Final Examination |
April 21, 1999. |
D. Stashuk |
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Answer 25 of the 30 questions in the examination booklets provided.
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No aids allowed
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Measurement and Instrumentation Systems
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2 Questions (4 marks each Total 8):
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1. Briefly, discuss some of the affects of two different technologies, which have been developed in the 20th century, on health care delivery.
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2. Briefly, discuss some of the major factors that need to be considered when obtaining measurements from a living system.
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Physiology of Excitable Cells and the Origin of Biopotentials
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4 Questions (4 marks each Total 16):
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3. Briefly, describe the structure of the membrane of an excitable cell.
Include the elements and aspects of the membrane that allow the cell to be excitable.
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4. Briefly, explain the creation of a Nernst potential.
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5. What aspects of an excitable cell determine its membrane potential?
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6. Briefly, explain why the amplitude of a current pulse, required to elicit an action potential in an excitable cell, decreases as it duration increases.
Also, explain why there is a minimum amplitude for the current pulse, even if it is infinitely long.
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Biopotential Electrodes
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2 Questions (4 marks each Total 8):
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7. Why are nonpolarizable electrodes so widely used?
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8. Briefly, describe the fundamental principles of operation of a carbon dioxide electrode.
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Skeletal Muscle System
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5 Questions (4 marks each Total 20):
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9. Briefly, compare and contrast skeletal and cardiac muscle fibres.
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10. Briefly, describe muscle spindles and their role in peripheral muscle control.
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11. Briefly, describe the composition of a motor unit action potential.
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12. Briefly, discuss how characteristics of needle detected motor unit action potentials can be used to determine the state of health of a specific muscle.
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13. Briefly, describe how and why EMG signals can be detected and processed to measure muscle force.
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Central Nervous System
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5 Questions (4 marks each Total 20):
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14. Briefly, describe the basil ganglia, its location and primary function.
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15. Briefly, what can be the affect of injury to the spinal cord and why?
What determines the extent of the affect of a spinal cord injury?
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16. Briefly, compare and contrast EEG and EMG signals.
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17. Briefly, discuss how and why EEG signals can be used?
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18. How are auditory evoked potentials obtained?
How can they be used?
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Cardiovascular System
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6 Questions (4 marks each Total 24):
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19. Briefly, explain why the left ventricle of the heart is much bigger and stronger than the right ventricle.
Briefly, explain the purpose and operation of the valves of the heart.
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20. Briefly, explain why SA node cardiac fibres have the shortest refractory period.
What are some of the consequences of an improperly functioning AV node?
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21. Briefly, discuss one method for measuring cardiac output.
Include some of the advantages and disadvantages of the technique discussed.
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22. Briefly, describe the major components of an ECG waveform and what cardiac activity they are related to.
How can these components can be used clinically?
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23. What is considered competitive stimulation by a cardiac pacemaker?
Why is competitive stimulation potentially unsafe and how can it be avoided?
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24. Why are cardiac pacemaker electrodes as small as possible, while cardiac defibrillator electrodes are as large as possible?
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Medical Imaging
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6 Questions (4 marks each Total 24):
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25. What are two different methods of controlling the intensity of X-rays created by an X-ray tube?
Which of these two methods is used to create diagnostic X-ray and why?
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26. Briefly, explain why contrasting substances such as barium sulphate are used to obtain X-ray images of the gastro-intestinal tract.
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27. Briefly, describe how X-ray CT scans are obtained and what determines their resolution.
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28. Briefly, explain the spin warp (phase encoding) method of obtaining MR images.
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29. Briefly, explain what factors determine the thickness of the tissue layer contributing to an MR image.
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30. Briefly, explain the sequence of excitation pulses required to use both the spin-lattice and spin-spin relaxation properties of a tissue to obtain contrast in an MR image.
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