Physiology Flashcards
The gas law that predicts drops in partial pressure of oxygen (PO2) with increasing altitude is _________ law. According to this law, decrease in PO2 result from__________.
a) Boyle’s law; percentage of oxygen stays the same but barometic pressure falls.
b) Dalton’s law; percentage of oxygen falls but barometric pressure remains the same.
c) Henry’s law; percentage of oxygen stays the same, but barometric pressure falls.
d) Dalton’s law; percentage of oxygen stays the same, but barometric pressure falls.
d) Dalton’s law; percentage of oxygen stays the same, but barometric pressure falls. Dalton’s law states that the total barometric pressure is made up of the sum of the individual partial pressures of the component gases. With increasing altitude, the relative pressure of oxygen remains the same, but the barometric pressure drops, resulting in a lower partial pressure of oxygen.
Barosinusitis occurs during ________ according to Boyle’s Law.
a) Decent only
b) descent or ascent
c) ascent only
d) at a level of alititude
b) Descent or ascent. Barosinusitis occurs during descent due to inability to equalize sinus pressure. Lower pressure in the sinuses disrupts the mucosal lining, resulting in pain. Although rare during ascent, barosinusitis can occur if there is no route for gas to escape due to respiratory infection with swollen mucosa.
If the FEV1 or FVC is than _______ of predicted or the FEV1/FVC ratio is less than _______, the airman’s PFT will require review by the FAA. In general, if any of these values are less than _______, an applicant will usually be unqualified for pilot duties.
If the FEV1 or FVC is less than 70% or predicted, or the FEV1/FVC ratio is less than 70% it will require review by the FAA. If the values are less than 50%, the applicant is unqualified for pilot duties.
At _____ + Gz’s, the apical perfusion of the lung is nearly zero and air trapping at the base is increased. The Gz induced ventilation and perfusion mismatch results in decreased arterial oxygen and progressive hypoxic effects as G loads are sustained.
+ 3 Gz
The _________ contain the sensors responsible for the hypoxic override that stimulates respiration at low oxygen tension. Oxygen does not play a major role in controlling respiratory rate until the PO2 falls below 60 mmHg (aproximately 8,500 feet), where there is an increase in ventilatory rate.
Aortic and carotid bodies.
Hyperventilation may cause symptoms of generalized weakness, paresthesias, and a “feeling of impending doom”. What is the treatment of a pilot who is having hyperventilation?
At altitude, hyperventilation may be secondary to hypoxia, the primary treatment of hyperventilation in a pilot is to administer supplemental oxygen.
An obstructive defect of the lower airway will have a decreased FEV1/FVC ratio. In addition, the Pulmonary Function Test (PFT) flow-volume loop will show:
a) Flattening of the inspiratory phase with no effect on FEV1.
b) Flattening of the inspiratory phase with a reduced FEV1.
c) Minimal or no flattening of the respiratory phase. The area of the loop will look similar to a normal PFT study except the area will be smaller.
d) Flattening of both the inspiratory and expiratory loops with a reduced FEV1.
B) Flattening of the inspiratory phase with a reduced FEV1. The FEV1/FVC ratio will typically be below 75%.
A restrictive defect would cause the area of the loop to look similar to a normal PFT but smaller. The obstructive defects flatten the inspiratory phase.
Which of the following statements correctly identifies how respired gases drive the rate and depth of ventilation?
a) Sustained G forces result in increased ventilatory drive due to small airway collapse and air trapping in basilar lung segments with decreased perfusion of apical areas.
b) blood oxygen concentration (PaO2) does not play a major role in controlling rate and depth of breathing at altitudes above 8,500 feet.
c) Carbon monoxide poisoning and anemia lower the oxygen content of the blood with a compensatory increase in rate and depth of breathing.
d) Carbon dioxide tension is the primary drive for respiratory rate below altitudes of 8,500 feet.
d) Carbon dioxide tension is the primary drive for respiratory rate below altitudes of 8,500 feet.
Above 8,500 feet, decreases in oxygen tension may also cause an increase in respiration.
This type of hypoxia results from reduced oxygen partial pressure in the atmosphere at altitude, oxygen or pressurization systems malfunction or failure, gradual or slow decompression, rapid or explosive decompression, and poor oxygen system discipline. Poor symptom recognition and delayed corrective action can lead to serious consequences, including death.
