Extremes

• Are liquid areas of the body resistant to effects of high pressure?

  Relatively resistant
• When do problems arise due to air spaces in the body under pressure?

  When gas pressures can't equilibrate
• What type of injury arises from pressure changes?

  Barotrauma
• What part of the body has issues if the eustachian tube is blocked?

  Ears
• Why does a blocked eustachian tube cause ear problems during diving?

  It prevents gas movement to the middle ear
• At what depth do symptoms of nitrogen narcosis typically appear?

  30m
• At what depth can nitrogen narcosis be fatal?

  90m
• Why does the concentration of dissolved N2 in the blood increase with depth?

  Because depth increases pressure
• Why does nitrogen have a high solubility in lipid compared to blood?

  Due to its molecular structure
• What does nitrogen act like at increased depths?

  A volatile anesthetic
• How does nitrogen alter ion conductance at depth?

  By acting like an anesthetic
• What is a symptom of nitrogen narcosis?

  Confusion
• What is a symptom of nitrogen narcosis?

  Sleepiness
• What is a symptom of nitrogen narcosis?

  Tunnel vision
• What is a symptom of nitrogen narcosis?

  Dizziness
• What is a symptom of nitrogen narcosis?

  Euphoria
• How can nitrogen narcosis be prevented during diving?

  Limit depth and dive duration
• How can nitrogen narcosis be prevented during diving?

  Replace N2 with Helium in gas mixture
• Why is Hb almost fully saturated even at atmospheric pressure?

  Because of its binding affinity to oxygen
• What happens to extra O2 when pressure increases?

  It is dissolved in the plasma
• At what depth is oxygen partial pressure equivalent to breathing 100% O2 at sea level?

  40m (5atm)
• What is the problem with long term exposure to high oxygen partial pressures?

  Respiratory tract damage
• What is the problem with long term exposure to high oxygen partial pressures?

  Possible CNS problems
• What can breathing air at 90m (10atm) lead to?

  Seizures and coma
• What causes some problems associated with oxygen toxicity?

  Increased levels of free radicals
• How can oxygen toxicity be resolved?

  Reduce oxygen concentration
• What is a potential problem during ascent in diving?

  Lung over inflation
• What is a potential problem during ascent in diving?

  Pneumothorax
• What is a potential problem during ascent in diving?

  Mediastinal emphysema
• What is a potential problem during ascent in diving?

  Subcutaneous emphysema
• What causes decompression sickness?

  N2 build up in tissues
• How can decompression sickness be overcome?

  Slow return to normal pressures
• What type of decompression sickness is linked to pains in muscles and joints?

  Type 1 DCS
• Which type of DCS is more serious?

  Type 2 DCS
• What body systems are affected by Type 2 DCS?

  CNS, lungs, CVS, and blood
• What must submariners do to avoid lung damage when escaping a submarine?

  Exhale during ascent
• Why does DCS risk increase with depth during submarine escape?

  Because of higher N2 absorption
• What is the standard atmospheric pressure in mmHg?

  760mmHg
• What percentage of dry atmospheric air is nitrogen?

  78.09%
• What percentage of dry atmospheric air is oxygen?

  20.95%