C6 12-16

Question 1

Which hormones regulate bone growth? 5

Answer 1

GH, TH, sex hormones (estrogen/testosterone) cortisol, seratonin

Question 2

Which hormones regulate bone remodeling? 3

Answer 2

Calcitonin, PTH, calcitriol (main hormones are PTH and Cacitonin)

Question 3

GH-growth hormone (somatropin)

Answer 3

protein synthesis and cell growth throughout body

Question 4

Thyroid hormone

Answer 4

Cell metabolism and increase osteoblast activity

Question 5

Sex hormones

Answer 5

Increase rate of bone formation at puberty

Question 6

Cortisol

Answer 6

Catabolic and anti-growth effects (counteracts GH/TH effect on bone growth)

Question 7

Calcitriol

Answer 7

Active form of vit d. (calcium homeostasis)

Question 8

Parathyroid hormone PTH

Answer 8

Secreted by parathyroid glands in response to reduced blood calcium
Targets: osteoclasts to resorb bone matrix
Kidneys to retain calcium
Small intestine to increase absorption of calcium

Question 9

Calcitonin

Answer 9

Released from thyroid in response to high blood levels of calcium
Lowers calcium levels

Question 10

How does physical stess regulate bone remodeling?

Answer 10

Bone remodels/grows in response to demands placed on it. Stress is detected by osteocytes and communicated to osteoblasts which then increase synthesis of osteoid and this is followed by the deposition of mineral salts. (mechanical stress results from muscle contraction and gravitational pull)

Question 11

Steps of fracture repair?

Answer 11

HEMATOMA - clotted blood at fracture, Fibrocartilaginous (SOFT) CALLUS forms - chondroblasts form dense reg ct associated with cartilage, BONY CALLUS - osteoprogenitor cells become osteblasts and produce the trabeculae of primary (spongy) bone, BONE IS REMODELED - compact bone replaces spongy bone

Question 12

Types of fractures?

Answer 12

Stress, simple, compound

Question 13

Osteopenia

Answer 13

Inadequate ossification
Decrease in bone mass
Epiphysis, vertebrae, jaw affected most

Question 14

Osteomalacia

Answer 14

Bones are poorly mineralized - osteoid is produced, but calcium salts are not adequately deposited so bones are soft and weak

Question 15

Osteoporosis

Answer 15

Bone resorption exceeds bone deposition. Bones become very fragile. Risk factors: petite body, insufficient exercise, not enough calcium/protein in diet, smoking, abnormal vit d receptors, hormone condition. Treatment: Calcium/vit d supplements, exercise, HRT, Bisphophates

Question 16

Paget’s disease

Answer 16

Increase in number of osteoclasts and resorption of bone + the deposition of new bone resulting in disorderly bone remodeling.

Question 17

Osteosarcoma

Answer 17

Most common form of bone cancer occuring in tibia/femur/humerous of males 10-25

Question 18

Wolff’s law

Answer 18

Bone grows or remodels in response to demands placed upon it