100b: BENG Frontiers in Biomedical Engineering Spring 2008 FINAL EXAMINATION May 7, 2008
INSTRUCTIONS: You have three hours to complete this exam. This is a closed book exam. You may use a calculator. Only work shown in the space provided will be graded. Partial credit will be given when warranted. The exam is worth a total of 100 points.
Instructor: Mark Saltzman Department of Biomedical Engineering Yale University
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Question 1. (20 points) Cardiovascular physiology As you know from our section meeting, blood pressure is measured using an inflatable cuff and a stethoscope. Describe how this blood pressure measurement works by answering the following questions: a) What happens in your arm as the inflatable cuff is pressurized? Why is it usually inflated to ~200 mmHg?
b) Blood pressure is recorded as (systolic pressure)/(diastolic pressure), with a typical value of 120/80 (in mmHg). These pressures are determined by listening with a stethoscope as the pressure in the cuff is decreased. What physical process creates the sounds?
c) How are pressures measured in the arm related to pressures in the heart?
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Question 2. (20 points) Renal Physiology The nephron is the functional unit of the kidney. a) Describe the structure of the nephron, using a diagram, if you like.
b) Describe an experimental approach for measuring the glomerular filtration rate using the tracer molecule inulin.
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Question 3. (20 points) Tissue Engineering Many people believe that tissue engineering may someday offer an alternative patients for who now can only by treated by whole-organ transplantation. List three other possible uses for tissue engineering and provide an example of each.
Tissue engineering strategies can generally be divided into 2 categories; cell-based and biomaterial-based. Discuss the strengths and weaknesses of each approach using examples from the lectures and address some of the challenges of integrating the two approaches.
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Question 4. (20 points) Biomechanics a. A bird in flight (or an airplane in flight) experiences forces that move it in a forward direction and that keep it aloft. Draw a diagram showing the forces that are acting on a bird (or airplane) that is moving forward at a constant velocity and maintaining a constant altitude. b. Label the forces in the diagram.
c. What physical mechanisms does a bird use to generate the forces necessary to move forward and stay aloft?
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Question 5. (20 points) Imaging a) What is ionizing radiation?
b) Ionizing radiation from a variety of sources is used for creating images in humans. Select any two sources of ionizing radiation and describe a method for imaging based on that type of radiation.
c) Ultrasound imaging does not involve ionizing radiation. What physical principle does it use? How is an image created using this principle (i.e. what properties of tissues does it detect)?
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Bonus. (10 points) Describe one interesting biomedical engineering principle that you learned from reading the research papers prepared by your peers.
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