Aerospace Physiology

UPT Aerospace Physiology Review

What is the composition of the atmosphere?

78% nitrogen, 21% oxygen, and 1% other gases

What is the concern of Human Factors?

Optimizing the relationship between people and their activities

What is the standard temperature lapse rate in Fahrenheit and Celsius?

3.6 F and 2 C per 1000 feet (up to 35000 feet)

What is the Physiological Zone and how far does it extended?

Zone of the atmosphere the human body is adapted to. It extends from Sea Level to 10000 feet

What is the Physiological Deficient Zone and how far does it extend?

Zone of the atmosphere which requires oxygen. It extends from 10000 to 50000 feet

What is the Space Equivalent Zone and how far does it extend?

Zone of the atmosphere which requires a pressure suit. It extends from 50000 feet to infinity.

In what units is the weight of the atmosphere measured?

Pounds per square inch (psi), millimeters of mercury (mmHg), or inches of mercury (inHg)

What is Dalton’s Law of Partial Pressure?

The partial pressure of a single gas in a mixture contributes to the sum of the entire mixture

What is Boyle’s Law?

Volume of gas is inversely proportional to the pressure surrounding it (Balloons)

Do wet or dry gases expand faster?

Wet

What is Henry’s Law?

If pressure is reduced above a solution, gas will release from the solution (Soda Bubbles)

What is the Ideal Gas Law?

Temperature is proportional to pressure and pressure is inversely proportional to volume.

Is the temperature of flight equipment stable in the cockpit?

No

What is Gaseous Diffusion?

Movement of gas from areas of high pressure to low pressure (Breath and Exhale from diaphragm)

What are the phases of Respiration?

Ventilation, Diffusion, Transportation, and Utilization

What is Ventilation?

The inhalation and exhalation of gas to maintain a balance of Oxygen and Carbon Dioxide; Oxygen in, Carbon Dioxide out

What is the normal breathing rate of an adult?

12-16 breaths per minute

What is Diffusion and what process is associated with it?

Oxygen and Carbon Dioxide pass from the alveoli (at the end of the bronchioles) into the blood stream. This is accomplished through Gaseous Diffusion

What is Circulation?

Transportation of Oxygen, Carbon Dioxide, Nutrients, and Waste through the blood stream

What does oxygen bind with to be transported throughout the body?

Hemoglobin

In what cell is hemoglobin located?

Red blood cells

What molecule will hemoglobin bind with over oxygen?

Carbon Monoxide (CO)

What is Hypoxia?

A deficiency of oxygen sufficient to cause impairment of function

What is hypoxia’s most dangerous characteristic?

Insidious onset (sneaky)

What are the kinds of Hypoxia?

Hypoxic, Hypemic, Stagnant, and Histotoxic

What is Hypoxic Hypoxia caused by?

A reduction of partial oxygen in the lungs causing deficient exchange of oxygen by alveoli

What are the common ways Hypoxic Hypoxia is induced?

High altitudes and hyperventilation

What are some signs (Objective) of Hypoxic Hypoxia?

Cyanosis, degraded reaction time, euphoria, belligerence, muscle incoordination, or unconsciousness

What are some symptoms (Subjective) of Hypoxic Hypoxia?

Air hunger, fatigue, headache, or dizziness

What is Time of Useful Consciousness?

Time after losing oxygen until all useful function is lost

What are some factors which affect Time of Useful Consciousness?

Physical Fitness, Stress, Rate of Ascent and Enivronmental Temperature

How does a Rapid Decompression affect Time of Useful Consciousness?

Reduces time available by up to 50%

What is Oxygen Paradox?

Worsening of hypoxia symptoms following gangloading to 100% oxygen

What is Hypemic Hypoxia caused by?

The oxygen carrying capability of hemoglobin being reduced

What are common causes of Hypemic Hypoxia?

Carbon monoxide, blood loss, anemia, and sulfa drugs

What is Stagnant Hypoxia caused by?

Inability for blood to be transported through the body

What are common causes of Stagnant Hypoxia?

G forces, cold temperatures, sitting still, and shock

What does hyperventilation cause in relation to Stagnant Hypoxia

Localized stagnation in the lungs

What is Histotoxic Hypoxia caused by?

Tissues and cells are unable to use oxygen

What are common causes of Histotoxic Hypoxia?

Cyanide, alcohol, smoke, and narcotics

What is Hypocapnia?

The excess loss of carbon dioxide (CO2) from blood

How should Hypocapnia be treated and why?

Exactly like Hypoxic Hypoxia due to similar symptoms

What are the four areas Trapped Gas Disorders can affect?

Ear, Sinus, Gastrointestinal Tract, and Teeth

What phases of flight are the four areas of Trapped Gas Disorders most severe?

Ear: Descent
Sinus: Descent
GI Tract: Climb
Teeth: Climb

What area of Trapped Gas Disorder is associated with pain in multiple teeth?

Sinus

What is the fifth area of Trapped Gas Disorder?

Lungs

What is Decompression Sickness (DCS)?

Nitrogen bubble formation from tissues and fluids of the body

What activity is DCS associated with over Aviation?

Scuba Diving

What are The Bends?

Deep, dull pain in the joints (Musculoskeletal) caused by DCS

What are The Chokes?

Deep, sharp pain under the sternum with a non-producing cough caused by DCS

What are The Creeps?

Skin swelling or bubbling caused by DCS

What are Central Nervous System (CNS) manifestations?

