7.1.2 Cells Associated With Bone

There are three types of cells associated with bone (derived from osteogenic cells): osteoblasts, osteocytes, and osteoclasts. Each type has a specific role in bone formation, maintenance, and resorption.

Definition

• Osteoblasts — bone forming cells
• Osteocytes — maintain healthy bone tissue
• Osteoclasts — bone destroying cells

Main Idea

• There are three types of cells associated with bone.
• They are derived from osteogenic cells.
• Osteoblasts are bone forming cells.
• They synthesize and secrete unmineralized ground substance.
• Once osteoblasts are surrounded by matrix, they become osteocytes.
• Osteocytes maintain healthy bone tissue.
• They secrete enzymes and influence bone mineral content.
• They regulate calcium release from bone tissue to blood.
• Osteoclasts are bone destroying cells.
• They perform bone resorption.
• They break down bone and deposit calcium and phosphate in the blood.
• The work of osteoclasts is important to the growth and repair of bone.

Core Concept

• Osteogenic cell = develops into osteoblast
• Osteoblast = forms bone matrix
• Osteocyte = maintains bone tissue
• Osteoclast = functions in resorption; breakdown of bone matrix
• Osteoblasts = synthesize and secrete unmineralized ground substance
• Osteocytes = maintain healthy bone tissue; regulate calcium release
• Osteoclasts = break down bone; deposit calcium and phosphate in blood

Detailed Explanation

Cells Associated with Bone

There are three types of cells associated with bone (derived from osteogenic cells).

1. Osteoblasts

• Osteoblasts are bone forming cells.
• They synthesize and secrete unmineralized ground substance.
• Once the osteoblasts are surrounded by matrix, they become the osteocytes.

2. Osteocytes

• Osteocytes maintain healthy bone tissue by secreting enzymes and influencing bone mineral content.
• They also regulate the calcium release from bone tissue to blood.

3. Osteoclasts

• Osteoclasts are bone destroying cells.
• They perform bone resorption, i.e., they breakdown bone and deposit calcium and phosphate in the blood.
• The work of osteoclasts is important to the growth and repair of bone.

Summary Table of Bone Cells

Detailed Functions

Intermediate Level

Bone Cells

Detailed Functions

Origin of Bone Cells

Formula / Mathematical Form

Not applicable to this topic.

Solved Example

Not applicable to this topic (descriptive topic).

Important Points

• 1. Three types of cells are associated with bone.
• 2. They are derived from osteogenic cells.
• 3. Osteoblasts are bone forming cells.
• 4. Osteoblasts synthesize and secrete unmineralized ground substance.
• 5. Osteoblasts become osteocytes when surrounded by matrix.
• 6. Osteocytes maintain healthy bone tissue.
• 7. Osteocytes secrete enzymes.
• 8. Osteocytes influence bone mineral content.
• 9. Osteocytes regulate calcium release from bone to blood.
• 10. Osteoclasts are bone destroying cells.
• 11. Osteoclasts perform bone resorption.
• 12. Osteoclasts break down bone.
• 13. Osteoclasts deposit calcium and phosphate in the blood.
• 14. Osteoclasts are important for growth and repair of bone.
• 15. Balance between osteoblasts and osteoclasts is essential.

Remember

• - Osteogenic cell = develops into osteoblast
• - Osteoblast = forms bone matrix
• - Osteocyte = maintains bone tissue
• - Osteoclast = functions in resorption; breakdown of bone matrix
• - Osteoblasts = synthesize and secrete unmineralized ground substance
• - Osteocytes = maintain healthy bone tissue; regulate calcium release
• - Osteoclasts = break down bone; deposit calcium and phosphate in blood

Common Mistakes

• 1. Confusing osteoblasts and osteoclasts — Osteoblasts = build bone; osteoclasts = break down bone.
• 2. Mixing up osteocytes and osteoblasts — Osteocytes = maintain; osteoblasts = build.
• 3. Forgetting the role of osteoclasts — They break down bone and release calcium.
• 4. Thinking osteoblasts become osteoclasts — Osteoblasts become osteocytes.
• 5. Forgetting the role of osteocytes — They maintain bone tissue and regulate calcium.
• 6. Mixing up the functions — Build, maintain, break down.
• 7. Believing bone is not living — Bone is living tissue with cells.
• 8. Thinking bone remodeling is only for growth — Bone remodeling is also for repair.
• 9. Mixing up the origin of bone cells — Osteoblasts from osteogenic cells; osteoclasts from hematopoietic stem cells.
• 10. Forgetting the balance — Balance between osteoblasts and osteoclasts is essential.

Quick Revision

There are three types of cells associated with bone (derived from osteogenic cells) i.e., osteoblasts are bone forming cells that synthesize and secrete unmineralized ground substance. Once the osteoblasts are surrounded by matrix, they become the osteocytes. Osteocytes maintain healthy bone tissue by secreting enzymes and influencing bone mineral content. They also regulate the calcium release from bone tissue to blood. Osteoclasts are bone destroying cells. They perform bone resorption, i.e., they breakdown bone and deposit calcium and phosphate in the blood. The work of osteoclasts is important to the growth and repair of bone.

60-Second Revision

• Osteogenic cell = develops into osteoblast
• Osteoblast = forms bone matrix
• Osteocyte = maintains bone tissue
• Osteoclast = functions in resorption; breakdown of bone matrix
• Osteoblasts = synthesize and secrete unmineralized ground substance
• Osteocytes = maintain healthy bone tissue; regulate calcium release
• Osteoclasts = break down bone; deposit calcium and phosphate in blood
• Warning: Osteoblasts build bone; osteoclasts break down bone

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