Bone Structure and Classification

Question 1

What does bone consist of?

Answer 1

Specialised form if connective tissue consisting of cells and matrix. Matrix is mineralised with calcium phosphate which gives hard texture and reservoir for calcium.

Question 2

Different classes of bone:

Answer 2

Compact: dense bone that forms outer layer of bone
Spongy: cancellous bone that contains meshwork of thin trabeculae or spicules of bone tissue. Found in epiphyses and metaphyses of long bones

Question 3

Long bone features:

Answer 3

• Diaphysis: shaft of long bone
• Epiphysis: expanded area of either side of the bone covered by articular cartilage
• Metaphysis; lies between the diaphysis and epiphysis.; conical region adjacent to where active bone growth occurs
• Marrow cavity: central portion of the shaft.
• Articular cartilage (hyaline cartilage)
• Periosteum: a thin fibrous connective tissue sheath or capsule that surrounds the shaft of a bone but does not extend to the articular surfaces which are covered by articular cartilage.
• Compact bone

Question 4

3 major cell types in bone cell formation

Answer 4

• Osteoblasts: cells that form new bone by laying down osteoid
• Osteocytes: mature bone cells, formerly osteoblasts that have become surrounded by bone matrix and responsible for maintaining bone matrix
• Osteoclasts: large cells that enzymatically dissolve matrix and commonly found at sites of active bone remodelling

Question 5

Features of compact bone

Answer 5

• Osteon
• Vein
• Artery
• Lamellae of bone matrix with osteocytes embedded in the lamellae
• osteocytes

Question 6

The Osteon

Answer 6

• Found in compact bone due to haversian systems
• cylindrical unit of bone consisting of a central canal, which contains the neurovascular bundle supplying the osteon.
• this canal surrounded by lamellae of bone matrix and radially orientated small canaliculi that contain the processes of osteocytes.

Question 7

Disease profile: Rickets

Answer 7

calcium defiency during active growth leads to matric formation that is not normally mineralised with calcium
- Occurs from a lack or dietary calcium or Vit D deficiency as Vit D absorbs calcium in small intestine or both