Hypoxic hypoxia
This type of hypoxia involves impaired cellular respiration through the disruption of oxidative phosphorylation enzymes. Alcohol, narcotic drugs, and cyanide are common causes
Histotoxic hypoxia
This type of hypoxia is caused by a reduction in circulating hemoglobin or reduced oxygen carrying capacity due to gases such as carbon monoxide that bind tightly to hemoglobin. Other causes include cold, alkalosis, or drugs that can shift the oxygen hemoglobin dissociation curve to the left (reduced oxygen delivery for a given PaO2). Other direct causal factors include hemorrhage, anemia, and/or sulpha drugs.
Hypemic Hypoxia
This type of hypoxia represents a diminished ability of the heart to circulate blood due to local arterial constriction, obstruction of arterial flow, or general circulatory failure. Prolonged positive pressure breathing, shock, G-forces, extreme temperatures, and constriction from straps can be contributing factors.
Stagnant hypoxia
The stages of hypoxia can be categorized into four stages corresponding to altitude and level of saturation. At 10,000 feet to 15,000 feet the O2 saturation is approximately 90-98%. At this stage efficiency is impaired and night vision is decreased by 50%. What is this stage called?
Compensatory stage.
CAMI recommends that on any unpressurized flight to or above _______ feet in the day, or above _________ feet at night, supplemental oxygen should be used.
10,000 feet in the day, 5,000 feet at night.
The ______, like the rest of the retina, depends on a continuous supply of oxygen to function and is exquisitely sensitive to the effect of hypoxia, even at relatively low altitudes.
Fovia
An obstructive defect of the lower airway will have a decreased FEV1/FVC ratio. In addition, the Pulmonary Function Test (PFT) flow-volume loop will show:
a) Flattening of the inspiratory phase with no effect on FEV1.
b) Flattening of the inspiratory phase with a reduced FEV1.
c) Minimal or no flattening of the respiratory phase. The area of the loop will look similar to a normal PFT study except the area will be smaller.
d) Flattening of both the inspiratory and expiratory loops with a reduced FEV1.
B) Flattening of the inspiratory phase with a reduced FEV1. The FEV1/FVC ratio will typically be below 75%.
A restrictive defect would cause the area of the loop to look similar to a normal PFT but smaller. The obstructive defects flatten the inspiratory phase.
Which of the following statements correctly identifies how respired gases drive the rate and depth of ventilation?
a) Sustained G forces result in increased ventilatory drive due to small airway collapse and air trapping in basilar lung segments with decreased perfusion of apical areas.
b) blood oxygen concentration (PaO2) does not play a major role in controlling rate and depth of breathing at altitudes above 8,500 feet.
c) Carbon monoxide poisoning and anemia lower the oxygen content of the blood with a compensatory increase in rate and depth of breathing.
d) Carbon dioxide tension is the primary drive for respiratory rate below altitudes of 8,500 feet.
d) Carbon dioxide tension is the primary drive for respiratory rate below altitudes of 8,500 feet.
Above 8,500 feet, decreases in oxygen tension may also cause an increase in respiration.
This type of hypoxia results from reduced oxygen partial pressure in the atmosphere at altitude, oxygen or pressurization systems malfunction or failure, gradual or slow decompression, rapid or explosive decompression, and poor oxygen system discipline. Poor symptom recognition and delayed corrective action can lead to serious consequences, including death.
Hypoxic hypoxia
This type of hypoxia involves impaired cellular respiration through the disruption of oxidative phosphorylation enzymes. Alcohol, narcotic drugs, and cyanide are common causes
Histotoxic hypoxia
This type of hypoxia is caused by a reduction in circulating hemoglobin or reduced oxygen carrying capacity due to gases such as carbon monoxide that bind tightly to hemoglobin. Other causes include cold, alkalosis, or drugs that can shift the oxygen hemoglobin dissociation curve to the left (reduced oxygen delivery for a given PaO2). Other direct causal factors include hemorrhage, anemia, and/or sulpha drugs.
Hypemic Hypoxia
This type of hypoxia represents a diminished ability of the heart to circulate blood due to local arterial constriction, obstruction of arterial flow, or general circulatory failure. Prolonged positive pressure breathing, shock, G-forces, extreme temperatures, and constriction from straps can be contributing factors.
