Physiology of Flight

Physiology of Flight

Physiology of Flight Physiology of flight: how the human body functions during flight

Overview 1. Physiological Divisions of the Atmosphere 2. Hypoxia and Hyperventilation 3. Trapped Gases 4. Decompression Sickness 5. Principles and Problems of Vision 6. Spatial Disorientation and Motion Sickness 7. G-Forces 8. Other Stresses of Flight

Physiological Divisions of the Atmosphere

Physiological Zone Sea Level to 10,000 feet Region of the atmosphere in which there is enough oxygen to allow a normal, healthy person to fly without using special protective equipment

Physiological Zone Sea Level to 10,000 feet May experience some dizziness or discomfort in the ears or sinuses A person can survive above 10,000 without an oxygen mask

Physiological-deficient Zone 10,000 to 50,000 feet This zone has reduced atmospheric and oxygen pressure, so the body must be supplied with supplemental oxygen and supplied under pressure at higher levels in this zone

Physiological-deficient Zone 10,000 to 50,000 feet Most military aircraft and commercial aircraft flying long distances go into this zone with protective equipment

Partial Space Equivalent Zone 50,000 feet to 120 miles above The atmospheric pressure is so low in this zone that a man would lose consciousness even if supplied with 100% oxygen under pressure Earth

Partial Space Equivalent Zone 50,000 feet to 120 miles above Earth When flying in this zone, pilots must have a completely sealed space cabin with its own internally supplied oxygen and capability to remove carbon dioxide and to purify the air

REVIEW 1. The physiology of flight is how the _ functions during flight: a. aircraft b. mind c. body

REVIEW 2. Which zone allows a normal, healthy person to fly without using special protective equipment: a. partial space equivalent b. physiological-deficient c. physiological

REVIEW 3. Most military and commercial aircraft flying long distances fly in this zone: a. partial space equivalent b. physiological-deficient c. physiological

REVIEW 4. When flying in the higher levels of this zone, the body must be supplied with supplemental oxygen under pressure: a. partial space equivalent b. physiological-deficient c. physiological

REVIEW 5. When flying in this zone, pilots must have a completely sealed space cabin with its own internally supplied oxygen: a. partial space equivalent b. physiological-deficient c. physiological

Effects of Reduced Pressure at Altitude As the body goes to high altitudes it must make adjustments to the reduced atmospheric pressure in order to keep the flow of oxygen through the body cells and tissue constant. If the pressure outside the body is greatly reduced and the body is not adequately protected, it cannot make the necessary adjustments.

Hypoxia Hypoxia - a state of too little oxygen in the body cells or tissue. In flight it is usually caused by an insufficient amount of oxygen in the inhaled air. It impairs how the brain and other organs function May be aggravated by other conditions such as anemia, poor circulation of the blood, or the presences of poison or alcohol in the body

Hypoxia Greatest danger when pilot becomes engrossed in duties and doesn t notice the first symptoms. First symptoms may include increased breathing rate, dimming of vision, headache, dizziness, poor coordination and impairment of judgment, and finally the loss of vision and changes in behavior Also includes tunnel vision: a condition in which the edges if your sight gray out to a point where you only have a narrow field of vision straight ahead

Hyperventilation Hyperventilation A person affected by hypoxia tends to increase breathing rate in an attempt to take in more oxygen. It is an abnormal increase in the volume of air breathed in and out of the lungs May continue to gasp until hyperventilation occurs May result from great emotional tension or anxiety.

Hyperventilation Hyperventilation is simply over breathing Symptoms are similar to hypoxia Symptoms include dizziness, hot and cold sensations, nausea, and finally unconsciousness After the person loses consciousness, he no longer gasps for air the conditions corrects

REVIEW 6. Over breathing: a. hypoxia b. hyperventilation c. trapped gases

REVIEW 7. A deficiency of oxygen in the body cells or tissue: a. hypoxia b. hyperventilation c. trapped gases

REVIEW 8. Which condition can lead to the other condition: a. hypoxia leads to hyperventilation b. hyperventilation leads to hypoxia c. either condition can cause the other condition

