1. Physiology of Flight Objective: Understand the physiology of flight.

2. Physiology of Flight: Overview Principles and Problems of Vision Spatial Disorientation and Motion Sickness Noise and Vibration Heat and Cold During Flight Noxious Gases and Vapors Self-Imposed Stresses

3. Boyle’s Law 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

4. 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.

5. Respiration and Circulation Less Oxygen available for the respiratory system to capture – result? Hyperventilation Hypoxia Circulatory System The Bends The Chokes

6. Rapid Decompression Rapid decompression at a high altitude brings on an explosion as the pressure suddenly decreases. AltitudeTUC 45,000 feet MSL9 to 15 seconds 40,000 feet MSL15 to 20 seconds 35,000 feet MSL30 to 60 seconds 30,000 feet MSL1 to 2 minutes 28,000 feet MSL2.5 to 3 minutes 25,000 feet MSL3 to 5 minutes 22,000 feet MSL5 to 10 minutes 20,000 feet MSL30 minutes or more

7. Principles of Vision

8. Blind Spot: Where the optic nerve connects to the Retina. Rods are responsible for vision at low light levels. They do not mediate color vision, and have a low spatial acuity. Smaller number of rods in the Fovea Cones are active at higher light levels are capable of color vision and are responsible for high spatial acuity

9. We are all a little blind. That’s right, you may pass eye tests without a blink, have 20/20 vision, even see in the dark, but you could still miss seeing a jumbo jet at a mile and a half if the conditions are right. There is a blind spot in your eye about 30 degrees right of center when you are looking straight ahead. Your peripheral vision from the eye compensates for this “defect” because your brain normally combines the pictures from both eyes Hold the picture below at arm’s length and focus both eyes on the cross that is located on the left windscreen. Now, move the picture toward your face. You should be able to see the airplane (located in the right windscreen) all the way in. Okay? Try it again with your left eye closed. The airplane will disappear and then reappear as you draw the picture closer. Ask yourself, “How much airspace will an aircraft cover during the time the other airplane disappeared?”

10. Principles of Vision Blind Spot: Where the optic nerve connects to the Retina. Rods are responsible for vision at low light levels. They do not mediate color vision, and have a low spatial acuity. Smaller number of rods in the Fovea Cones are active at higher light levels are capable of color vision and are responsible for high spatial acuity

11. Principles of Night Vision

13. Spatial Disorientation and Motion Sickness Spatial disorientation - the inability to accurately orient yourself with respect to the Earth’s horizon. We use three sensory systems to maintain our orientation and equilibrium (balance).

14. 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.

15. Spatial Disorientation and Motion Sickness The Vestibular System Semicircular Canals

16. 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.

17. 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.

18. 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 400 o F as a result of aerodynamic heating.

19. 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.

20. 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.

21. Physiology of Flight Objective: Know the physiology of flight.