Topic 28 - Supportive tissue: Bone

Question 1

Bone: what is it?

Answer 1

-Connective tissue, cells and fibres embedded in non-bending ground substance.

Question 2

Bone:
Function:

Answer 2

• Provides internal support, muscle and tendon attachment, protects brain and organs, contains bone marrow, and serves as calcium source.
• Tissue is renewed and remodeled throughout life.

Question 3

Difference from cartilage?

Answer 3

• Canalicular system exists with the bones.
• Direct vascular supply.
• Appositional growth only

Question 4

Structure (Long bone):

Answer 4

• Proximal epiphysis
• Diaphysis
• Distal epiphysis
• Compact bone
• Periosteum
• Endosteum

Question 5

Proximal epiphysis

Answer 5

proximal region, composed of cancellous (spongy) bone

Question 6

Diaphysis

Answer 6

bone shaft

Question 7

Distal epiphysis

Answer 7

distal region of the bone

Question 8

Compactbone

Answer 8

surrounds the medullary cavity (yellow bone marrow and vessels)

Question 9

Periosteum

Answer 9

tissue covering entire bone, two layers:

• Inner vascular and cellular osteogenic layer.
• Sharpey fibres: collagen fibres continuous with the collagen fiber system of lamellae. Fix periosteum to bone

Question 10

Endosteum

Answer 10

layer of squamous cells lining bone inside the ion barrier. Role in mineral homeostasis.

Question 11

Tissue components:

Cells:

Answer 11

• Osteoblasts: osteocyte progenitors.
• Osteocytes: contained within osteons.
• Osteons: concentric. Contain osteocytes and concentric lamellae. Form around Haversian canals. Space between osteons is filled by interstitial lamellae (remnants of old osteons).
• Osteoclasts

Question 12

Bone matrix: Osteoid

ECM?

Answer 12

-ECM: organic compounds provide flexibility (collagen fibres and GAGs) and inorganic compunds (hydroxyapatite crystals) provide firmness.