36 Questions
What is the primary cause of tissue ischemia in decompression sickness?
Formation of gas bubbles in blood vessels
What percentage of individuals experiencing decompression sickness exhibit nervous system symptoms?
5%
How does hyperbaric oxygen therapy help treat acute decompression sickness?
It forces the gas back into solution
Why is helium usually used in the gas mixture instead of nitrogen for very deep dives?
Helium diffuses out of tissues during decompression faster than nitrogen, reducing decompression sickness risk.
How does the low density of helium impact breathing during very deep dives?
It minimizes airway resistance, which is beneficial for deep dives.
What would happen if the oxygen concentration in the gaseous mixture for deep dives is not reduced?
It would elevate the risk of oxygen toxicity due to elevated partial pressures of O2.
What is a characteristic of nitrogen narcosis that makes it similar to alcohol intoxication?
Decreased cognitive function
At what depth do divers develop symptoms of becoming drowsy due to nitrogen narcosis?
150 feet
How does the nitrogen dissolved in the body tissues affect the body when a diver breathes air under high pressure for a long time?
It increases in body fluids
What happens if a diver suddenly ascends to the surface of the sea after breathing air under high pressure?
Formation of nitrogen bubbles in the body fluids
What method is used by divers to equalize pressure and hear ears pop?
Holding the nose and trying to blow out
At what depth beneath the ocean surface is a person exposed to 3 atmospheres of pressure?
66 feet
Which law describes the compression of gases to smaller volumes as a diver descends beneath the sea?
Boyle's Law
What can increased pressure at depth do to the air chambers in a diver's body?
Collapse them
What fraction of air is nitrogen, which can cause nitrogen narcosis at high pressures?
Four fifths
How does increased pressure affect the volume of gas at a depth of 33 feet beneath the sea?
Compressed to one-half liter
What is the unit of atmospheric pressure mentioned in the text?
Pascal
In terms of pressure, why is the absolute pressure in a bicycle tire higher than the gauge pressure?
The absolute pressure includes the atmospheric pressure.
Why does the pressure in the feet of a standing person exceed the pressure at the heart?
Gravity causes a higher blood column in the feet.
What happens to blood pressure as it travels from the heart to small veins?
Decreases significantly
How does inspiration (breathing in) affect the pressure in the body compared to atmospheric pressure?
Decreases below atmospheric pressure
What does the equation p=ρ gh represent in relation to pressure?
Pressure due to depth in a fluid
Why is it essential to measure blood pressure differences in the circulatory system?
To understand blood flow dynamics
What can cause tissue ischemia or tissue death in decompression sickness?
Gas bubbles blocking blood vessels
What percentage of individuals with decompression sickness experience paralysis or unconsciousness due to nervous system symptoms?
3%
How is acute decompression sickness initially treated?
High-pressure chambers
What could happen if obstructed gas bubbles are not forced back into solution in decompression sickness treatment?
Formation of more gas bubbles
Which symptom is NOT commonly associated with decompression sickness?
Coughing
Why does it take many minutes to hours for bubbles to appear in decompression sickness?
Gas remains dissolved in a supersaturated state
What is the primary goal of hyperbaric oxygen therapy in treating decompression sickness?
Force gas back into solution
What is a potential consequence of nitrogen narcosis at 200 to 250 feet for a diver?
Experiencing significant clumsiness
Why does nitrogen remain dissolved in all body tissues when a diver breathes air under high pressure for a long time?
Because nitrogen is not metabolized by the body
What happens if nitrogen bubbles develop extracellularly in the body fluid of a diver returning suddenly to the surface of the sea?
The bubbles can plug many small blood vessels
Why is decompression sickness referred to as multiple problems collectively?
As it involves various symptoms and complications
What is the primary reason helium is preferred over nitrogen for very deep dives?
Nitrogen poses a higher risk of decompression sickness
How does nitrogen narcosis at 150 to 200 feet typically manifest in a diver?
Development of drowsiness
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