Underwater Human Physiology: Gas Laws, Risks, and Safety Strategies

At what pressure does the human body function optimally?

1 atmosphere (atm) of pressure at sea level.

How much does pressure increase in seawater with depth?

Approximately 1 atm every 10 meters of depth.

What is Boyle's Law?

Gas volume decreases as pressure increases.

What does Henry's Law state?

The amount of gas dissolved in a liquid increases with pressure.

What is Dalton's Law?

The total pressure of a gas mixture is the sum of the partial pressures of each gas.

What is barotrauma?

An injury caused by pressure differences damaging gas-filled spaces in the body.

What are common sites for barotrauma?

Ears, sinuses, and lungs.

What can cause lung barotrauma during ascent?

Holding one's breath, leading to tissue damage or air embolism.

What is nitrogen narcosis?

A neurological condition caused by increased nitrogen partial pressure.

What are symptoms of nitrogen narcosis?

Euphoria, impaired judgment, slowed reaction time, and reduced coordination.

What is decompression sickness, also known as 'the bends'?

A condition caused by dissolved nitrogen forming gas bubbles during rapid ascent.

What are the potential effects of decompression sickness?

Joint pain, fatigue, neurological damage, or paralysis.

What is oxygen toxicity?

A hazard that occurs when the partial pressure of oxygen is too high at depth.

What are the two forms of oxygen toxicity in diving?

Central nervous system toxicity and pulmonary oxygen toxicity.

How does water immersion affect the cardiovascular system?

It shifts blood from the limbs toward the chest, increasing central blood volume and cardiac output.

What is immersion diuresis?

Increased urine production due to fluid shifts toward the thorax.

What is High Pressure Nervous Syndrome?

A neurological condition that may occur during extremely deep dives.

What safety strategies do divers use to reduce risks?

Controlled ascent rates, decompression stops, dive planning, and specialized breathing gas mixtures.

What is the significance of understanding underwater physiology?

It is essential for safe diving and contributes to fields like environmental physiology and hyperbaric medicine.

What happens to breathing gas density as depth increases?

It becomes denser, increasing the work of breathing and may contribute to carbon dioxide retention.

What physiological response occurs due to thermal stress underwater?

Water removes heat from the body much faster than air.