Trapped Gases As the body ascends and descends during flight, the free gases inside the body cavities expand or contract. Trouble develops when these gases cannot escape, or air from the outside cannot enter

Trapped Gases Gases are most likely to be trapped in the ears, sinuses, teeth, stomach, and intestines Trapped gases cause pressure to build up and the result may be pain and sickness

Ear Block Pressure develops in the middle ear when descent is made too quickly or when one is unable to equalize the pressure because the Eustachian tube is swollen The Eustachian tube allows air to pass outward with ease, but resist passage of air in the opposite direction. During ear block, the process is not working

Ear Block Air can usually be pushed through the Eustachian tube during descent by swallowing, yawning, or tensing the muscles of the throat at intervals, thus causing the pressure within the middle ear to equalize with that of the outside pressure

Sinus Block If an ascent or descent is made too quickly, or if the openings to the sinuses are blocked because the mucous membrane is swollen, pressure builds up within the sinuses and causes pain

Tooth Pain Gases may be trapped in the teeth at altitude in abscesses, imperfect fillings, and inadequately filled root canals The toothache often disappears at the same altitude that if was first observed on ascent.

Stomach and Intestines In flights above 25,000 feet the expanding gases in the stomach and intestines may cause severe pain, lowering blood pressure and eventually lead to shock. Usually results from air that has been swallowed. When pressure falls the partial pressures of the gases in the body fluids decrease. The escaping gases cause decompression sickness.

Decompression Sickness Decompression sickness: a condition resulting from exposure to low pressure that causes dissolved gases in the body to form bubbles Cause might be flying in unpressurized aircraft to high altitude or in aircraft that suddenly experiences decompression the loss of cabin pressure due to a malfunction or accident

The Bends The Bends Release of nitrogen into the joints of the body. Usually the joints of the knee and shoulder

The Chokes Another form of decompression sickness. * At first the pressure is felt as a deep burning sensation, but gradually it becomes a severe stabbing pain, aggravated by deep breathing Deep, sharp pains under the sternum. Increased expansion of the lungs causes the pain to increase. Choking is caused by evolved gas bubbles blocking blood vessels in the lungs

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.

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. Faintness, dizziness, and nausea may result Person could go into shock or become unconscious

Effects of Reduced Pressure at Altitude Begin an emergency descent and land as soon as possible If decompression sickness symptoms still exist after landing, compression therapy will be administered at the nearest hyperbaric facility. The Air Force uses special chambers to train pilots to recognize symptoms of decompression sickness

REVIEW 9. When gases inside body cavities cannot escape: a. hypoxia b. hyperventilation c. trapped gases

REVIEW 10. This procedure can help get rid of by swallowing, yawing, or tensing the muscles of the throat at intervals: a. ear block b. sinus block c. tooth pain

REVIEW 11. When the mucous membrane swells up, causing a build up of pressure and pain: a. ear block b. sinus block c. tooth pain

REVIEW 12. This condition disappears during descent, at the same altitude it was first noticed during ascent: a. ear block b. sinus block c. tooth pain

REVIEW 13. Small bubbles of nitrogen producing itching, hot & cold feelings, and tingling: a. the bends b. the chokes c. stomach & intestines d. the skin

REVIEW 14. Release of nitrogen in the joints, usually the knee and shoulder, causing intense pain: a. the bends b. the chokes c. stomach & intestines d. the skin

REVIEW 15. Expanding gases in flights above 25,000 feet, lowering the blood pressure, affects: a. the bends b. the chokes c. the stomach & intestines d. the skin

REVIEW 16. A severe stabbing pain aggravated by deep breathing: a. the bends b. the chokes c. stomach & intestines d. the skin

REVIEW 17. When decompression sickness becomes more severe, what should pilots should do immediately: a. alert the base b. apply 100% oxygen c. go into shock

REVIEW 18. If decompression sickness continues after landing, what treatment might be administered a. antibiotic treatment at a hospital b. compression therapy in hyperbaric chamber c. extended crew rest in pilot s quarters

Vision Aircrew members must be able to see well to judge speed and distances. Otherwise, they could not take off and land safely In addition, they must be able to distinguish colors to interpret signal flares and beacons They must also have good night vision to fly safely in the darkness

Night Vision What happens when you go inside a dark theater after coming in from the bright sun? Can you see inside at first? How long does it take you to adapt?

