Physiology of Flight

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Physiology of Flight
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PRE-TEST
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VOCABULARY

• M-1 a maneuver to constrain your vessels and
  muscles to keep blood from rushing to your feet
  during G-loads

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PRE-TEST
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VOCABULARY

• Physiology the organic processes or functions
  in an organism or in any of its parts.

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VOCABULARY

• Hypoxia deficiency in the amount of oxygen
  delivered to the body tissues

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VOCABULARY

• Valsalva a maneuver to clear your ears to
  equalize pressure

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VOCABULARY

• M-1 a maneuver to constrain your vessels and
  muscles to keep blood from rushing to your feet
  during G-loads

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Nature of the Atmosphere

• Composition of the atmosphere
• 78 nitrogen, 21 oxygen, 1 carbon dioxide.
• Nitrogen is not used by body to support life.
• Blood and other body fluids contain nitrogen.
• Blood carries oxygen to all parts of the body.
• Oxygen decreases at higher altitudes.

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VOCABULARY

• TUC Time of Useful Consciousness
• 15,000 feet ?
• 22,000 feet ?
• 25,000 feet ?
• 35,000 feet ?
• 45,000 feet ?

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Physiological Divisions of the Atmosphere
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Physiological Divisions of the Atmosphere
Total Space-Equivalent Zone
Pressure
120 miles
Partial Space-Equivalent Zone
No Winged Flight
80,000
Armstrongs Line
63,000
87 mm Hg
50,000
(pressure breathing)
Physiological-Deficient Zone
10,000
583 mm Hg
14.7 psi
760 mm Hg
Sea level
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Nature of the Atmosphere

• Physical Laws of Gases
• Boyles Law
• The volume of a gas is inversely proportional to
  its pressure if the temperature remains constant.
• Daltons Law
• The total pressure of a mixture of gases is equal
  to the sum of the partial pressure of each gas in
  that mixture.
• Henrys Law
• The amount of a gas in a solution varies directly
  with the partial pressure that gas exerts on the
  solution.

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Respiration and Circulation

• Respiration is the exchange of oxygen and carbon
  dioxide between an organism and its environment.
• Closely related to circulation of blood
  throughout the body.

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Respiration and Circulation

• Decreasing oxygen pressure places stress on the
  body affecting the respiratory system first.
• Made up of the lungs, bronchi and their small
  branches, windpipe, mouth, and the nose.
• Air enters the nasal passages where it is warmed
  and moistened and foreign matter removed.

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Respiration and Circulation
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Respiration and Circulation

• The amount of carbon dioxide in the blood has an
  important effect on the action of the heart.
• As carbon dioxide in the blood increases, the
  heart rate speeds up so the heart can send more
  oxygenated blood to the tissues.
• When carbon dioxide in the blood decreases, the
  heart rate slows because tissues need less
  oxygen.

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Respiration and Circulation

• The respiratory system acts to keep the amount of
  oxygen in the body tissues constant.

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Effects of Reduced Pressure at Altitude

• As the body goes to high altitude it must make
  adjustments to the reduced atmospheric pressure
  in order to keep the body tissue constant. If
  the pressure outside the body is greatly reduced
  and the body is not adequately protected, it
  cannot make the necessary adjustments.

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Effects of Reduced Pressure at Altitude

• Hypoxia - a deficiency of oxygen in the body
  cells or tissue.
• Most frequently the result of decreased pressure
  on an unprotected body.
• In flight is usually caused by an insufficient
  amount of oxygen in the inhaled air.
• Greatest danger when pilot becomes engrossed in
  duties and doesnt notice the first symptoms.

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Normal Body Function Breathing

• For normal breathing, your body will breathe in
  the air around it.
• This air contains 21 oxygen, 78 nitrogen, and
  other trace elements.
• Normally, your blood has a concentration of 75
  of oxygen.
• Your lungs will add more oxygen to it, so when
  the blood reaches your brain, it has 98
  saturation of oxygen.

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Pilots are at the greatest risk!

• The air maintains the same concentration of
  elements at any height.
• The reason you have difficulty breathing at
  higher altitudes is the drop in atmospheric
  pressure.
• Your lungs are unable to draw in enough air to
  maintain the oxygen levels that you need.

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Ready For Takeoff!
At takeoff, your body is pulling 21 oxygenated
air into your lungs to change the 75 of the
oxygen saturated in your blood to 98 saturation
for your brain.
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Going UP!
But, air pressure is 25 less
The lower oxygen levels to your body begins to
affect your night vision and your ability to
handle new tasks.
When the altitude increases to 8,000 feet, your
body still pulls 21 oxygenated air into your
lungs. But, your blood has 65 oxygen
saturation that becomes 95 saturated for your
brain.
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Still going UP!
But, air pressure is 45 less
The lower oxygen levels to your body reduces your
physical capacity and impairs skilled task
performance.
When the altitude increases to 15,000 feet, your
body still pulls 21 oxygenated air into your
lungs. But, your blood has 55 oxygen
saturation that becomes 80 saturated for your
brain.
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Still going UP!
But, air pressure is 65 less
The lower oxygen levels to your body shows
obvious physical and mental impairment, and can
lead to unconsciousness.
When the altitude increases to 25,000 feet, your
body still pulls 21 oxygenated air into your
lungs. But, your blood has 35 oxygen
saturation that becomes 60 saturated for your
brain.
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Coming back DOWN!
But, air pressure is 75 less
The lower oxygen levels to your body rends you
incoherent in seconds and causes a complete loss
of consciousness.
When the altitude increases to 35,000 feet, your
body still pulls 21 oxygenated air into your
lungs. But, your blood has 25 oxygen
saturation that becomes 50 saturated for your
brain.
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Flying Right At Any Height!
With the altitude at 35,000 feet, the air
pressure is still 75 less than at sea level.
However, added oxygen through a mask can
supplement what the lungs are unable to breathe
in.
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Effects of Reduced Pressure at Altitude

• Hyperventilation
• A person affected by hypoxia tends to increase
  breathing rate in an attempt to take in more
  oxygen.
• May result from great emotional tension or
  anxiety.