Stagnant hypoxia
The stages of hypoxia can be categorized into four stages corresponding to altitude and level of saturation. At 10,000 feet to 15,000 feet the O2 saturation is approximately 90-98%. At this stage efficiency is impaired and night vision is decreased by 50%. What is this stage called?
Compensatory stage.
CAMI recommends that on any unpressurized flight to or above _______ feet in the day, or above _________ feet at night, supplemental oxygen should be used.
10,000 feet in the day, 5,000 feet at night.
The ______, like the rest of the retina, depends on a continuous supply of oxygen to function and is exquisitely sensitive to the effect of hypoxia, even at relatively low altitudes.
Fovia
_____________ describes useful flying performance and is affected by physical factors such as rate of decompression, exercise/physical activity, and partial pressure of oxygen related to altitude.
Effective Performance Time (EPT)
An individual with mild COPD can have inadequate cardiopulmonary response at altitude. An important but under recognized cause of COPD is:
a) tobacco use
b) alpha-1-antitrypsin deficiency
c) carbon monoxide poisoning
d) pulmonary fibrosis due to occupational exposure
b) Alpha-1-antitrypsin deficiency.
Hyperventilation causes an alteration of consciousness. This is due to:
a) Displacement of carbon dioxide by oxygen when the flier goes on 100% oxygen under pressure
b) cerebral vasoconstriction, and alkalotic diminution of oxygen release from blood into tissues
c) thoracic hemodynamic changes due to increased minute ventilation
d) distraction of the flier due to anxiety about the symptoms
B) cerebral vasoconstriction, and alkalotic diminution of oxygen release from blood into tissues.
Symptoms of _______ typically start a few hours after arrival at altitudes as low as 6,500 feet but are frequently first noticed the next morning. The major symptom is headache. Other symptoms include fever, nausea, vomiting, dizziness, apathy , general malaise, pallor, and periorbital edema.
Acute Mountain Sicness
Optimal treatment for AMS includes immediate descent to lower altitude and 100% oxygen. If descent is not possible, symptoms may be improved with a portable hyperbaric chamber such as a Gamow bag. As a standard drug treatment, ________ can help relieve symptoms and dexamethasone must be reserved for severe AMS.
Acetazolamide
__________ symptoms start one to two days after arrival to the new altitude above 8,000 feet. It is recognized by shortness of breath and rales accompanied by coughing. Signs include tachycardia, tachypnea, and central cyanosis. Treatment includes immediate descent, and when not feasible or delayed, oral nifedipine can be used.
High Altitude Pulmonary Edema
_________ refers to pain in joints or limbs caused by nitrogen bubble formation in synoval spaces, tendon sheaths, or fascial planes. Itching, tingling, or hyperesthesia characterize the “creeps, niggles”. Mottling or marbling of the skin is not unusual.
Type I Decompression Sickness
________ includes central nervous system, pulmonary, and cardiovascular manifestations. Symptoms of the chokes include substernal chest pain, nonproductive cough, and dyspnea. Neurologic manifestations include spinal paralysis, paraesthesias, and convulsions.
Type II Decompression Sickness
Factors that may predispose someone to decompression sickness are:
a) Increasing age
b) exercise in flight
c) alcohol consumption
d) obesity
e) females are slightly more at risk than men.
F) All the above
f) All the above
Consider the following scenario: You partipate in scuba diving and you drive to your home city, crossing mountains that have an elevation of 10,000 feet. After six hours of driving, you reach your home city (elevation 3,000 feet). You start to feel chest pain and shortness of breath. Which disease are you probably suffering? A) AMS B) HACE C) HAPE D) DCS
D) DCS
When flying after diving, what is the FAA recommendation for prevention of DCS?
Wait 24 hours
In the absence of diving or exercise, DCS is usually prevented by all fo the following except:
a) an unpressurized cabin flying at less than 18,000 feet
b) gradual ascent to altitude
c) pressurized cabin flying at less than 8000 feet
d) prebreathing 100% oxygen prior to flight
b) gradual ascent to altitude. Gradual ascent to altitude is a preventive measure for AMS, HACE, and HAPE…not DCS.
