309 Flight Physiology > Exam 1 > Flashcards

Exam 1 Flashcards

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1
Q

At what altitudes does pressure change most rapidly?

A

At LOWER altitudes! (SL to 10,000)

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2
Q

At Sea Level on a standard day, mmHg = ____

A

760

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3
Q

At 18,000’ on a standard day, mmHg = ____

A

380

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4
Q

Above what altitude is supplemental oxygen needed to fully function?

A

10,000’

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5
Q

Define Dalton’s Gas Law and it’s equation

A
  • Each component of a gas contributes to the total pressure.

- Partial Pressure = (total pressure) x (% gas)

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6
Q

What is the partial pressure of Oxygen delivered by life support at the “service ceiling” (minimum) of the equipment?

A

104 (considered the partial oxygen minimum for life support)

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7
Q

What is the formula to determine oxygen partial pressure?

A

Partial Pressure = (total pressure) x (% gas)

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8
Q

What is the service ceiling for an oxygen system that delivers 40% to the human?

A 
104 = (?) x (.40)
260 = ?
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9
Q

What is the partial pressure available to a person breathing 28% oxygen at 26,000’ altitude?

A 
PO2 = (269.8) x (.28)
PO2 = 75.544 mm Hg
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10
Q

What minimal percentage of oxygen should an individual breathe to maintain peak performance at 24,000’ altitude?

A

104 = (294.4) x (?)
.35 = ?
(35%)

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11
Q

What does Boyle’s Law discuss?

A

Gas when it is subjected to PRESSURE

- trapped gas, expansion and compression

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12
Q

What does Charles’ Law discuss?

A

Gas when it is subjected to HEAT

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13
Q

What does Henry’s Law discuss?

A

Gas when it is dissolved in solution (The Bends!)

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14
Q

What does the Law of Gaseous Diffusion tell us?

A

Gases will diffuse from HIGH to LOW pressure naturally

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15
Q

What are the 4 steps for oxygen processing in the human?

A
  1. Ventilation
  2. Diffusion
  3. Transporting
  4. Utilization
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16
Q

Describe the Ventilation step of O2 Processing. What is the best respiratory rate?

A

Air is filtered, warmed, and humidified.

12 - 16 per minute

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17
Q

What are the mechanics of Normal Breathing?

A 
Inhalation = Active Effort
Exhalation = Passive
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18
Q

What are the mechanics of Pressure Breathing?

A 
Inhalation = Passive
Exhalation = Active Effort (purse your lips and blow out long and slow)
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19
Q

Describe the Diffusion step of O2 Processing. What mm Hg will water vapor always equal?

A
  • O2 is diffused across the alveolar wall to the blood!
  • O2 and PRESSURE are inhaled (from the environment) and combined with WATER VAPOR and CO2 from within our body
  • Water Vapor = 47 mm Hg
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20
Q

What is homeostasis?

A
  • The condition compatible with optimum cellular and bodily function
  • Body needs Nutrition, O2, and Rest for optimal homeostasis
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21
Q

What is Hypoxia?

A

O2 deficiency in blood, body tissues and cells that causes impairment (feel normal but brain processes are slowed)

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22
Q

What are the mechanics of Hypoxic Hypoxia? What are the most common causes?

A
  • FLOW of O2 to the LUNGS is interrupted

- Altitude, Drowning

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23
Q

What are the mechanics of Histotoxic Hypoxia? What are the most common causes?

A
  • Normal METABOLIC ACTIVITY (Krebs Cycle) of O2 in the body/brain cells is interrupted
  • Alcohol, Cyanide
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24
Q

What are the mechanics of Hypemic Hypoxia? What are the most common causes?

