Book contents
- Frontmatter
- Contents
- List of contributors
- Preface
- Part 1 Molecular and cellular environment of bone
- 1 Endochondral bone formation and development in the axial and appendicular skeleton
- 2 The role of osteoblasts
- 3 Osteoclasts: characteristics and regulation of formation and activity
- 4 Bone matrix proteins
- 5 Local regulators of bone turnover
- 6 The PTH/PTHrP system and calcium homeostasis
- 7 Vitamin D metabolism
- 8 Sodium-dependent phosphate transport in kidney, bone and intestine
- 9 Molecular genetic analysis of growth factor signaling in bone
- Part II Determinants of peak bone mass
- Part III Pathophysiology of the aging skeleton
- Part IV Clinical aspects of osteoporosis
- Index
3 - Osteoclasts: characteristics and regulation of formation and activity
Published online by Cambridge University Press: 01 June 2011
- Frontmatter
- Contents
- List of contributors
- Preface
- Part 1 Molecular and cellular environment of bone
- 1 Endochondral bone formation and development in the axial and appendicular skeleton
- 2 The role of osteoblasts
- 3 Osteoclasts: characteristics and regulation of formation and activity
- 4 Bone matrix proteins
- 5 Local regulators of bone turnover
- 6 The PTH/PTHrP system and calcium homeostasis
- 7 Vitamin D metabolism
- 8 Sodium-dependent phosphate transport in kidney, bone and intestine
- 9 Molecular genetic analysis of growth factor signaling in bone
- Part II Determinants of peak bone mass
- Part III Pathophysiology of the aging skeleton
- Part IV Clinical aspects of osteoporosis
- Index
Summary
Introduction
Bone tissue adapts itself continuously to changing demands during development and growth (modeling) and in response to stress or damage (remodeling). The modeling and remodeling processes involve degradation of bone tissue by large multinucleated cells, called osteoclasts, and synthesis and deposition of new bone by mononuclear cuboidal cells lining bone, called osteoblasts. A close anatomical and functional relationship exists between resorptive and formative cells at discrete remodeling sites called ‘basic multicellular units of bone remodeling’ or BMU (Frost, 1966). This is, in all likelihood, responsible for the phenomenon in which treatments of metabolic bone disease developed to inhibit resorption often result in simultaneous inhibition of formation. The mechanism(s) whereby the actions of the resorbing osteoclasts and the bone forming osteoblasts are co-ordinated are not yet clear. Nevertheless, striking progress has been made in our understanding of osteoblast—osteoclast interaction with regard to regulating osteoclast formation.
This chapter focuses on osteoclasts and osteoclastic bone resorption. Morphological characteristics of osteoclasts, the processes whereby osteoclasts degrade bone, the origin of osteoclasts and the regulation of osteoclast formation and activity will be reviewed here.
Morphological characteristics of osteoclasts
Osteoclasts are easily recognized in histological sections of bone tissue as large multinucleated cells with up to 25 nuclei and are found in close association with bone surfaces (Fig. 3.1).
- Type
- Chapter
- Information
- The Osteoporosis Primer , pp. 36 - 45Publisher: Cambridge University PressPrint publication year: 2000