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Questions and Answers on
Physiology and Medical Aspects of Scuba Diving


Lawrence Martin, M.D. Copyright 1997


Buy the book
Scuba quiz
Myths & Misconceptions
Disclaimer & Invitation

Brief History of Diving
Recreational  Diving
The Respiratory System
Explanation of Pressure

Water & Physical Laws
Unequal Air Pressures
Decompression Sickness
Oxygen Therapy
Gas Pressure at Depth

Dive Tables & Computers
Stress & Diving
Non-air Gas Mixtures
Women & Diving
Medical Fitness for Diving
Asthma & Diving
The Great Debate

All About DAN
Scuba Training Agencies
Magazines & Newsletters
Books & Videos

Diving Odds N' Ends

Internet Links

Short Scuba Quiz

For each of the following 15 multiple-choice questions choose the SINGLE BEST ANSWER. Answers are at the end of the quiz. If you answer 12 or more questions correctly, you already know quite a bit about scuba diving. After the multiple choice quiz is a "Trivia" quiz based on other information in the book.

1. The gas composition of ordinary air is:

a) 15% oxygen, 20% nitrogen, 5% other
b) 20% oxygen, 75% nitrogen, 5% other
c) 21% oxygen, 78% nitrogen, 1% other
d) 24% oxygen, 79% nitrogen, 3% other
e) 26% oxygen, 81% nitrogen, 3% other

2. Compressed air in a scuba tank filled to capacity, compared to ordinary arie, has:

a) the same composition
b) a greater percentage of oxygen
c) a greater percentage of nitrogen
d) a greater percentage of both oxygen and nitrogen
e) varying composition of oxygen and nitrogen, depending on the tank pressure

3. Compared to seal level ai pressure, aire pressure ina scuba tank with 3000 psi is approximately how many times higher?

a) 10
b) 50
c) 100
d) 200
e) 400

4. The total number of atmospheres of pressure on a scuba diver at 99 feet of sea water is:

a) 2
b) 3
c) 4
d) 5
e) 6

5. Nitrogen narcosis ("rapture of the deep") results from:

a) nitrogen forming bubbles in the nervous system
b) lack of oxygen to the brain from excess nitrogen pressure
c) a direct effect of high nitrogen pressure on the nervous system
d) diving with an elevated blood alcohol level
e) staying too long under water

6. Which of the following problems is least related to diving deeper than allowed by standard dive tables?

a) nitrogen narcosis
b) type I decompression sickeness (pain only, or "the bends")
c) type II decompression sickness (major physical deficit, such as paralysis)
d) air embolism
e) running out of air

7. The reason scuba divers should never hold breath under water has to do with effects explained by:

a) Boyle's law
b) Daltons's law
c) Henry's law
d) lack of oxygen that occurs when you stop breathing
e) the buildup of carbon dioxide when you stop breathing

8. At a depth of 66 feet sea water, air breathed from a scuba tank as it enters the diver's lungs is how much denser than air breathed at seal level?

a) same density
b) twice as dense
c) three times as dense
d) four times as dense
e) depends on amount of air left in scuba tank at that point

9. Wich one of the following factors is the same for aire embolism and for decompression sickness?

a) composition of the gas bubbles
b) principal location of gas bubbles in the body
c) cause of the bubbles
d) time of onset of symptoms in relation to the end of the dive
3) method of treatment

10. Aire embolism occurs on:

a) descent only
b) ascent or descent, depending on where the diver holds his or her breath
c) ascent or descent, depending on where the diver runs out of air
d) ascent only, and only with breath holding
e) ascent only, and depends on factors such as breath holding and state of the diver's lungs

11. "Shallow-water-blackout," as may be seen in breath-hold dives, is due to:

a) elevated carbon dioxide from prolonged breath holding
b) lack of oxygen from prolonged breath holding
c) both elevated carbon dioxide and lack of oxygen
d) nitroten buildup from prolonged time under water
e) siezures brought on by the breath hold in susceptible people

12. First aid treatment for a victim of decompression illness should always include 100% inhaled oxygen because:

a) it stimulates the heart to pump harder
b) it hastens the elimination of nitrogen
c) it hastens the elimination of carbon dioxide
d) it helps to keep victoms from hyperventilating
3) the victim's blood is usually low in oxygen

13. All of the following are forms of barotrauma except one:

a) pneumothorax
b) mask squeese
c) air embolism
d) the bends
e) ear squeeze

14. Dive table s are based on the assumption that:

a) the diver will make no more than three dives a day
b) all bottom time is spent at the deepest depth reached
c) the survace interval will be at least one hour between dives
d) any subsequent dive will be shallower than the one before
e) there will be no multi-level diving

15. The principal reson peoplewith asthma are advised not to dive is the risk of

a) the bends
b) running out of air due to over breathing
c) arterial gas embolism
d) an asthma attache from breathing dry compressed air
e) aspirating sea water from caughing at depth


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