Henry is a 65-year-old man who was admitted to the emergency room after a fall. A radiograph confirmed that he had fractured the proximal part of his humerus. The radiograph also revealed that his bone matrix was not as dense as it should be for a man his age. A test for blood Ca2 was normal. On questioning, Henry confessed that he is a junk food addict who eats few vegetables and never consumes dairy products. In addition, Henry never exercises and seldom goes outdoors, except at night.
Use your knowledge of bone physiology and process figures from the textbook to answer the following questions.
1.Why is Henry more likely to break a bone than are most men his age?
2.How have Henry’s eating habits contributed to his low bone density?
3.Would Henry’s PTH levels be lower than normal, normal, or higher than normal?
4.What effect has Henry’s nocturnal lifestyle had on his bone density?
5.How has lack of exercise affected his bone density?
6. What are the homeostatic mechanisms that maintain normal bone density?