Ph.D. >> Exams >> Sample Questions
This sample of questions has been asked in the past and are representative of the material that a student may be expected to discuss. It is not exhaustive.

1. Derive the Navier-Stokes equations. Explain their application and the significance of each term to blood flow in : (i) heart (ii) large arteries (iii) microvessels (iv) veins.
2. Describe and explain with equations: (I) the "vascular waterfall" (ii) flutter in veins.
3. Describe, giving values and equations, the significance of the following dimensionless quantities in blood flow : (i) Reynold’s number (ii) The Wormersly number.
4. Strains in soft tissues may be large. What are the appropriate measures? Define them mathematically. Why are the linear Cauchy strains not exact? Give an example. What are the differences between Lagrangian and Eulerian description in mechanics? What is the kinematic incompressibility constraint?
5. Describe the mechanical properties of a typical soft biological tissue. Formulate a constitutive equation.
6. Outline the changes in left ventricular pressure and volume during the cardiac cycle. How would you measure these in an experimental animal? In a patient? What is the stroke work? How does it relate to myocardial oxygen consumption? To myocardial blood flow?
7. Define "aortic impedance" using the "Windkessel" model.
8. Formulate a mathematical theory of blood flow in large blood vessels. How does it differ from a corresponding theory for the flow of plasma (not red cells) only? Describe the Fahraeus-Lindqvist effect and provide its explanation.
9. Derive an equation for pulse wave propagation in an elastic vessel. What is the wave speed?
10. Draw the isometric length-tension curve for: (i) skeletal muscle (ii) cardiac muscle.Explain in terms of the sliding filament theory. Why are cardiac and skeletal muscle different? What is the basic mechanism of excitation-contraction coupling? What is the energy source for muscle contraction?
11. What are the mechanisms by which large, medium size and small molecular species are carried from the blood stream into the tissue?
12. Formulate a mathematical theory for oxygen transport in the muscle microcirculation. Describe its key features.
13. Under what conditions is metabolism of small molecules limited by convection, diffusion or reaction? Large molecules? Why?
14. What parameters characterize a membrane in an osmotic system?
15. What is the value of tissue pressure in normal tissues?
16. Define and describe in words the chemical potential of solution.
17. Give examples (3 or more) of forces that cause the motion of matter.
18. What is the electrosmotic effect?
19. Describe reflex mechanisms that are activated in the case of blood loss. Include a diagram of pathways.
20. Describe the autoregulatory mechanisms that control the peripheral circulation.
21. What information can be obtained from an electrocardiogram and what cannot? Give reasons for your answer.
22. Physically and mathematically describe facilitated transport of oxygen through a hemoglobin-containing membrane.
23. What is Taylor dispersion?
24. Describe the mechanism of signal conduction in a nerve.
25. What are the fundamental assumptions in modeling an electrical system as a lumped element circuit, and using Kirchoff’s voltage and current laws to analyze the circuit?
26. Compute the input and output impedance of a given circuit.
27. What is a linear, time-invariant system? How are the impulse and step-response of a system related to the system function and frequency response?
28. For an experimental system you are familiar with, how does one obtain and store data without losing information? (i.e., what should the sampling rate be, and what sort of filtering might be necessary?)
29. How does a glass pH electrode work, and what physical factors affect the probe output?
30. Describe some important cell adhesion molecules and where they are found. How is the mechanics of cell adhesion measured and modeled?
31. Give an example of how the viscoelastic behavior of single cells is measured and analyzed?
32. Describe one or more pathways via which cells respond to mechanical stimulation in vivo. How are these studied experimentally?
33. What is a proteoglycan? Give some examples; describe their structure; what functions do they play and where are they found?
34. What is meant by “cooperativity”?
35. Give an example of an “entropic spring”?
36. Explain how you would formulate a model of receptor-ligand interactions?
37. What is the structure and function of a gene?
38. How is the carbohydrate or fat you intake processed and utilized in driving energentically infavored reactions?
39. How are genetically engineered animal models created?