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Effects of Reduced Pressure at Altitude

• Trapped Gases-Ear Block

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Effects of Reduced Pressure at Altitude

• Trapped Gases-Sinus Block

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Effects of Reduced Pressure at Altitude

• Trapped Gases-Tooth Pain
• Untreated cavities where pulp is exposed may be
  the cause of tooth pain at altitude.
• The toothache often disappears at the same
  altitude that if was first observed on ascent.
• Gases may be trapped in the teeth at altitude in
  abscesses.

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Effects of Reduced Pressure at Altitude

• Trapped Gases-Stomach and Intestines
• In flights above 25,000 feet the expanding gases
  may cause severe pain, lowering blood pressure
  and eventually shock.
• Usually air that has been swallowed.
• When barometric pressure falls the partial
  pressures of the gases in the body fluids
  decrease.
• The escaping gases cause decompression sickness.

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Effects of Reduced Pressure at Altitude

• The Bends
• Release of nitrogen into
• the joints of the body.

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Effects of Reduced Pressure at Altitude

• The Chokes
• Another form of decompression sickness.
• Deep, sharp pains under the sternum.
• Increased expansion of the lungs causes the pain
  to increase.

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Effects of Reduced Pressure at Altitude

• Skin Symptoms
• Type of decompression sickness that involves
  sensations of the skin.
• Small bubbles of nitrogen under the skin produce
  itching, hot and cold feelings and tingling.
• The rash does not disappear with descent and may
  last for hours.

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Effects of Reduced Pressure at Altitude

• Treatment of Decompression Sickness
• As decompression sickness becomes more severe,
  the pain caused by escaping gas bubbles becomes
  more intense.
• As symptoms appear in flight, 100 oxygen should
  be administered.
• If symptoms still exist after landing,
  compression therapy will be administered at the
  nearest hyperbaric facility.

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Rapid Decompression

• Rapid decompression at a high altitude brings on
  an explosion as the pressure suddenly decreases.
• At 63,000 feet or above body fluids boil if
  exposed to the ambient atmosphere.
• The time of useful consciousness may be reduced
  by 60 if the decompression is rapid and the air
  is forced out of the lungs due to rapid expansion.

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Principles and Problems of Vision
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Principles and Problems of Vision
Color Blind Test
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Principles and Problems of Vision
Aspen at Night
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Spatial Disorientation and Motion Sickness

• Spatial disorientation - the inability to
  accurately orient yourself with respect to the
  Earths horizon.
• We use four sensory systems to maintain our
  orientation and equilibrium (balance).

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Spatial Disorientation and Motion Sickness

• The Visual System
• Eyes provide the strongest and most reliable
  orientation information during flight.
• When the horizon is not correct, your vestibular
  disorientation disappears you may still
  experience visual illusions caused by false
  horizon.

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Spatial Disorientation and Motion Sickness

• The Vestibular System

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Spatial Disorientation and Motion Sickness

• The Vestibular System

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Spatial Disorientation and Motion Sickness

• The Somatosensory System
• Consists of tactile pressure receptors in the
  skin, muscles, tendons and joints.
• Often called the seat-of-the-pants sense.

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Acceleration and Deceleration Increased G-Forces

• When military flight crews perform maneuvers or
  when astronauts are launched or recovered they
  may be subjected to severe stress from the
  effects of acceleration and deceleration.
• The stresses are felt as increases in weight or
  gravity forces (G-Forces).

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Acceleration and Deceleration Increased G-Forces
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Noise and Vibration

• Cause flyers more inconvenience than any other
  factor in flight.
• Sound intensity or loudness is measured in
  decibels.
• Vibrations are measured in frequency.
• One effect of vibration is blurred vision.

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Heat and Cold During Flight

• The largest amount of heat is generated on the
  skin of aircraft and spacecraft as it travels at
  high speeds through the atmosphere.
• An aircraft flying at Mach 2 has skin
  temperatures increased by about 400o F as a
  result of aerodynamic heating.
• There are two dangers associated with exposure of
  the body to cold.

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Noxious Gases and Vapors

• Inside an enclosed cabin, noxious gases and
  vapors may accumulate.
• The breathing atmosphere can easily become
  contaminated from inside sources if care is not
  taken.
• Carbon Monoxide.

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Self-Imposed Stresses

• Alcohol
• One drink at 10,000 feet can have the same effect
  as two or three drinks at sea level.
• Tobacco
• Smoking at 10,000 feet produces effects
  equivalent to those experienced at 14,000 feet
  without smoking.
• Drugs
• Aspirin, nasal decongestants, tranquilizers or
  sedatives.

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Summary

• 1. Nature of the Atmosphere
• 2. Respiration and Circulation
• 3. Effects of Reduced Pressure at Altitude
• 4. Rapid Decompression
• 5. Principles and Problems of Vision
• 6. Spatial Disorientation and Motion Sickness

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Summary

• 7. Acceleration and Deceleration Increased
• G-Forces
• 8. Noise and Vibration
• 9. Heat and Cold During Flight
• 10. Noxious Gases and Vapors
• 11. Self-Imposed Stresses