Night Vision Pilots experience a similar scenario trying to fly at night They use special goggles with red lenses to help keep the eyes ready to adjust to the dark They also fly by instruments, versus trying to see land marks

Factors Affecting Visions Glare: windshield and windows protect Oxygen deprivation: reduces visual acuity Illumination: cockpits have white lights to reduce shadows and glare Illusions: staring at objects too long can cause. Pilots scan objects to prevent

REVIEW 19. Aircrew members must be able to see well to judge: a.time and speed b. dates and distance c. speed and distances

REVIEW 20. Aircrew members must be able to distinguish colors to interpret: a. signal flares and traffic lights b. airports and beacons c. signal flares and beacons

REVIEW 21. Aircrew members use special goggles with what color lenses to keep the eyes ready to adjust to the dark? a. white b.red c. yellow

REVIEW 22. Airplane cockpits are illuminated with what color lights to help reduce shadows and glare? a. white b.red c. yellow

Spatial Disorientation Spatial disorientation: the lack of knowing an aircraft s position, attitude, and movement It is the inability to accurately orient yourself with respect to the Earth s horizon.

Motion Sickness Motion sickness: a product of the brain receiving conflicting messages about the body s true position A disagreement with what the body feels and what the eyes see If your body has ever been spun rapidly in a circle and then suddenly stopped, if you watch and/or feel the motion of waves while on a body of water, or even if your car is sitting still and you look at objects moving past your car and get the sensation of moving, you may have experienced motion sickness

Spatial Disorientation & Motion Sickness The body uses three systems that work together to figure out position, attitude, and movement: Visual system: eyes sense position based on what they see Vestibular system: inner ear organs sense position by the way the body is balanced Somatosensory system: nerves in the skin, muscles, and joints along with hearing sense position based on gravity, feeling, and sound The brain pieces all of this info together, and when the three systems agree, the brain can accurately determine position, attitude, and movement

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. Use of flight instruments is a sure way to help confirm the position of the horizon

Spatial Disorientation and Motion Sickness Brought about because the balance mechanisms in the inner ear have been affected by inertia (resistance to change in motion). As a result, the hair filaments do not sense the movement of the fluid in the semicircular canals in the normal way motion is not registered

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.

Spatial Disorientation and Motion Sickness The Air Force uses special equipment to help determine a pilot s threshold of tolerance for spatial disorientation and motion sickness

REVIEW 23. Lack of knowing the aircraft s true position, attitude, or movement a. spatial disorientation b. motion sickness c. balance impropriety

REVIEW 24. Inability to accurately orient oneself with respect to the Earth s horizon a. spatial disorientation b. motion sickness c. balance impropriety

REVIEW 25. A product of the brain receiving conflicting messages about the body s true position a. spatial disorientation b. motion sickness c. balance impropriety

REVIEW 26. Nerves in the skin, muscles, and joints along with hearing sense position based on gravity, feeling, and sound a. visual system b. vestibular system c. somatosensory system

REVIEW 27. Inner ear organs sense position by the way the body is balanced a. visual system b. vestibular system c. somatosensory system

REVIEW 28. Eyes sense position based on what they see a. visual system b. vestibular system c. somatosensory system

Acceleration and Deceleration: Increased G-Forces G-force: a measure of gravity s accelerative force A change in an aircraft s speed or motion (dives, turns for example) can induce G-forces Steep turns and dives can generate a force of acceleration that is many times the force of gravity

Acceleration and Deceleration: Increased G-Forces Linear acceleration: a change in speed in a straight line = takeoff, landing, and straight flight Radial acceleration: a change in direction = sharp turns, dives, pulling out of a dive Angular acceleration: simultaneous change in both speed and direction = spins and climbing turns

