IDC Dive Physiology & Medical Considerations

Question 1

Which law explains why a diver's lungs can overexpand if they hold their breath during ascent?

Accepted Answer

Boyle's Law

Answer

Boyle's Law states that as pressure decreases, gas volume increases proportionally, so a breath held during ascent will expand and can rupture lung tissue.

Question 2

Type II (serious) decompression sickness (DCS) is distinguished from Type I primarily by the involvement of:

Accepted Answer

The nervous system, lungs, or cardiovascular system

Answer

Type II DCS involves serious neurological, pulmonary (chokes), or cardiovascular symptoms, while Type I is limited to pain and skin manifestations.

Question 3

A diver experiencing euphoria, impaired judgment, and slowed reaction time at depth is most likely suffering from:

Accepted Answer

Nitrogen narcosis

Answer

Nitrogen narcosis, often called 'rapture of the deep,' causes narcotic effects similar to alcohol intoxication at depth due to elevated partial pressure of nitrogen.

Question 4

The primary recommended treatment for decompression sickness in the field before reaching a hyperbaric chamber is:

Accepted Answer

100% oxygen breathing

Answer

Breathing 100% oxygen at the surface accelerates nitrogen washout from tissues and helps reduce bubble size, making it the critical first aid for DCS.

Question 5

According to PADI standards, what is the maximum recommended ascent rate for recreational divers?

Accepted Answer

9 meters (30 feet) per minute

Answer

PADI recommends a maximum ascent rate of 9 meters (30 feet) per minute to allow adequate off-gassing and reduce decompression sickness risk.

IDC - Certified Instructor Development Course Trainer Practice Test

IDC - Certified Instructor Development Course Trainer Practice Test

IDC Dive Physiology & Medical Considerations