Bone formation (ossification/osteogenesis) and growth

Question 1

How does the medullary cavity enlarge during growth in thickness?

Answer 1

Osteoclasts destroy the bone tissue lining the medullary cavity enabling it to enlarge as the bone increases in thickness.

Question 2

Where does the growth in length of a bone occur?

Answer 2

At the epiphyseal growth plate

Question 3

What zone (within the epiphyseal plate) is nearest the epiphysis, consists of small scattered chondrocytes and does NOT function in bone growth (anchors the epiphyseal plate to the epiphysis of the bone)?

Answer 3

Zone of resting cartilage

Question 4

What zone consists of slightly larger chondrocytes arranged like stacks of coins and undergoes institual growth as they divide and secrete ECM?

Answer 4

Zone of proliferating cartilage

Question 5

What zone has large, maturing chondrocytes arranged in columns?

Answer 5

Zone of hypertrophic cartilage

Question 6

What zone is only a few cells thick and is mostly dead chondrocytes (ECM around them has calcified)?

Answer 6

Zone of calcified cartilage (nearest to diaphysis)

Question 7

What occurs on the epiphyseal side of the epiphyseal plate during growth in length?

Answer 7

Interstitial growth of cartilage via mitosis: chondrocytes proliferate

Question 8

What occurs on the diaphyseal side of the epiphyseal plate during growth in length?

Answer 8

Replacement of cartilage of the plate by bone: osteoblasts dissolve calcified cartilage and osteoblasts build bone

Question 9

Which part of the long bone increases in length?

Answer 9

Diaphysis

Question 10

Which part of the bone enlarges as bone increases in thickness?

Answer 10

Medullary cavity

Question 11

Does healing occur faster in bone or cartilage? Why?

Answer 11

Healing is faster in bone than in cartilage because there are no blood vessels in cartilage.