Humans at High Altitude (Lecture 18)

Question 1

True or False: Atmospheric pressure decreases at high altitudes

Answer 1

True

Question 2

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

Answer 2

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

Question 3

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

Answer 3

Decreases

Question 4

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

Answer 4

True

Question 5

True or False: Acclimatized people can increase their ventilation

Answer 5

True

Question 6

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

Answer 6

False, less oxygen

Question 7

Why is there less oxygen at higher altitudes?

Answer 7

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

Question 8

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

Answer 8

True

Question 9

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

Answer 9

False, higher in an unacclimatized person

Question 10

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

Answer 10

True

Question 11

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

Answer 11

90%

Question 12

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

Answer 12

True

Question 13

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

Answer 13

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

Question 14

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

Answer 14

Pure oxygen lasts longer before it falls off

Question 15

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

Answer 15

Hypoxemia

Question 16

______ is decreased oxygen in tissue.

Answer 16

Hypoxia

Question 17

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

Answer 17

12 000

Question 18

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

Answer 18

False, 18 000, 23 000 = coma

Question 19

_______ triggers compensatory responses in order to raise arterial PO2

Answer 19

Hypoxemia

Question 20

What are the 5 ways to people acclimate to low PO2

Answer 20

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

Question 21

How do you increase pulmonary ventilation?

Answer 21

Immediate exposure to low PO2 stimulates the arterial chemoreceptors

Increases alveolar ventilation

Removing large quantities of carbon dioxide

Reducing PCO2 and increasing pH

Question 22

How do kidneys help to increase pulmonary ventilation?

Answer 22

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

Question 23

How do you increase red blood cell production?

Answer 23

Kidneys secrete erythropoietin, stimulating erythrocyte synthesis

Increasing the concentration of hemoglobin in blood

Increasing oxygen carrying capacity of the blood

Question 24

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

Answer 24

True

Question 25

Cardiac output returns to normal as blood ______ increases

Answer 25

hemocrit

Question 26

How does increased diffusing capacity after acclimatization work/

Answer 26

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

Question 27

How does peripheral circulatory system changes work?

Answer 27

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

Question 28

How does cellular acclimatization work/

Answer 28

Mitochondria increase Cellular oxidative enzymes increase High altitude acclimatized humans can utilize oxygen more effectively than sea level individuals

Question 29

What are some charcteristics of people living near high altitudes?

Answer 29

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

Question 30

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

Answer 30

True