The coriolis illusion results from sudden, simultaneous stimulation of multiple semicircular canals. The flier has been in a steady turn (motion in the yaw plane) long enough for the endolymphatic system to cease its intertial torque upon the hair cells. Then the pilot makes a rapid head motion, such as looking at an instrument or to pick up a dropped pencil. This moves the previously involved (and now unstimulated) semicircular canals into that plane. Their endolymph is put into motion, causing a sensation of roll. The most common coriolis illusion results in a condition known as the ________.
The Leans.
Experience pilots can encounter spatial disorientation, yet non instrument rated pilots are most at risk. True or False.
True
In the _____________, typically the pilot begins a prolonged turn with a moderate bank. After the vestibular sense fatigues, the cupula-endolymph system within the semicircular canals stabilizes to a constant angular velocity and a continuing constant turn is perceived as no motion.
Graveyard spiral
In the __________, the pilot begins a steady turn, long enough for the endolymphatic system to cease its torque upon the hair cells and then makes a rapid head motion. This moves the semicircular canals into that plane and a sensation of a roll occurs.
The Coriolis Illusion
True or False. The potentially hazardous consequences of experiencing vestibular illusions during flight can be prevented by attentive instrument flying for true orientation in space.
True
Accident research conducted between 1987-1996 showed one fatal spatial disorientation accident every eleven days. Over ______ percent of all accidents during this time in which spatial disorientation was a factor resulted in fatalities.
90%
The most important sense for orientation is:
a) Proprioceptive (sensors)
b) Vision (eyes)
c) Vestibular - Semicircular canals
d) Vestibular- Otoliths
B. Vision.
Vision references outside the cockpit provide the most reliable orientation. When outside references are lost, orientation relies on visual reference with the instrument panel control and performance instruments.
The coriolis and somatogyral illusions have which item in common?
a) They involve the inability of the semicircular canal system to register a prolonged, sustained angular velocity accurately.
b) They occur most commonly in pilots who are flying while taking over the counter medications for respiratory infections which may cause vestibular effects.
c) They most frequently involve pilots who do not have instrument ratings, yet are flying in instrument meteorological conditions (IMC).
d) They occur primarily during night flights where visual references are lost or obscured.
c) They most frequently involve pilots who do not have instrument ratings, yet are flying in instrument meteorological conditions.
The normal eye is a +60 D refractive system, with ______ supplied by the cornea and ________ by the unaccomodated lens.
+45 D by the cornea, +15 D by the unaccomodated lens.
Decreases in oxygen levels at altitudes as low as _________ feet at night and __________ feet during the day can affect vision rapidly and before the other special senses.
5,000 feet at night, 10,000 feet during the day.
Stereoacuity is the smallest detectable depth difference that can be seen in binocular vision and is relevant within _______feet of viewing distance.
600
The most common form of color vision deficiency is 6-8% of males with ____ or ______ color deficiencies.
Green or Red
The ____________ and __________are two acceptable measures of pilot color vision.
The pseudoisochromatic test and the Farnsworth Lantern Test.
Which of the following conditions are true about color vision in the flight environment?
A) Because of the safety critical nature of color vision those who are not able to meet the color vision standards defined in the AME Guide are prohibited from obtaining medical certificates.
B) All color vision deficiencies result, at a minimum, in a limitation of the certificate.
C) An applicant can be tested with a number of different color vision tests including the pseudoisochromatic and Farnsworth Lantern Test.
D) Colored flight displays are the only critical area where color vision deficient pilots may have difficulties discriminating colors.
C) There are multiple color vision tests including the pseudoisochromatic plates and Farnsworth Lantern Test.
When comparing photophic, mesopic, and scotopic vision which of the following true?
A) Mesopic and scotopic vision causes the eye to experience a shift, called the Purkinje shift that results in improved color perception and sensitivity toward the end of the spectrum.
B) Scotopic vision occurs during twilight conditions and is strictly reliant on rods.
C) Mesopic vision is found in twilight lighting conditions and relies on variable combinations of rod and cone vision.
D) Scotopic vision provides excellent color vision perception because of the sensitivity of the rods to varying wavelengths of light.
C) Mesopic vision can be characterized as a translational state between cone and rod, or photopic and scotopic vision.
