Bone growth and remodeling

Question 1

name and describe the events in the four zones of the epiphyseal plate

Answer 1

1. zone of rest: cartilage attaches to the epiphysis.
2. zone of proliferation: new cartilage is produced on the epiphyseal side of the plate as the chondrocytes divide and form stacks of cells.
3. zone of hypertrophy: chondrocytes mature and enlarge.
4. zone of calcification: matrix is calcified and the chondrocytes die.

Question 2

explain how the epiphyseal plate remains the same thickness while the bone increases in length

Answer 2

because the rate of cartilage growth on the epiphyseal side of the plate is equal to the rate of cartilage replacement by bone on the diaphyseal side of the plate.

Question 3

explain the process of growth at the articular cartilage

Answer 3

increases the size of bones that do not have an epiphysis, such as short bones; chondrocytes near surface of articular cartilage are similar to those in zone of resting cartilage

Question 4

what happens to the epiphyseal plate and the articular cartilage when bone growth ceases?

Answer 4

the epiphyseal plate ceases, while the articular cartilage persists throughout life and does not ossify like the epiphyseal plate does

Question 5

describe how new osteons are produced as a bone increases in width

Answer 5

When a bone grows in width slowly, the surface of the bone becomes smooth as osteoblasts from the periosteum lay down even layers of bone to form circumferential lamellae. The circumferential lamellae break down during remodeling to form osteons.

Question 6

explain how illness or malnutrition can affect bone growth

Answer 6

It affects the rate of cell proliferation or the production of collagen and other matrix components.

Question 7

how do vitamins D and C affect bone growth?

Answer 7

Without vitamin D children can get a disease called rickets, this is resulting from reduced mineralization of the bone matrix. Vitamin C deficiency results in bones and cartilage that are deficient in collagen because collagen synthesis is impaired.

Question 8

why is it important for bone remodeling to occur?

Answer 8

Bone remodeling converts woven bone into lamellar bone and functions in bone growth, changes in bone shape, adjustment of the bone to stress, bone repair, and calcium ion regulation of body

Question 9

rickets

Answer 9

lack of vitamin D during childhood

Question 10

osteomalacia

Answer 10

lack of vitamin D during adulthood leading to softening of bones

Question 11

scurvy

Answer 11

deficiency of vitamin C

Question 12

bone repair

Answer 12

process of repairing damage done to the bone

Question 13

basic multicellular units

Answer 13

groups of osteoclasts and osteoblasts that remodel bones

Question 14

what are the 2 types of commone stresses on bones?

Answer 14

mechanical stress and physical stress

Question 15

what happens if you were to remove any stress to the bones?

Answer 15

reduced stress results in more osteoclast activity as compared to osteoblast activity

Question 16

increased stress causes bone to increase in strength and this occurs by …

Answer 16

remodeling, formation of additional bone, and alter trabeculae to align with stress

Question 17

wolff’s law

Answer 17

states that bone remodeling, responds to stresses in the bone leading to such things as differences in bone size between left and right hands, thicker bone where muscles attach

exercising stimulates bone remodeling and ultimately bone strength so when you work out, you’re building bone as well as muscle