Question

Need to know answers for both a and b

A. compare and contrast endochondral ossification with intramembranous ossification?

B. what roles do osteoblasts, osteoclasts and osteocytes play in endochondral bone formation and in bone remodeling and bone fracture? (describe bone remodeling and bone fractures)

Answer 1

1. ANSWER: ENCHONDRAL OSSIFICATION- It is a type of ossification taking place from the centre of cartilages and involving the deposition of lime salts in the matrix of the cartilage followed by secondary absorption and replacement of true bony tissue.

A cartilage is formed first and then the bone is laid on it.

Proceeds through thw formation of intermediate cartilage.

Important in the formation of long bones.

It usually takes longer time to form a bone.

Development stops at 2 yrs.

INTRAMEMBRANOUS OSSIFICATION- Development of osseous tissue within the mesenchymal tissue without any prior cartilage formation.

Bone is directly formed from a mesenchyme.

No intermediate cartilage is formed.

Important in the formation of flat bones.

It takes less time to form bones.

Stops at an age of 18 to 21 yrs.

2. ANSWER: Osteoblasts not only play a key role in bone formation but also synthesizes multiple bone matrix proteins, bit also regulate the maturation of osteoclast by soluble factors and cognate interaction, resulting in the bone resorption. Osteocytes which are abundant cells in the bone tissue, detect the mechanical loading and regulate the bone formation by osteoblast and bone resorption by osteoclast.