Bone Ossification

Question 1

stimulates osteoclasts to degrade bone matrix and release Ca into blood

Answer 1

parathyroid hormone

Question 2

in bone growth, ___ “run” & ___ “chase”

Answer 2

chondrocytes

osteoclasts

Question 2

Identify A-F.

Answer 2

A. epiphysis

B. resting cartilage

C. proliferation

D. hypertrophy

E. calcification

F. ossification

Question 3

forms mid-shaft (diaphysis). impedes diffusion to cells in center- acts as signal to calcify fetal hyaline cartilage

Answer 3

periosteal bone collar

Question 3

Identify zones 1-5.

Answer 3

1. Resting cartilage
2. Proliferating cartilage
3. Hypertrophic cartilage
4. Calcified cartilage
5. Ossification

Question 4

Identify 1-3.

Answer 4

1. hyaline cartilage
2. bone collar
3. periosteum

Question 4

2 controls impacting bone remodeling?

Answer 4

Calcitonin/Parathyroid hormone

bone response to mechanical stress/gravity

Question 5

stimulates calcium salt deposit in bone. inhibits osteoclasts.

Answer 5

calcitonin

Question 6

calcified cartilage contains ___ collagen.

Bone contains __ collagen.

Answer 6

type 2

type 1

Question 8

type of ossification?

Answer 8

intramembranous ossification

Question 10

steps of endochondral ossification?

Answer 10

1. fetal hyaline cartilage develops
2. cartilage calcifies, periosteal bone collar forms
3. primary ossification centers in diaphysis
4. secondary ossification centers in epiphysis
5. bone replaces cartilage
6. epiphyseal plates ossify- form epiphyseal lines

Question 11

Identify 1-5.

Answer 11

1. mesenchyme
2. osteoblast
3. blood vessels
4. osteoid
5. osteocyte

Question 12

in endochondral ossification, bone replaces cartilage everywhere except…

Answer 12

articular cartilage & epiphyseal plates

Question 13

Identify zones 1-5.

Answer 13

(reverse)

1. cartilage ossification
2. cartilage calcification
3. hypertrophic cartilage
4. proliferation of cartilage
5. resting cartilage

Question 15

osteogenesis where bone cells differentiate directly from mesenchymal cells to produce osteoid- no precursor, nothing placed down ahead of this.

Answer 15

intramembranous ossification

Question 16

calcitonin is released by the ___.

parathyroid hormone is released by the ___.

Answer 16

thyroid gland- parafollicular cells

parathyroid glands

Question 17

as bone increases in diameter, what happens at periosteal layer? what happens at endosteal surface?

Answer 17

periosteal layer- osteoblasts secrete bone matrix (appositional growth- bones grow wider)

endosteum- osteoclasts break down matrix (to avoid bones becoming too heavy)

Question 18

osteogenesis where mesenchyme is 1st replaced by hyaline cartilage, then bone model replaces the cartilage

Answer 18

endochondral ossification

Question 19

steps of intramembranous ossification

Answer 19

1) ossification centers form from thickened regions of mesenchyme 2) osteoid undergoes calcification 3) woven bone forms 4) lamellar bone replaces woven bone (compact/spongy bone form)