Questions
Quick questions
You should be able to answer these questions without too much difficulty after studying this TLP. If not, then you should go through it again!
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Bone is a composite of a mineral which can be approximated to hydroxyapatite, and which protein?
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Which component of the hip implant is often made from ultra high molecular weight polyethylene?
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A titanium alloy is often used for the femoral stem component of the hip implant. Which other metals are present in this alloy?
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Fracture of bone occurs most easily:
Deeper questions
The following questions require some thought and reaching the answer may require you to think beyond the contents of this TLP.
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Which of these statement(s) is/are true?
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Which of these statement(s) is/are true?
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Hydroxyapatite has a density of 3.16 Mg m-3 and collagen's density is 1.33 Mg m-3. Using the weight percentages for dry bone given, calculate the volume fractions of bone mineral and collagen in cortical bone.
Use these volume fractions and the Young's Moduli of these components to calculate a value for the Young's modulus of dry cortical bone.
Explain any difference between this and the value quoted in the TLP. -
In this diagram of the top of a femur, the thickness of the cortical bone in the main shaft of the femur is marked.
This thickness is roughly 1 cm, with the marrow space located in the centre.
Using this diagram, make estimates of the maximum stress generated in the femur when
(A) standing still
(B) walking down stairs
( )