Transcript Physiological Divisions

Physiology of Flight
Objective: Know the physiology of flight.
Physiology of Flight: Overview
• Nature of the Atmosphere
• Respiration and Circulation
• Effects of Reduced Pressure at Altitude
• Rapid Decompression
Nature of the Atmosphere
 Composition of the atmosphere
• 78% nitrogen, 21% oxygen,
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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.
Nature of the Atmosphere
Physiological Divisions
• Physiological zone
 Extends from sea level to 10,000 ft
• Physiological-deficient zone
 Extends from 10,000 to 50,000 ft
• Space-equivalent zone
 Extends from 50,000 feet to 120
miles above Earth
• Total space-equivalent zone
 Beyond 120 miles above Earth
Boyle’s Law
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The volume of a gas varies exactly
opposite that with the pressure of a gas.
A decrease in volume causes an
increase in pressure
An increase in volume causes a
decrease in pressure
Gas
Pressure
14.7 psi
29.4 psi
58.8 psi
Dalton’s Law
• The total pressure of a mixture of gases
is equal to the sum of the partial pressure
of each gas in that mixture.
Henry’s Law
• The amount of a gas in a solution
varies directly with the partial
pressure that gas exerts on the
solution.
Respiration and Circulation
 Respiration is the exchange of oxygen and carbon dioxide
between an organism and its environment.
• At rest, on average we breath
15-18 times a minute exchanging
about 500 ml of air
• Oxygen is taken into the body
through the airways, absorbed into
the lungs, then transported through
the body in the blood. The lungs also
give out carbon dioxide into the
atmosphere.
Respiration and Circulation
 If the Respiratory System
captures and transports oxygen
throughout the body as well as
removes carbon dioxide….what
happens as the air pressure with
altitude decreases?
Respiration and Circulation
 Less Oxygen available for the
respiratory system to capture –
result?
 Hyperventilation: Increased
rapid breathing
 Hypoxia: Occurs when tissues in
the body do not receive enough
oxygen.
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Possible Symptoms (vary with
individual):
Headache, decreased reaction time,
impaired judgment, euphoria, visual
impairment, drowsiness, lightheaded
or dizzy, tingling, numbness, blue
fingernails and lips, limp muscles
Effects of Reduced Pressure at Altitude
 Trapped Gases-Ear Block
• Trapped Gases-Tooth Pain
Valsalva Maneuver
Effects of Reduced Pressure at Altitude
 The Bends
• Release of nitrogen into
the joints of the body.
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.
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.
Rapid Decompression
 Rapid decompression at a high altitude brings on an explosion
as the pressure suddenly decreases.
 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.
Time of Useful Consciousness
Altitude
45,000 feet
40,000 feet
35,000 feet
30,000 feet
28,000 feet
25,000 feet
22,000 feet
20,000 feet
MSL
MSL
MSL
MSL
MSL
MSL
MSL
MSL
TUC
9 to 15 seconds
15 to 20 seconds
30 to 60 seconds
1 to 2 minutes
2.5 to 3 minutes
3 to 5 minutes
5 to 10 minutes
30 minutes or more
Physiology of Flight
Objective: Know the physiology of flight.