Dive Physiology & Medical Considerations Flashcards

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

Answer: Boyle's Law

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.

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

Answer: The nervous system, lungs, or cardiovascular system

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

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

Answer: Nitrogen narcosis

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

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

Answer: 100% oxygen breathing

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

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

Answer: 9 meters (30 feet) per minute

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

Which physiological law explains why a diver must breathe more gas molecules per breath at greater depths to fill their lungs?

Answer: Dalton's Law

Dalton's Law of partial pressures explains that at depth, ambient pressure increases, so lungs must receive proportionally more gas molecules to maintain normal volume.

A diver performing repetitive dives needs to account for residual nitrogen primarily because:

Answer: Residual nitrogen from prior dives adds to nitrogen absorbed on subsequent dives

Residual nitrogen remaining in tissues from previous dives adds to nitrogen absorbed during subsequent dives, increasing DCS risk if not accounted for in dive planning.