During an examination for a Third Class medical, a 45 year old private pilot with low flying hours presented to his AME with a visual anomaly he attributed to his first prescription for corrective lenses. The pilot described flying over sparsely populated terrain at night. He thought that a light was in motion and prepared to adjust his flight path for proper clearance. The light was actually from a house in the distance. What is the most likely diagnosis?
A single stationary spot of light or object against a black featureless background can appear to be moving into the path of the aircraft. It is believed that this is caused by the brain interpreting saccades as movement of the object in the absence of other visual cues.
The gas law that predicts drops in partial pressure of oxygen (PO2) with increasing altitude is ________ law. Accord to the law, decreases in PO2 result from:
A) Boyle’s law; percentage of oxygen stays the same, but barometric pressure falls.
B) Dalton’s law; percentage of oxygen falls, but barometric pressure remains the same.
C) Henry’s law; percentage of oxygen stays the same, but barometric pressure falls.
D) Dalton’s law; percentage of oxygen stays the same, but barometric pressure falls.
D) Dalton’s law.
Barosinusitis occurs during \_\_\_\_\_\_\_\_\_ according to Boyle's law. A) Decent only B) Descent or ascent C) Ascent only D) At a level altitude
B) Descent or ascent
An obstructive defect of the lower airway will have a decreased FEV1/FVC ratio. In addition, the Pulmonary Function Test (PFT) flow-volume loop will show:
A) Flattening of the inspiratory phase with no effect on FEV1.
B) Flattening of the inspiratory phase with a reduced FEV1.
C) Minimal or no flattening of the inspiratory phase. The area of the loop will look similar to a normal PFT study except the area will be smaller.
D) Flattening of both the inspiratory and expiratory loops with a reduced FEV1.
B) Flattening of the inspiratory phase with a reduced FEV1.
Which of the following statements correctly identifies how respired gases drive rate and depth of ventilation?
A) Sustained G forces result in increased ventilation drive due to small airway collapse and air trapping in basilar lung segments with decreased perfusion of apical areas.
B) Blood oxygen concentration (PaO2) does not play a major role in controlling rate and depth of breathing at altitudes above 8,500 ft (PaO2 less than 60%).
C) Carbon Monoxide poisoning and anemia lower the oxygen content of the blood with a compensatory increase in rate and depth of breathing.
D) Carbon Dioxide tension is the primary drive for respiratory rate below altitudes of 8,500 feet.
D) Carbon Dioxide tension is the primary driver for respiratory rate below altitudes of 8,500 feet.
Which of the following etiologies is descriptive for hypoxic hypoxia?
A) Low oxygen tension of inspired gas due to altitude.
B) Impaired oxidative phosphorylation
C) Carbon monoxide displacement of oxygen from hemoglobin
D) decreased oxygen due to circulatory failure
A) Low oxygen tension of inspired gas due to altitude
In the absence of supplemental oxygen at altitude, compensatory hyperventilation will cause respiratory ___________ and shift the oxyhemoglobin dissociation curve to the __________.
Alkalosis, left.
In the oxygenation of hemoglobin, which of the following is responsible for the combination with oxygen?
a) The ferric iron in hemoglobin
b) The oxidized iron in hemoglobin
c) The carbamino hemoglobin
d) The methemoglobin
e) The ferrous iron in hemoglobin
E. The ferros iron in hemoglobin
The usual effective performance time (a.k.a. Time of Useful Consciousness) when breathing air at altitudes of 25,000 ft and 35,000 ft respectively are:
1) 25 mins; 90-120 secs
2) 15 mins; 60-90 secs
3) 3-5 mins; 30-60 secs
4) 2-3 mins; 15-30 secs
5) 1-2 mins; 10-15 secs
C. 3-5 mins; 30-60 seconds
What percent of carbon dioxide in venous blood is transported in the form of bicarbonate?
