Identify the condition that will result in an increased level of calcium in the blood.

Question

A.  inhibition of chondrocytes
B.  excess osteocyte activity
C.  excess osteoblast activity
D.  inhibition of chondroblasts
E.  excess osteoclast activity

Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?

Gather Content
· What do you know about bone metabolism and calcium? What other information is related to the question?

Choose Answer
· Given what you now know, what information is most likely to produce the correct answer?

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

E.  excess osteoclast activity

Clarify Question
· What is the key concept addressed by the question?
        o The question asks about release of calcium into the blood.
· What type of thinking is required?
        o You are being asked to apply your knowledge of bone metabolism to explain an increase in calcium in the blood.

Gather Content
· What do you know about bone metabolism and calcium? What other information is related to the question?
        o Chondroblasts form cartilage and become chondrocytes or cartilage cells. Osteoblasts are bone-forming cells. When an osteoblast becomes trapped in the bone matrix it is constructing, it becomes an osteocyte, or bone cell. Osteoblasts arrange themselves along collagenous fibers in the bone and begin to secrete the enzyme alkaline phosphatase, which causes calcium phosphate salts to form in a crystalline configuration called hydroxyapatite. The crystals give the bone its hardness, but without the resilience afforded by collagen’s stretching ability, bone would be rigid but dangerously brittle. Typical bones have roughly equal volumes of collagen and hydroxyapatite, but hydroxyapatite contributes about 65% to the bone’s weight. Osteoclasts have the opposite functions as osteoblasts, and break down bone matrix, releasing calcium into the blood.

Choose Answer
· Given what you now know, what information is most likely to produce the correct answer?
        o The correct answer is that osteoclasts break down bone matrix, releasing calcium that was in the bone into the blood. Chondroblasts and chondrocytes are involved in cartilage production and will not affect calcium in the blood. An increase in osteoblast or osteocyte activity would pull more calcium from the blood into the bone that is being made.

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        o This question asked you to apply your knowledge of bone metabolism to explain an increase in calcium in the blood. If you got the correct answer, great job! If you got an incorrect answer, where did the process break down? Did you think that increased osteoblast or osteocyte activity would break down bone and release calcium? Did you think that decreased cartilage production would increase blood calcium?