Biomedical Engineering 403

1997 Respiratory Section Exam Answers

Hi folks!

El Duggo here. My guess is that a few people are going to want me to regrade their exams. This is fine: it's quite possible that I may have missed something here or there grading and doling out partial credit for 1,792 questions. What I try to discourage is folks who just WANT more points, but can't really justify any reason why I should give it to them. So, here's the deal:

• If I added up the points on your test incorrectly, I will be HAPPY to go over it again and fix it. This is no problem.
• If I marked a question wrong when it was unambiguously right,(e.g., the answer was "true," you marked "true," and I said "NO! YOU'RE WRONG! THE ANSWER IS 'TRUE!' BE SAD!" and docked you points for it) then I was clearly having a stroke while I was grading your test, and will be happy again to fix this, with no hassle.
• If you got a question wrong, but showed your work, and feel you received inadequate partial credit, bring the test to me. I will regrade the entire exam, and assign you a new grade. Because the entire exam is being regraded, your final score may be higher, lower, or the same as your original score. Now, I'm pretty formulaic about partial credit - if you showed the equation, you get X points, if you filled in the right data, you get Y points, etc. So if you did show your work, and your mistake was a pretty minor one, you should have most of the points for that question. For people who DID show their work, and who only made minor math boo-boos, and who got only a tiny bit of partial credit, it will probably be beneficial to ask for a regrade. For people who did not show much work, made big boo-boos (e.g., using the wrong equation), and received a large amount of partial credit, it will probably be beneficial NOT to ask for a regrade.

  While I like to return the original exams as soon as possible, I usually take longer with regrades, because at that stage you've already learned what you could from the exam, and you already have a ballpark idea of what your grade is, so there's no emergent rush to return your exams again. But fear not -- your exam will be regraded.

• If you got a question wrong, but did not show any work, I cannot give you partial credit.

I love giving out points. That's why I think partial credit is a wonderful thing. I love giving out partial credit. I prefer it when people get the right answer, because it makes me feel happy and warm, and takes a whole lot less time to mark an answer correct than to assign partial credit, but hey, partial credit is good. But you've gotta give me valid justification. You have to have done the work. I love valid justification. I love it when you show the work. 'Cause then I can give you partial credit. I love partial credit.

Happy day.

1.

• (a) 5.51 Liters
• (b) 5.50 Liters. There is essentially no difference.
• (c) No Effect. This should be intuitive: Vital Capacity is the measure of how much your lungs can contain at maxmimum inhalation. This does not change with altitude.

2. {10} (True/False):

• (a) False
• (b) True
• (c) True
• (d) True
• (e) True

3.

• (a)
  

       F  V   =  F  V    +  F  V 
        E  T      I  D       e  A 
  

• (b)
  

  V  =  (F  -  F  ) / ( F   -   F  ) * V  
          E     e        I       e      T
  

• (c) 232.14 mL

4.

• (a) 80 mmHg
• (b) 50 mmHg
• (c) 50 mmHg or 6.58%

5. (c) both.

6.

• (a) Decreases pH
• (b) PCO2
• (c) Renal Compensation (also acceptable: Metabolic Compensation)
• (d) Yes (or decreases pH)

7.

(c) Prevent collapse of alveolus

8.

• (a) diaphragm
• (b) Alveolar
• (c) elastic
• (d) Yes

9.

• (a) (4) all of them.
• (b) PCO2
• (c) No, BECAUSE PO2 is most sensitive when both are abnormal (or integrated response). (Also acceptable: Ventilation increase is gradual, and does not become dramatic until PO2 drops to about 50 mmHg).

10.

• (a) Same
• (b) No
• (c) No, BECAUSE there is no arterial "error" in the feedback loop to initiate a ventilation response.

No!
Please don't make me go to any of those pages!
I want to go somewhere completely different!