a) 5%
b) 6%
c) 22%
d) 72%
e) 90%
d) 72%
Continuous breathing of pure oxygen for 2-3 days at at altitudes of 10,000 feet to 25,000 feet is most likely to produce clinical signs of oxygen toxicity of the:
a) pulmonary system
b) visual system
c) blood components
d) endocrine system
e) central nervous system
a) pulmonary system
The ventilation-perfusion ratio (Va/Qc) of the lungs is greatest in the:
a) left lung
b) right lung
c) upper lobes
d) lower lobes
c) Upper lobes
Man can generally tolerate an appreciable decrease in the ambient barometric pressure because of the following:
a) increased blood flow to the brain with hyperventilation
b) constant percentage of oxygen in the ambient air
c) shape of the oxygen dissociation curve for hemoglobin
d) shift toward a state of respiratory alkalosis
e) decrease in oxygen consumption and metabolic rate
c) shape of the oxygen dissociation curve for hemoglobin
A very commonly used maneuver to stop hyperventilation is prolonged breath holding in maximum inspiration. Aviators should be educated to:
a) Avoid this maneuver because it can lead to syncope
b) instruct this maneuver to aircraft passengers who hyperventilate
c) Avoid the maneuver because hypoxia may result
d) demonstrate the maneuver at the time of physical examination to ensure proper performance
a) Avoid this maneuver because it can lead to syncope.
The total lung capacity is approximately 6000cc; of this volume, approximately 4500cc may be moved in or out of the lung with maximum inspiration and expiration. The volume of air represents the:
a) maximum breathing capacity
b) tidal volume
c) vital capacity
d) functional residual capacity
c) Vital capacity
Of the following factors, which probably does not influence the shift of oxyhemoglobin curve to the right?
a) hydrogen ion
b) exercise
c) 2,3 DPG
d) decreased CO2
d) Decreased CO2
During the various phases of inspiration and expiration there exists an alveolar pressure that is the result of the combined partial pressures of several gases such as oxygen, carbon dioxide, and nitrogen. Of the several gas laws, which one most appopriately applies to this phenomenon?
a) Henry’s
b) Dalton’s
c) Boyle’s
d) none of the above
B) Dalton’s law
Which of the following is true regarding the 47 mmHg of water vapor pressure exerted with those gases involved in pulmonary physiology?
a) is not affected by temperature
b) it is not affected by altitude
c) The pressure is reduced by one half at 18,000 feet
d) It must be disregarded when calculating the partial pressures of inspired gases.
b) It is not affected by altitude.
Water Vapor Pressure is temp dependent only.
A lipoprotein substance containing dipalmitoyl lecithin, “surfactant”, is secreted by the alveolar epithelium and aids respiration by which of the following actions?
a) By decreasing the surface tension of the fluid lining the alveoli and respiratory passages.
b) By enhancing the expansion of the lungs.
c) By equalizing the diameter of the alveoli
d) All the above.
d) All the above
Of the several initial cardio-pulmonary responses to acute hypoxia that occur with exposure to altitude, which of the following should NOT be included?
a) hyperpnea
b) pulmonary hypertension
c) tissue acidosis
d) tachycardia
c) tissue acidosis. Initially there is a hyperventilation which lowers CO2 and makes the person alkalotic.
The aortic and carotid bodies are peripheral chemo-receptors located in the wall of the aorta and wall of the carotid arteries, respectively. The rather integrated response that occurs when these structures are stimulated increases cardiopulmonary activity producing increased ventilation. What condition(s) would most likely stimulate these chemo-receptors?
a) Decreased O2 (hypoxia)
b) Carbon monoxide poisoning
c) Both a and b
d) Neither a nor b
a) Decreased O2 (hypoxia)
The Hering- Breuer inflation-deflation reflex can be described as a reaction to a stimulus of the stretch receptors of the bronchi and bronchioles during inspiration. This prevents over-inflation. A reaction to the lack of that stimulus to those receptors during expiration initiates the onset of inspiration. The major effects of these reflexes could best be described as a(n):
a) decrease in tidal volume and a compensatory increase in respiratory rate.
b) increase in tidal volume and a compensatory increase in respiratory rate.
c) increase in tidal volume and decrease in respiratory rate.
d) decrease in tidal volume and a compensatory decrease in respiratory rate.
a) decrease in tidal volume and a compensatory increase in respiratory rate.
In regards to respiratory physiology, specifically the function of the diaphragm, what position or G force would one expect to result in less efficient pulmonary function and a resultant fall in functional residual capacity (FRC)?
a) Sitting or standing, +Gz
b) Lateral decubitus, +/- Gy
c) Supine, + Gx
d) None of the above
c) Supine, + Gx. Abdominal contents press on the diaphragm.
