Transcript i Fundamentals of Anatomy & Physiology SIXTH EDITION Chapter 6, part 1 Osseous Tissue and Skeletal Structure Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings.

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Fundamentals of
Anatomy & Physiology
SIXTH EDITION
Chapter 6, part 1
Osseous Tissue and Skeletal
Structure
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Learning Objectives
• Describe the functions of the skeletal system.
• Classify bones and identify the major markings.
• Identify cell types in bone and list their functions.
• Compare spongy and compact bone.
• Compare intramembranous and endochondral
ossification.
• Discuss the effects of nutrition, hormones,
exercise and aging on the bones.
• Describe the types of fractures.
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The Skeletal System: An Introduction
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The skeletal system includes
• Bones of the skeleton
• Cartilages, ligaments and other connective
tissues that stabilize and connect
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Functions of the skeletal system
• Support
• Storage of minerals and lipids
• Blood cell production
• Protection
• Leverage
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SECTION 6-2
A Classification of Bones
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Bone shapes
• Long
• Flat
• Short
• Irregular
• Sesamoid
• Sutural
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Figure 6.1 Classification of Bones by Shape
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Figure 6.1
Bone structure = two types of bone
• Compact bone (dense)
• Spongy bone (cancellous)
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A typical long bone includes
• Diaphysis
• Epiphyses
• Metaphysis
• Articular cartilage
• Marrow cavity
• Filled with red or yellow marrow
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Figure 6.2 Bone Structure
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Figure 6.2
SECTION 6-3
Bone Histology
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Osseous tissue
• Supporting tissue with a solid matrix
• Crystals of hydroxyapatite
• Minerals deposited in lamellae
• Covered by periosteum
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Cells in bone:
• Osteocytes = mature bone cells
• In lacunae
• Connected by canaliculi
• Osteoblasts synthesize new matrix
• Osteogenesis
• Osteoclasts dissolve bone matrix
• Osteolysis
• Osteoprogenitor cells differentiate into
osteoblasts
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Figure 6.3 The Histology of Compact Bone
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Figure 6.3a
Figure 6.3 The Histology of Compact Bone
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Figure 6.3b, c
Compact bone and spongy bone
• Basic unit of compact bone is an osteon
• Osteocytes arranged around a central canal
• Perforating canals extend between adjacent
osteons
• Spongy bone contains trabeculae
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Figure 6.4 The Structure of Osseus Tissue
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Figure 6.4
Bones and stress
• Compact bone located where stresses are limited
in direction
• Spongy bone located where stresses are weaker or
multi-directional
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Figure 6.5 The Distribution of Forces on a Long
Bone
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Figure 6.5
Bones are:
• Covered by periosteum
• Lined by endosteum
PLAY
Animation: Axial Dissections
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Bone development and growth
• Ossification = converting other tissue to bone
• Calcification = depositing calcium salts within
tissues
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Intramembranous ossification
• Begins with osteoblast differentiation
• Dermal bones produced
• Begins at ossification center
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Figure 6.7 Intramembranous Ossification
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Figure 6.7
Endochondral ossification
• Cartilage model gradually replaced by bone at
metaphysis
• Increasing bone length
• Timing of epiphyseal closure differs
• Appositional growth increases bone diameter
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Figure 6.8 Endochondral Ossification
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Figure 6.8a
Figure 6.8 Endochondral Ossification
PLAY
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Animation: Endochondral Ossification
Figure 6.8b
Figure 6.9 Bone Growth at an Epiphyseal
Cartilage
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Figure 6.9
Figure 6.10 Appositional Bone Growth
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Figure 6.10a
Figure 6.10 Appositional Bone Growth
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Figure 6.10b
Figure 6.11 The Circulatory Supply to a Mature
Bone
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Figure 6.11
SECTION 6-5
The Dynamic Nature of Bone
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continually changing
• Remodeling
• Exercise
• Hormone levels
• Growth hormone and thyroxine increase bone
mass
• Calcitonin and PTH control blood calcium
levels
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Figure 6.12 A Chemical Analysis of Bone
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Figure 6.12
The skeleton is a calcium reserve
• 99% body’s calcium in the skeleton
• Calcium ion concentration maintained by bones
GI tract and kidneys
• Calcitonin and PTH regulate blood calcium levels
• Calcitonin decreases blood calcium levels
• PTH increases blood calcium levels
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Figure 6.13 Factors that Alter the Concentration
of Calcium Ions in Body Fluids
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Figure 6.13a
Figure 6.13 Factors that Alter the Concentration
of Calcium Ions in Body Fluids
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Figure 6.13b
Fracture repair
• Fracture hematoma
• External callus
• Internal callus
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Figure 6.14 Steps in the Repair of a Fracture
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Figure 6.14
SECTION 6-6
Bone Markings (Surface Features)
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Bone markings
• Are characteristic for each bone and each
individual
• Markings include
• Elevations
• Projections
• Depressions
• Grooves and tunnels
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SECTION 6-7
Aging and the Skeletal System
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Effects of aging include
• Osteopenia
• Osteoporosis
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Figure 6.16 The Effects of Osteoporosis
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Figure 6.16
You should now be familiar with:
• The functions of the skeletal system.
• Bones and their major markings.
• Cell types in bone and their functions.
• Spongy and compact bone.
• Intramembranous and endochondral ossification.
• The effects of nutrition, hormones, exercise and
aging on the bones.
• The types of fractures.
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