Bone Development

Question 1

Intramembranous Ossification steps:

Answer 1

1. Ossification centers form within thickened mesenchyme
2. Osteoid undergoes calcification
3. Woven bone and periosteum form
4. Lamellar bone replaces woven bone as compact and spongy bone form

Question 2

Endochondral Ossification Steps:

Answer 2

1. Fetal hyaline cartilage develops
2. Cartilage calcified, bone collar forms around diaphysis
3. Primary ossification center forms in diaphysis
4. Secondary ossification centers form in epiphyses
5. Bone replaces cartilage (except articular cart and epiphyseal plate)
6. Epiphyseal plates ossify into epiphyseal line (after puberty)

Question 3

Bone increases in diameter/width with _____ growth:

• At _____ surface of bone -> osteoblasts secrete bone matrix
• At _____ surface of bone -> osteoclasts breakdown bone matrix

Answer 3

Appositional

Periosteal

Endosteal

Question 4

Two controls impacting bone remodeling:

Answer 4

1. Negative feedback loop for calcium homeostasis (calcitonin, parathyroid hormone) (impacts WHEN remodeling occurs)
2. Bone’s response to mechanical stress and gravity (impacts WHERE remodeling occurs)

Question 5

Ossification Type?

1. Mesenchyme -> Bone
2. Mesenchyme -> Hyaline -> Hyaline Cartilage -> Bone

Answer 5

1. Intramembranous Ossification

2. Endochondral Ossification