Shock, clammy skin, headaches, visual disturbances, or unconsciousness caused by DCS

Are aircrew members allowed to self-medicate?

Sometimes (Only if pre-approved by flight doctor)

What is the Air Force golden rule regarding alcohol?

12 hours bottle to throttle (to include after-effects)

Is nicotine allowed while flying an aircraft?

Yes, but tobacco is not

Is smoking bad?

Yes

What is Hypoglycemia and how is it avoided?

Low blood sugar; Complex carbs and proteins

What are the 3 types of fatigue?

Acute, Cumulative, and Chronic

What is the positive benefit of Caffeine?

Masking of fatigue

What is the maximum amount of caffeine that can be consumed daily?

600 mg

How much of our daily interactions does Vision cover and is it usually reliable?

80%; yes

What is the difference between Rods and Cones?

Rods cover Black and White, Night vision while Cones cover Color Daytime vision

What is Rhodopsin?

Protein that gives Rods 10000 times more light sensitivity than Cones

What are the three types of vision and what time do they cover?

Photopic: Daytime (Cones)
Scotopic: Nighttime (Rods)
Mesopic: Dawn and Dusk (Rods and Cones)

What is the Physiological Night Blind spot and why does it exist?

Fovea Centralis; Concentration of only Cones for best color vision and visual acuity

What is the Parafovea?

Concentration of Rods that surrounds the Fovea

What is the Periphery primarily composed of?

Rods

What is the Physical Blind Spot and why does it exist?

Optic Disk; lack of photoreceptors (Rods and Cones)

Why is the Physical Blind Spot not typically noticed?

Binocular vision (use of both eyes)

What is the difference between focal and peripheral vision

Focal: Orients a perceived object in space relative to observer; 3 degrees; uses Cones
Peripheral: Used to orient oneself to environment; 150 degrees; uses Rods

What are some examples of Daytime Visual Illusions?

Sloping Cloud Decks, Size of Runway, Weather, and Terrain

What are the two methods of Scanning and when should they be used?

Z pattern: Daytime
Diamond pattern: Night

How much space off the center of the object should you use when using the Diamond Pattern?

5-10 degrees off center

What are some examples of Nighttime Visual Illusions

Blackhole Illusion, Autokinesis, and False Horizon

How should Visual Illusions be overcome?

Trust your instruments

What should aviators do if they encounter lasers?

Look away

What are the 4 systems of Situational Awareness and what do they govern?

Visual: Eyes
Somatosensory: Joints and muscles
Vestibular: Fluid in Inner Ear
Auditory: Hearing

What is the difference between Conscious and Subconscious Processing?

Conscious: Slow and Limited; Accurate and Reliable
Subconscious: Fast and Parallel Processing; Unreliable

Can information move from the Conscious to the Subconscious?

Yes

What are the three levels of Situational Awareness?

Level 1: Perception (Basic)
Level 2: Comprehension (Intermediate)
Level 3: Prediction (Advanced)

What should be done if Situation Awareness is lost?

Aviate, Navigate, Communicate

What are the three types of Spatial Disorientation (Spatial D) and which one is the most dangerous?

Type I: Unrecognized (MOST DANGEROUS)
Type II: Recognized
Type III: Incapacitating

When does Spatial D occur?

When there is a disagreement between the 4 Orientation Sensory Systems

What is usually the most reliable orientation system for flying?

The Visual System

How should the Auditory System be used while flying?

Actively

What are the two components of the Vestibular System and what do they govern?

Semicircular Canals: Roll, Pitch, Yaw (XYZ axis) motions
Otolith Organs: Acceleration and Gravity

Disagreement in the Semicircular Canals and/or Otolith Organs can result in what disorders?

Spatial D and Motion Sickness

What are the minimum degrees of movement for the Semicircular Canals to detect movement and how long does it take for the hairs to settle?

2 degrees per second; 30 seconds

What induces Vertigo?

Diso

Are the Otolith Organs reliable in flight?

No

What are the two Otolith Organ (Somatogravic) Illusions?

Pitch up/down: False sensation of Z axis movement when exposed to linear acceleration
G-Excess Effect: False sensation of Bank Angle when the head is moved in a turn

What are the three Semicircular Canal (Somatogyral) Illusions?

Leans: Hairs settle after 30 seconds, giving the feeling of straight flight (Leads to Graveyard Spiral)
Coriolis: Multiple Semicircular Canals affected leading to tumbling sensation
Nystagmus: Eyes try to catch up to vestibular system leading to disorientation and fatigue

What are some factors which exacerbate Spatial Disorientation?

Weather, Time of Mission, Self-Medication, Dehydration, and Fatigue

What are some ways to prevent Spatial Disorientation?

Trust your instruments, Talk to your Aircrew, and Transfer Aircraft Control

What is the primary way Motion Sickness is induced?

Decoupling of Visual and Vestibular System

What is the most common axis of acceleration for aviators to experience?

Positive Z Axis (pitch) acceleration (+Gz)

Can aviators easily pull and sustain Negative Z Axis acceleration?

No

What are the 5 factors which govern G-tolerance?

Magnitude of Force, Duration of Exposure, Rate of Application, Direction of Force, Previous G Exposure,

Can aviators G-lock in the T-6?

Yes

What are the G thresholds for Positive Gs?

1-3 G: Pooling Begins
3-4 G: Grayout
4-5 G: Blackout
5-6 G: Unconscious