structures of spongy bone The periosteum and endosteum

149 SUMMARY (3 of 5) Ossification and calcification
Intramembranous ossification Endochondrial ossification

150 SUMMARY (4 of 5) Blood and nerve supplies
Bone minerals, recycling, and remodeling The effects of exercise

151 SUMMARY (5 of 5) Hormones and nutrition Calcium storage
Fracture repair The effects of aging

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