bone growth-formation and remodeling

Question 1

what is Bone formation
(Ossification)

Answer 1

– process of new
bone production

Question 2

Compact bone

Answer 2

– starts as cartilage
- osteoblasts (bone forming
cells) in cartilage
- discharge osteoids (collagen,
a fibrous protein, and mucopolysaccharide)
- inorganic salts get deposited
- hardens to form bone

Question 3

Cancellous Bone

Answer 3

– starts as fibrous membranes
- Osteoblasts discharge osteoid into membrane
- Forms sponge-like bundles of fibres

Question 4

how does Bone Remodelling work

Answer 4

• Bone growth doesn’t occur by cell division
• Two phases:
  1. Osteoclasts
  (bone reabsorbing cells) remove old bone by releasing acids and
  enzymes.
  2. Osteoblasts deposit new tissue.
• Bone remodelling is highest during early years and declines
  until age 35
• Then reabsorption starts to exceed bone reformation (5-10%
  loss in bone mass per decade after 40)

Question 5

Epiphyseal plates vs. Epiphyseal lines

Answer 5

Plates: known as growth plates, located
at epiphysis of long bones, cartilage

Lines: fusion of plates, no more growth