G-Forces The three types of accelerations induces three types of G- forces on the body Gx: acts on the body from the chest to the back; -Gx occurs during takeoff when A/C gain speed, pushes pilot back into the seat +Gx: the force from the back to the chest during landings, pushes the pilot forward in the shoulder strap Gy: a lateral force that acts from shoulder to shoulder; encountered during aileron rolls on the longitudinal axis Gz: a force that acts on the body s vertical axis = head to foot and foot to head - Gz is applied from head to foot, as when pulling out of a dive +Gz is applied from foot to head, as when in a dive

Positive G-Force Blood rushes from the head toward the feet, just as the normal gravity force does when a person is in a standing position on the ground. In flight, a positive G-Force is experienced when the aircraft is entering a high speed turn or pulling out of a steep dive The cardiovascular system has to react quickly to keep blood flowing to the brain

Negative G-Force The blood rushes from the feet to the head, or as gravity would act upon a person standing on his head. In flight, negative G-Forces are rare, but would occur when an aircraft is diving at a high rate of speed When a pilot goes into a dive, blood can t flow back down through the veins into the heart, yet the arteries are carrying more blood than ever to the head

G-Force +G-force warning signs: progressive loss of vision, onset of tunnel vision, gun barrel vision, gray out, then black out of all vision; if the accelerating G-forces continue, the pilot may finally pass out -G-force warning signs: red out (pilots see a field of red), loss of consciousness

G-Force The Air Force provides pilots a G-suit to help equalize the effects of increased G-Forces G-suit: a piece of clothing that protects pilots from the effects of G-forces The G-suit prevents blackouts by applying pressure to the legs and abdomen to keep blood pressure up and blood circulating to the brain

REVIEW 29. G-force is a measure of gravity s force: a. stall b. accelerative c. decelerated

REVIEW 30. A change in an aircraft s or can induce G-forces a. stalls and acceleration b. speed and motion c. longitudinal and vertical dips

REVIEW 31. Simultaneous change in both speed and direction: a. linear acceleration b. radial acceleration c. angular acceleration

REVIEW 32. A change in direction: a. linear acceleration b. radial acceleration c. angular acceleration

REVIEW 33. A change in speed while traveling in a straight line: a. linear acceleration b. radial acceleration c. angular acceleration

REVIEW 34. Occurs when an aircraft is entering a high speed turn or pulling out of a steep dive, the blood rushes from the head to the feet: a. normal G-force b. negative G-force c. positive G-force

REVIEW 35. Under normal conditions, a force is exerted upon the body and acting in a direction toward the center of Earth: a. normal G-force b. Negative G-force c. Positive G-force

REVIEW 36. When an aircraft is diving at a high rate of speed, the blood rushed from the feet to the head: a. normal G-force b. Negative G-force c. Positive G-force

Other Stresses of Flight Alcohol One drink at 10,000 feet can have the same effect as two or three drinks at sea level. Can affect coordination, limit vision, impact memory, reduce reasoning power, slow reflexes, and lower attention span

Other Stresses of Flight Tobacco It raises the concentration of carbon monoxide in blood Results include reduced ability to see clearly and adapt eyes to the dark

Self-Imposed Stresses Drugs Aspirin, nasal decongestants, tranquilizers or sedatives. Side effects such as drowsiness, loss of balance, and nausea can occur faster

REVIEW 37. Use of this product can affect coordination, limit vision, impact memory, reduce reasoning power, and slow reflexes a. alcohol b. tobacco c. drugs

REVIEW 38. This product raises the concentration of carbon monoxide in the blood, resulting in reduced ability to see clearly and adapt eyes to the dark a. alcohol b. tobacco c. drugs

REVIEW 39. This product raises the concentration of carbon monoxide in the blood, resulting in reduced ability to see clearly and adapt eyes to the dark a. alcohol b. tobacco c. drugs

REVIEW 40. Side effects of this product if used when flying includes drowsiness, loss of balance, and nausea a. alcohol b. tobacco c. drugs

Summary 1. Physiological Divisions of the Atmosphere 2. Effects of Reduced Pressure at Altitude 3. Trapped Gases 4. Decompression Sickness 5. Principles and Problems of Vision 6. Spatial Disorientation and Motion Sickness 7. G-Forces 8. Other Stresses of Flight