At 22,000 feet altitude, acute hypoxic exposure typicall produces all of the following cardiovascular effects EXCEPT:
a) the minute ventilation rate almost doubles
b) a marked increase in respiratory frequency is noted.
c) respiratory tidal volume increases
d) an increase in heart rate of about one-third over that at sea level
e) venous oxygen tension is raised.
b) A marked increase in respiratory frequency is incorrect. There is only a mild increase. So this is a nuanced question.
The increase in pulmonary ventilation produced by exposure to a given altitude above 8000-10,000 feet is due to:
a) the arterial oxygen tension stimulating respiration through aortic and carotid bodies
b) reduced arterial CO2 tension produced by increase in ventilation tending to depress respiration
c) increased arterial CO2 tension and acidosis stimulating the respiratory center
d) resultant of conflicting factors of a and b.
d) resultant of conflicting factors of A and B.
Hyperventilation may be caused by all of the following situations EXCEPT:
a) pilots learning pressure breathing
b) resuction of alveolar oxygen tension to 75 to 80 mmHg.
c) voluntary overbreathing in preparation for a breath hold dive into water.
d) motion sickness
e) ambient temperature and whole body vibration at 4-8 Hz.
b) Reduction of alveolar oxygen tension to 75-80 mmHg is incorrect. The alveolar oxygen tension has to drop to less than 60 mmHg to begin causing hyperventilation.
At what level of carboxyhemoglobin do you observe symptoms?
a) 10%
b) 15%
c) 20%
d) 25%
b) 15%
The portion of the circulation with the largest volume is the:
a) systemic venous system
b) capillary network
c) small veins and venules
d) aorta plus the large arteries
c) Small veins and venules make up the largest portion of the venous capicitance which carries 70% of the blood volume.
Acidosis, elevated pCO2, and elevated temperature of the body all shift the oxyhemoglobin dissociation curve to the right. A shift to the right at a given pO2 means:
a) there will be no change in the tissue oxygenation
b) tissue oxygenation will be less
c) tissue oxygenation will be enhanced
d) hemoglobin saturation will be increased
c) tissue oxygenation will be enhanced.
The carotid and aortic bodies are important in aerospace physiology because they:
a) initiate respiratory and circulatory reflexes in response to acidosis or alkalosis
b) initiate reflex renal loss or retention of bicarbonate in the presence of acidosis or alkalosis
c) initiate immediate circulatory reflexes in response to sudden drop in blood pressure
d) initiate respiratory and circulatory reflexes in response to decreased oxygen tension
e) initiate reflex hyperventilation or hypoventilation in the presence of high or low concentrations of CO2.
d) initiate respiratory and circulatory reflexes in response to decreased oxygen tension
Cyanosis is a notoriously poor early indicator of hypoxia because of all of the following EXCEPT:
a) cyanosis will not become evident until there is more than 5 gm% unsaturated hemoglobin
b) cyanosis may never develop in the presence of methemoglobin or sulfhemoglobin
c) cyanosis is more difficult to see in the dark skinned races
d) the ability to note cyanosis varies greatly among observers
b) cyanosis may never develop in the presence of methemoglobin or sulfhemoglobin is the wrong answer because cyanosis is usually present in these entities even without frank hypoxia.
What is the most true regarding psychomotor and intellectual performance during voluntary hyperventilation?
a) both intellectual and psychomotor performance fall with only moderate hyperventilation (PaCO2 25.0 torr)
b) both intellectual and psychomotor performance fall, but only with more severe fall in PaCO2 (15 torr).
c) Intellectual performance is maintained while psychomotor performance falls at 25.0 torr PaCO2.
d) Intellectual performance is maintained while psychomotor performance falls at PaCO2 of 15.0 torr.
d) Intellectural performance is maintained while psychomotor performance falls at PaCO2 of 15.0 torr.
The effect of hypoxia, which is caused by the exposure to altitude, on the heart is:
a) bradycardia
b) tachycardia
c) no change in heart rate
d) ischemic heart disease
e) sinus arrhythmia
b) Tachycardia
The cardiovascular system responds to hypoxia by a(n):
a) decrease in systemic blood pressure.
b) decrease in cardiac output
c) increase in pulmonary artery blood pressure
d) decrease in heart rate
e) decrease in heart size
c) Increase in pulmonary artery blood pressure.
