Which of these lists the six categories for classifying bone by shape?

1. Which of these lists the six categories for classifying bone by shape? • Intramembranous; periosteal; diaphysis mesenchymal; endochondral; interstitial • Flat; irregular; short; long; sesamoid; sutural • Long; short; mesenchymal; intramembranous; endochondral; epiphyseal • Femur; sternum; wormian; pelvis; patella; vertebra

2. Which bony marking is correctly paired with its description? • Fissure; depression • Facet; opening • Tuberosity; process formed where tendons or ligaments attach • Spine; process formed for articulation with adjacent bones

3. Which of these bony markings would become more pronounced with weight-bearing exercise? • Tuberosities • Condyles • Processes • Heads

4. Which of the following describes osteoprogenitor cells? • Divide to produce daughter cells that differentiate into osteoblasts • Assist in elevating local concentrations of calcium phosphate • Multinucleate and derive from same stem cells that produce monocytes • Maintain protein and mineral content of surrounding matrix

5. How would the strength of a bone be affected if the ratio of collagen to hydroxyapatite increased? Strength increases, flexibility increases. Strength increases, flexibility decreases. Strength decreases, flexibility decreases. Strength decreases, flexibility increases.

6. If the activity of osteoclasts exceeds the activity of osteoblasts in a bone, how will the mass of the bone be affected? Stable mass, but re-positioned matrix Mass will not be affected More mass Less mass

7. What are functional relationships between compact and spongy bone? • Spongy bone resists stress from many directions/compact bone is extremely strong when stressed along the axis of alignment • Spongy bone is strong along its main axis/compact bone resists stress from many directions • Both spongy and compact bone resist stresses from all angles except a sudden force to the side of the bone • None of these is correct

8. A sample of bone has lamellae, which are not arranged in osteons. Is this sample from the epiphysis or diaphysis? It is from the diaphysis. It is from the medullary cavity of a long bone. It could be from either epiphysis or diaphysis. It is from the epiphysis.

9. Which of the following is/are correct concerning the periosteum? It has a fibrous outer layer and cellular inner layer. It provides a route for nerves and blood vessels into bone. It actively participates in bone growth and repair. All of the above are correct

10. During intramembranous ossification, which type(s) of tissue is/are replaced by bone? Hyaline cartilage Fibrous connective tissue Mesenchymal connective tissue 2 and 3

11. In endochondral ossification, what is the original source of osteoblasts? De novo synthesis Cells brought via the nutrient artery Cells of the inner layer of the perichondrium Chondrocytes from the original model

12. How could X-rays of the femur be used to determine whether a person has reached full height? The epiphyseal plates can be identified. The epiphyseal lines can be measured. The width of the shaft can be correlated to height. The extent of osteoporosis can be seen.

13. How is bone remodeling accomplished? • Osteoblasts form new bone matrix. • Osteocytes remove and replace calcium salts. • Osteoclasts are not active, thus producing stronger bone. • 1 and 2.

14. Why were some people sickened by radioactivity years after the Chernobyl accident? • Osteoclasts do not differentiate between heavy metals and calcium • Turnover of bone matrix caused release of stored radiation into circulation • Osteoblasts are a type of memory cell and recall the poisons that enter them • Heavy metal ions are stored in the bloodstream

15. Why would you expect the arm bones of a weight lifter to be thicker and heavier than those of a jogger? Joggers are naturally thin. Larger muscles apply more mechanical stress to the bones. Aerobic exercise reduces bone mass. Anaerobic exercise reduces bone mass.

16. A child who enters puberty several years later than the average age is generally taller than average as an adult. Why? Epiphyseal plates fuse during puberty. Bone growth continues throughout childhood. Growth spurts usually occur at the onset of puberty. All of the above.

17. A seven-year-old child has a pituitary tumor involving the cells that secrete growth hormone (GH), resulting in increased levels of GH. How will this condition affect the child’s growth? The individual will be taller. The individual will be shorter. Growth of the individual will be erratic and slow. Excessivegrowth will be limited to axial skeleton.

18. Which hormone is correctly paired with its function? • Calcitonin/stimulates osteoclast activity • PTH/reduces calcium ion concentration of body fluids • Calcitrol/inhibits calcium and phosphate ion absorption along the digestive tract • Thyroxine/stimulates osteoblast activity

19. Why does a child who has rickets have difficulty walking? Joints become fused, preventing movement. Bones are brittle and break under body weight. Bones are flexible and bend under body weight. Motor skills are impaired.

20. What effect would increased PTH secretion have on blood calcium levels? Higher level of calcium Lower level of calcium Uncontrolled level of calcium No effect on blood calcium, PTH affects calcium in the bones

21. How does calcitonin help lower the calcium ion concentration of blood? By inhibiting osteoclast activity By increasing the rate of calcium excretion at the kidneys By increasing the rate of calcium uptake by intestinal cells 1 and 2

22. Why would a second fracture to a particular bone be more likely to occur at a different site along that bone than the first fracture? The newly formed bone is slightly thicker and stronger at the original fracture site. During healing of the first fracture, calcium was removed making the site of the second fracture weaker. The person is older when the second fracture occurs, so their bones are weaker. None of these is correct.

23. A balance between which two hormones is essential for maintaining calcium homeostasis? • Calcitrol and parathyroid hormone • Calcitrol and thyroxine • Calcitonin and parathyroid hormone • Growth hormone and sex hormones

24. Why are women usually shorter than men at maturity? • Estrogens cause faster epiphyseal plate closure. • Androgens cause faster epiphyseal plate closure. • Thyroxine increases the rate of osteoblast activity in boys before puberty. • Men have more growth hormone.

25. Why would you expect that all people lose some height as they age? • Osteomalacia causes the bones to soften. • Osteopenia causes a reduction in bone mass. • Osteoporosis causes a reduction in bone mass. • Growth hormone is no longer available.

26. Why is osteoporosis more common in older women than in older men? Testosterone levels decline in post-menopausal women. Older women tend to be more sedentary than older men. Declining estrogen levels lead to decreased calcium deposition. In males, androgens increase with age.