Altitude Physiology Flashcards
What are the physical divisions of the atmosphere?
Troposphere - Extends to an Alt. of 30,000 ft. at the poles and 60,000 ft. at the equator Tropopause - boundary between troposphere and stratosphere Stratosphere - tropopause to about 50 miles upward. Ionosphere - end of stratosphere upward to 600 miles Exosphere - end of ionosphere to about 1200 miles (true space)
What are the physiological zones of the atmosphere
Efficient zone Deficient zone Space equivalent zone
Efficient zone
sea level to 10,000 ft
Deficient zones
10,000 ft to 50,000 ft
Space equivalent zone
above 50,000 ft
What are the functions of the circulatory system?
Transports O2 and nutrients to cells throughout the body Transports metabolic waste products to organ removal sites Assists in temperature regulation Acid-base balance
What carries O2 to cells
red blood cells
What are the functions of respiration?
Provide O2 to cells, Remove carbon dioxide from cells Assist in maintaining body temperature, Assist in maintaining body acid-base balance
Inhalation
The active phase of respiration. Movement of air into the lungs when the chest wall expands and the diaphragm moves downward.
Exhalation
The passive phase of respiration. Movement of air out of the lungs when the chest wall collapses and the diaphragm relaxes.
What happens to respiration during pressure breathing at altitude
The active and passive phases of respiration are reversed. In some indivduals, this can lead to hyperventilation and unconsciousness
Hypoxia
Oxygen deficiency sufficent to impair performance
What are the four types of Hypoxia
Hypemic Stagnant Histotoxic Hypoxic
Hypemic Hypoxia
Reduction in O2 carrying capability of red blood cells; e.g. carbon monoxide
Stagnant Hypoxia
Reduction in blood flow; e.g. positive G maneuvers
Histotoxic Hypoxia
Interference with the use of O2 by the body tissues; e.g. cyanide poisoning
Hypoxic Hypoxia
Insufficient pressure of O2 in the air; e.g. flying at altitude
Symptoms
What you feel
Signs
What you see in others
Stages of Hypoxia
- Indifferent stage
- Compensatory stage
- Disturbance stage
- Critical stage
(ICDC)
Indifferent stage
sea level to 10,000 ft, usually no symptoms noted in a healthy individual.
What is the only significant effect of mild hypoxia at the indifferent stage?
Night vision deteriorates at about 4,000ft.
Compensatory stage
10,000 to 15,000 ft;
mild effects begin to appear, but the individual can usually overcome the effects or compensate for the deficits
Disturbance stage
15,000 to 20,000 ft;
most of the symptoms of hypoxia will appear, and will increase in severity with absolute altitude, time at altitude, and rate of ascent
Critical stage
20,000 ft and above
severe effects: loss of consciousness, convulsions, and death
What is hyperventilation
Abnormal loss of CO2 from the blood
Causes of hyperventilation
Causes are usually: - emotional; fear, apprehension, excitement - pressure breathing, - hypoxia
Symptoms of Hypoxia
Symptoms are observable by the individual aircrew member. They vary from one person to the next: Air hunger or breathlessness / Apprehension (anxiety) Fatigue / Nausea / Headache / Dizziness / Hot and cold flashes / Euphoria / Belligerence (anger) Blurred vision Tunnel vision / Numbness / Tingling / Denial
Signs of Hypoxia
Signs are observable by the other aircrew members Increased rate and depth of breathing /Cyanosis /Mental confusion / Poor judgment / Loss of muscle coordination Unconsciousness / Slouching
Symptoms of Hyperventilation
similar to those of hypoxia: Tingling sensations /Muscle spasms /Hot and cold sensations / Visual impairment / Dizziness / Unconsciousness
Differentiate between hyperventilation and hypoxia
Altitude: Above 10,000 ft, assume hypoxia: Below 10,000 ft, assume hyperventilation Symptoms: Cyanosis only seen with Hypoxia Muscle Spasms only seen with Hyperventilation
What is the treatment of hyperventilation / hypoxia.
Treatment Above 10,000 feet- assume hypoxia and treat accordingly. 100% O2 / Descend to a safe altitude. Below 10,000 feet- assume hyperventilation and treat accordingly. Voluntary reduction in rate and depth of respiration is necessary to accomplish this task./ Reading or repeating a checklist in most cases can treat hyperventilation.
Your co-pilot has pain in one tooth, what is it and what do you do?
Land and seek dental care. it is Barodontalgia (trapped gas disorders of the teeth).
What is the treatment for sinus trapped gas dysbarism?
Stop descent of aircraft and attempt to clear by valsalva
A mixture of gases that surrounds the Earth’s surface is the __________.
atmosphere
The ___________ is the domain of weather, winds, turbulence and convection.
troposphere
The physiological zones of the atmosphere are __________, _________ and __________ zones.
efficient, deficient, space equivalent
Oxygen makes up ________ % of gas in the atmosphere.
21
_________ is the fluid part of the blood composed mainly of salt, water and proteins.
Plasma
________ transport approximately _______ % of all O2 in the body.
Red blood cells, 98,5
_________ is a process by which a living organism exchanges gases with its environment.
respiration
Respiration is an __________ process that occurs in two phases, the __________ phase and the _________ phase.
involuntary
inhalation/active
exhalation/passive
What is the mnemonic for the stages of hypoxia?
ICDC
________ hypoxia results when there is interference with the use of O2 by body tissue.
Histotoxic
True of false: Hypoxia can occur at any altitude.
True!
__________ is an excessive rate and depth of respiration leading to abnormal loss of O2.
Hyperventilation
The __________ stage of hypoxia is associated with altitudes of 10,000 - 15,000 feet.
compensatory
