chapter 6 part 5

Question 1

Zone of resting cartilage:

Answer 1

Slowly dividing chondrocytes.

Question 2

Zone of proliferation:

Answer 2

New cartilage is produced on the epiphyseal side of the plate as the chondrocytes divide and form stacks of cells.

Question 3

Zone of hypertrophy:

Answer 3

Chondrocytes mature and enlarge.

Question 4

Zone of calcification:

Answer 4

Matrix is calcified, and chondrocytes die.

Question 5

Ossified bone:

Answer 5

The cartilage on the diaphyseal side of the plate is replaced by bone.

Question 6

growth of articular cartilage

Answer 6

• Epiphyses increase in size due to growth at the articular
  cartilage.
• Increases size of bones with no epiphyses:
• For example, short bones.
• Chondrocytes near the surface of the articular cartilage similar to those in zone of resting cartilage.
• When the epiphyses reach their full size, the growth of cartilage and its replacement by bone cease.
• Articular cartilage persists throughout life and does not become ossified.

Question 7

bone growth in width

Answer 7

• Bone width is one of the most critical factors of bone strength.
• Osteoblasts from the periosteum lay down bone under the periosteum which gradually increases the amount the bone surrounding the medullary cavity.
• Osteoclasts form the endosteum reabsorb bone surrounding the medullary cavity, which enlarges over time.

Question 8

factors affecting bone growth

Answer 8

• Nutrition, lack of calcium, protein and other nutrients during growth and development can cause bones to be small.
• Vitamin D.
• Necessary for absorption of calcium from intestines.
• Can be ingested or manufactured in the body.
• Rickets: lack of vitamin D during childhood.
• Osteomalacia: lack of vitamin D during adulthood leading to softening of bones.
• Vitamin C.
• Necessary for collagen synthesis by osteoblasts.
• Scurvy: deficiency of vitamin C.
• Lack of vitamin C also causes wounds not to heal, teeth to fall out

Question 9

factors affecting bone growth part 2

Answer 9

Hormones.
* Growth hormone from anterior pituitary.
* Stimulates interstitial cartilage growth and appositional bone growth.
* Thyroid hormone required for growth of all tissues.
* Reproductive hormones such as estrogen and testosterone.
* Cause growth at puberty, but also cause closure of the epiphyseal plates and the cessation of growth

Question 10

Gigantism

Answer 10

excessive growth hormone
secretion during growing years

Question 11

fracture patterns in a bone

Answer 11

Linear, spiral, avulsion, stress, compression.

Question 12

Number of fragments in the fractured bone

Answer 12

Incomplete, complete, communited

Question 13

Callus ossification

Answer 13

Callus replaced by woven, spongy bone.

Question 14

Bone remodeling

Answer 14

Replacement of spongy bone and damaged
material by compact bone. Sculpting of site by osteoclasts