The time of useful consciousness following a rapid decompression from 8000 feet to 35000 feet while breathing air is about:
a) the same as mask removal at the same altitude
b) the same as a decompression breathing oxygen at 50,000 feet
c) 15 seconds
d) 30 seconds
d) 30 seconds
If the concentration of carbon dioxide in inspired air is maintained constant at 0.03 percent while the inspired concentration of oxygen is gradually lowered from a starting value of 20.93 percent; which of the following oxygen values will approximately double the resting volume of respiration?
a) 18 percent
b) 16 percent
c) 8 percent
d) 4 percent
c) 8 percent oxygen
Avogadro’s Law states that:
a) the numbers of molecules present in equal volumes of gases at the same temperature and pressure are equal.
b) the volume of gas is inversely proportional to the pressure with temperature remaining constant.
c) Each gas in a mixture of gases behaves as if it alone occupied the total volume and exerts a pressure, its partial pressure, independently of the other gases present.
d) time relative rates of diffusion of gases under the same conditions of temperature and pressure are inversely proportional to the square root of the densities of those gases.
a) the numbers of molecules present in equal volumes of gases at the same temperature and pressure are equal.
The barometric pressure at 18,000 feet is approximately 380 mmHg; therefore, the partial pressure of oxygen would be:
a) 159 mmHg
b) 101 mmHg
c) 96 mmHg
d) 80 mmHg
d) 80 mmHg. 380 x .21 (percent of oxygen)= 80
How may rightward or leftward shifts in the oxygen-hemoglobin dissociation curve influence tolerance at altitude?
a) Altitude tolerance, per se, is not affected.
b) Rightward shifts cause intolerance; leftward shifts cause tolerance.
c) Carbon dioxide and 2,3 DPG cause intolerance
d) A leftward shift at altitude enhances tolerance
e) Abnormal hemoglobins having displaced dissociation curves always decrease tolerance.
d) A leftward shift at altitude enhances tolerance.
What is the most likely cause of orthostatic hypotension after space flight?
a) neurogenic reflex
b) hyperactive carotid sinus
c) Increased ADH
d) Baroreceptor impairment
e) Electrolyte imbalance
d) Baroreceptor impairment
If blood pressure is 120/80 at heart level, what would the systolic pressure be at eye level when under +2Gz?
a) 142 mmHg
b) 120 mmHg
c) 98 mmHg
d) 76 mmHg
e) 54 mmHg
D) 76 mmHg
Column of blood from heart to eye level is 22 mmHg.
120 systolic - 22 equals 98 at 1G. 98- 22 = 76 mmHg at 2 G’s.
In a hypoxic environment, reflex mechanisms result in an increased respiratory rate and tidal volume. This compensatory mechanism is primarily due to stimulation of the:
a) pneumotaxic center
b) aortic/carotid bodies
c) Gauer-Henry reflex
d) carotid sinus
e) atrial volume receptors
b) Aortic/Carotid Bodies
In patients with chronic obstructive airway disease:
a) the safety of air transportation is improved if supplementary oxygen is available.
b) respiratory status may decline if 100% oxygen is given.
c) pulmonary function tests provide a useful indication of likely inflight problems
d) flight is contradicted if there is dyspnea at rest
e) all of the above are correct
e) All of the above are correct.
In aircrew who suffer a spontaneous pneumothorax:
a) the treatment of choice is pleurectomy
b) the treatment of choice is chemical pleurodesis
c) the recurrence rate is 30% after a first pneumothorax
d) the condition may manifest only when airborne
e) a, c, and d are correct.
e) A, C, and D are correct.
With regard to asthma, all of the following statements are correct EXCEPT:
a) sudden incapacitation in aircrew with asthma is uncommon.
b) most those with childhood asthma will grow out of the condition by puberty.
c) reasons for permanent disqualification include persistent bronchial hyper-reactivity.
d) the prevalence of asthma in the adult population is about 2.5 - 5%.
e) trained aircrew with well-controlled asthma may continue to be licensed to fly.
b) Most of those with childhood asthma will grow out of the condition by puberty is incorrect. Again, this is a subtle question. 50% of the those diagnosed with childhood asthma grow out of the condition by puberty.
