Humans at High Altitude (Lecture 18) Flashcards

1
Q

True or False: Atmospheric pressure decreases at high altitudes

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

True or False: As the barometric pressure decreases, the atmospheric oxygen partial pressure increases proportionately

A

False, As the barometric pressure decreases, the atmospheric oxygen partial pressure DECREASES proportionately

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Alveolar PCO2 ______from sea level values of 40 mm Hg to lower values at high altitudes/

A

Decreases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

True or False: The decrease in alveolar PCO2 in acclimated people is greater compared to unacclimilized individuals due to increased respiration

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

True or False: Acclimatized people can increase their ventilation

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

True or False: As altitude increases, the air that reaches the alveoli contains more oxygen

A

False, less oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why is there less oxygen at higher altitudes?

A

Carbon dioxide and water vapour decrease the alveolar oxygen by diluting the oxygen in the alveoli

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

True or False: At sea level, there is no difference in alveolar PO2 in unacclimatized and acclimatized individuals

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

True or False: At increased altitudes, the reduction in alveolar PO2 is lower in an unacclimatized person compared to an acclimatized person.

A

False, higher in an unacclimatized person

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

True or False: Alveolar ventilation increase much more in the acclimated person.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Up to an altitude of 10,000 feet, arterial oxygen saturation remains at least as high as ______.

A

90%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

True or False: Above 10,000 feet, arterial oxygen saturation falls rapidly.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How can you aid in breathing in more oxygen at higher altitudes?

A

Breathing pure oxygen instead of air, fills the space in the alveoli formerly occupied by nitrogen by oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the graph on arterial oxygen saturation and when breathing pure oxygen

A

Pure oxygen lasts longer before it falls off

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

______ occurs when oxygen levels in blood are low, less oxygen is available to the body’s tissue

A

Hypoxemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

______ is decreased oxygen in tissue.

A

Hypoxia

17
Q

At _______ feet in a unacclimatized person symptoms include, drowsiness, mental and muscle fatigue, headache and nausea.

A

12 000

18
Q

True or False: At 23,000 feet symptoms include twitching or seizures.

A

False, 18 000, 23 000 = coma

19
Q

_______ triggers compensatory responses in order to raise arterial PO2

A

Hypoxemia

20
Q

What are the 5 ways to people acclimate to low PO2

A

A greater increase in pulmonary ventilation

Increased number of red blood cells

Increased diffusing capacity of the lungs

Increased vascularity of the peripheral tissues

Increased ability of the tissues to use oxygen despite low PO2

21
Q

How do you increase pulmonary ventilation?

A

Immediate exposure to low PO2 stimulates the arterial chemoreceptors

Increases alveolar ventilation

Removing large quantities of carbon dioxide

Reducing PCO2 and increasing pH

22
Q

How do kidneys help to increase pulmonary ventilation?

A

Kidneys help maintain acid-base balance

Kidneys reduce hydrogen ion secretion and increase bicarbonate excretion

Kidneys will excrete bicarbonate to match the loss of hydrogen ion that accompanies the reduction in arterial PCO2

23
Q

How do you increase red blood cell production?

A

Kidneys secrete erythropoietin, stimulating erythrocyte synthesis

Increasing the concentration of hemoglobin in blood

Increasing oxygen carrying capacity of the blood

24
Q

True or False: Cardiac output increases immediately after a person ascends to high altitude, but decreases back to normal over a period of weeks

A

True

25
Q

Cardiac output returns to normal as blood ______ increases

A

hemocrit

26
Q

How does increased diffusing capacity after acclimatization work/

A

Increased pulmonary capillary blood volume

Expands capillaries and increases surface area that oxygen can diffuse into blood

Increased lung air volume

Expands surface area of the alveolar-capillary interface

Increase in pulmonary arterial blood pressure

Blood can enter more alveolar capillaries than normal

27
Q

How does peripheral circulatory system changes work?

A

Increased tissue capillarity

Growth of increased number of systemic circulatory capillaries in nonpulmonary capillaries (angiogenesis)

Capillarity is greatest in active tissues exposed to chronic hypoxia

Most pronounced in animals born and bred at high altitudes

28
Q

How does cellular acclimatization work/

A

Mitochondria increase

Cellular oxidative enzymes increase

High altitude acclimatized humans can utilize oxygen more effectively than sea level individuals

29
Q

What are some charcteristics of people living near high altitudes?

A

Barrel chested (increased lung volumes)

Increased chest size to body size

High ratio of ventilatory capacity to body mass

Larger hearts, greater cardiac output

Elevated hemoglobin levels

30
Q

True or False: Well acclimatized lowlanders cannot achieve work capacities at high altitudes equal to native people

A

True