A
  • Ability of the blood cells to TRANSPORT O2 is interrupted

- Carbon Monoxide Poisoning, Smoke, Anemia

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25
What are the mechanics of Stagnant Hypoxia? What are the most common causes?
- CIRCULATION of blood arriving at CELLS is interrupted | - G's, Shock, Hyperventilation
26
What is Deep Vein Thrombosis? What causes it?
- Venous Flow - When you sit in one place for a long time without contracting your muscles, blood clots can form - When you get up and move, blood clots travel to lungs
27
At what altitude does the temperature stabilize?
~35,500'+ = -55C
28
Define effective performance time. What are the EPTs at FL180, FL250, and FL350?
- The time from exposure to hypoxic conditions until an individual is no longer able to manage safe operations 1. FL180 = 20-30 minutes 2. FL250 = 3-5 minutes 3. FL350 = 30-60 seconds
29
How will a RAPID decompression affect EPTs?
It will decrease EPTs by 30-50%
30
Describe hyperventilation
- An abnormal increase in the rate and depth of breathing - Loss of CO2 exceeds the body's production of CO2, leading to cerebral vasoconstriction and the brain going into a hypoxic state
31
What are some symptoms of hyperventilation?
Gradual onset of: - Muscle spasms - Pale/clammy skin
32
What are some symptoms of hypoxia?
Rapid onset of: - Flaccid muscles - Cyanosis - Difficulty interpreting info - Slow to respond to emergencies
33
SCREAM checklist
``` Supply Connections (5) Regulator Emergency Equipment Adjustment (of mask) Mask (condition) ```
34
Describe the atmosphere. What are its functions? What are the components?
Functions as life support and protection, consists of pressure, water vapor, temperature...primary gases 78% Nitrogen 21% O2
35
Describe some characteristics of Carbon Monoxide
- 200-250 times more attractive to hemoglobin - Half-life of blood CO is 21.5 hours at rest - De-metabolizes in 5.25 hours when treated with 100% O2 - De-metabolizes in 20-30 mins when treated with Hyperbaric Therapy
36
Is it possible to have more than 1 type of hypoxia at once? Give an example.
``` Yes! Ex: Rapid Decompression = Hypoxic Cold Temp. = Stagnant Medications = Histotoxic Smoker = Hypemic ```
37
How would you treat for hypoxia?
- 100% O2 - Breathe at a normal rate and depth - Descend below 10,000'
38
When are Vasoconstrictors used to treat trapped gas?
In emergencies ONLY
39
What would cause a delayed ear block?
Breathing 100% O2 after being in an environment breathing less than 100% (ex: being in the chamber)
40
At what altitude will you encounter 1/2 the Earth's atmosphere?
18,000'
41
What is a Rapid Decompression?
Total loss of cabin pressure in less than .5 seconds (with a 10 psi pressure change)
42
What is Evolved Gas referring to?
Gas forming were it did not exist before
43
Explain how Henry's Law applies to Decompression Sickness?
When the pressure drops, gas becomes supersaturated and bubbles out of solution - this causes expansion and inflammation of the cells
44
What are the mechanics of Decompression Sickness?
- O2 and CO2 get used up, but Nitrogen remains unused and gets absorbed by by the body and saturates the tissues - When pressure DECREASES around us, N becomes supersaturated and will bubble out of its solution, causing tissues inflammation (PAINFUL)
45
How do we asses our risk (R value) for DCS?
Tissue Nitrogen partial pressure (P x N2 - pressure you're at) and the Pressure surrounding the individual (PB - pressure you end up at) R = P x N2/PB
46
What are the 4 types of DCS?
1. Bends 2. Central Nervous System symptoms 3. Skin symptoms 4. Chokes
47
What happens to someone experiencing the Bends?
- N bubbles form in larger joints - Negative Pressure leads to bubble formation - Pain, can be alleviate with a return to pressure (pilots most likely to feel in the elbows/shoulders)
48
What has happened to someone experiencing CNS symptom due to DCS?
- N bubbles are in the brain and/or spinal cord
49
What happens to someone experiencing Skin symptoms due to DCS?
- N bubbles form under the skin
50
What happens to someone experiencing the Chokes?
- N bubbles form in the capillaries of lungs and prevent O2 transfer to blood (Stagnant Hypoxia)
51
At what R value is saturation achieved? When do bubbles develop?
``` R = 1 (saturation - nothing happens) R = 1.5 (bubbles) ```
52
What are Oxygen Regulator Systems used for? What are the 3 different types?
- Used to meter the flow of O2 to the user 1. Continuous Flow 2. Diluter Demand 3. Pressure Demand
53
Describe a Continuous Flow O2 Regulator System
- PASSENGER Delivery System - Used from FL180 to FL250 - Constant flow of 1L/10,000' - Inefficient
54
Describe a Diluter Demand O2 Regulator System
- AIRCREW Delivery System - Used up to FL350 ~operational ceiling~ (FL400 emergencies) - Provides mixture of 100% O2 and Ambient Air UPON DEMAND
55
Describe a Pressure Demand O2 Regulator System
- AIRCREW Delivery System - Used up to FL450 (FL500 emergencies) - Provides mixture of 100% O2, ambient air, AND supplemental pressure as altitude increases above 28,000' - Purpose: to raise partial pressure of O2 at lungs - Problems: Hyperventilation
56
What are the FAA requirements for oxygen use in UNpressurized a/c? (91.211)
- When cabin is between 12,500' and 14,000' for more than 30 minutes - If cabin exceeds 14,000' - PASSENGERS: If cabin exceeds 15,000'
57
What are the FAA requirements for oxygen use in PRESSURIZED a/c? (91.211)
- No Quick Don: With 2 pilots are at the controls, 1 must put on O2 at FL350 - Quick Don: With 2 pilots at the controls, 1 pilot doesn't have to don the mask until FL410. If 1 pilots leaves the controls above FL350 the other must don a mask
58
What are the Connections referred to in the SCREAM checklist?
1. Interfoam 2. Nose 3. Helmet 4. Hose Connection 5. ????
59
Fick's Law of Diffusion (equation)
Volume of a gas ~ (Area of Membrane) x (Diffusion Constant) x (Partial Pressure GRADIENT) / (Thickness of Membrane) Vgas ~ (A)(D)(P1-P2)/T
60
What 2 elements are inhaled from the environment during the Diffusion step of O2 processing?
O2 and PRESSURE
61
What 2 elements are provided from within the body during the Diffusion step of O2 processing?
WATER VAPOR and CO2
62
What % of O2 is required to be fully functioning at Sea Level? What about at 10,000'?
- 21% | - 30%
63
Durning a flight, who is most at risk to get Pyrolysis?
Flight Attendants because they are up and walking during the flight
64
What is the half life of blood carbon monoxide at rest?
21.5 hours at rest
65
How quickly will blood carbon monoxide de-metabolize when treated with 100% O2? What about hyperbaric therapy?
- 5.25 hours | - 20 to 30 mins
66
What is one of the most susceptible senses to O2 deprivation?
EYE SIGHT
309 Flight Physiology
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