Lab Exam 2- Lab 10

Question 1

acute ascent to altitude results in

Answer 1

environmental hypoxia

Question 2

the reduction in the amount of oxygen at altitude is due to

Answer 2

reduced barometric pressure at increasing altitudes

Question 3

the lower barometric pressure reduces the

Answer 3

partial pressure of inspired O2 (PiO2)

Question 4

hypobaric hypoxia

Answer 4

the hypoxia associated with terrestrial altitude exposure

Question 5

does the percentage of O2 in ambient air change at altitude

Answer 5

NO- the %O2 in ambient air is always constant at 20.93% regardless of altitude

Question 6

physiological responses to altitude are dependent on

Answer 6

the severity of hypoxia

Question 7

if a sea level resident travelled to Mount Everest what physiologic changes would be seen

Answer 7

loss of consciousness within minutes to hours

Question 8

what happens physiologically to a person with gradual ascent and chronic altitude exposure

Answer 8

physiological adaptations - acclimatization
enables us to successfully tolerate altitudes that would cause major problems acutely

Question 9

what condition is focused on in the altitude lab

Answer 9

acute hypoxia

Question 10

what 3 parameters are required to calculate PiO2

Answer 10

barometric pressure (Pb)
water vapor pressure (PH2O) in inspired air
% of O2 in the environment

Question 11

barometric pressure is dependent on

Answer 11

altitude

Question 12

water vapor pressure in inspired air (PH2O)

Answer 12

47 mmHg *** independent of altitude

Question 13

% O2 in the environment

Answer 13

20.93% *** independent of altitude

Question 14

equation to calculate PiO2

Answer 14

PiO2= (Pb-PH2O) * %O2(as a decimal)

or

PiO2= (Pb-47)*0.2093

Question 15

how does an acute reduction in PiO2 affect O2 levels in the blood

Answer 15

reduced PiO2 leads to a decrease in alveolar partial pressure of O2 (PAO2) which leads to a reduction in the partial pressure of O2 in arterial blood (PaO2)

Question 16

what does SaO2 stand for

Answer 16

arterial Hb-O2 saturation

Question 17

what is a major determinant of arterial hemoglobin O2 saturation (SaO2)

Answer 17

PaO2

Question 18

shape of O2-Hb saturation curve

Answer 18

sigmoidal

Question 19

at the top of the O2-Hb saturation curve, what is the effect of small changes in PaO2

Answer 19

minimal effect

Question 20

at the steep portion of the O2-Hb saturation curve, what is the effect of small changes in PaO2

Answer 20

large effects on SaO2

Question 21

arterial oxygen content (CaO2) is determined by 3 parameters

Answer 21

[Hb]
SaO2
amount of O2 dissolved in plasma

Question 22

PaO2 influences ____

Answer 22

SaO2 and determines the amount of O2 dissolved in plasma

Question 23

compare the amount of O2 dissolved in plasma vs bound to Hb

Answer 23

the amount of O2 dissolved in plasma is extremely small compared to the amount bound to Hb

Question 24

in this weeks lab what are we examining

Answer 24

the changes in SaO2 heart rate, ventilation, BP, and substrate utilization at rest and during submaximal exercise with stimulated altitude exposure

*we are simulating high altitude using normobaric hypoxia

Question 25

what does PaO2 stand for

Answer 25

partial pressure of O2 in arterial blood

Question 26

what does CaO2 stand for

Answer 26

arterial O2 content

Question 27

physiological response to acute altitude exposure

Answer 27

decrease in PaO2, SaO2, and CaO2

Question 28

acute altitude exposure effects on max O2 uptake

Answer 28

VO2max is reduced with acute altitude exposure, with the severity of the reduction greater at higher elevations

Question 29

% reductions in VO2 max: trained vs untrained

Answer 29

endurance trained athletes have a higher % reduction in VO2 max than untrained individuals

Question 30

the decrease in VO2max at acute altitude exposure does what to intensity

Answer 30

increases the relative intensity of any given absolute (submaximal) power output at altitude

Question 31

HR response to acute altitude exposure

Answer 31

an increase in resting HR and elevation in HR at any given absolute submaximal power output

Question 32

what happens to max HR with acute altitude exposure

Answer 32

no change

Question 33

what are the main factors in the blood influencing ventilation rate at sea level

Answer 33

PaCO2 and arterial pH *peripheral chemoreceptors that reside in aortic/carotid bodies respond to low PaO2 and play a predominant role in ventilatory response to hypoxia

Question 34

the fall in PaO2 at altitude results in

Answer 34

an increase in ventilation at rest and all absolute workloads compared to sea level

Question 35

compare the increase in ventilation during exercise at altitude vs at rest

Answer 35

the increase in ventilation during exercise at altitude is significantly larger than the increase in ventilation at rest

Question 36

substrate utilization response to acute altitude exposure

Answer 36

increases CHO utilization during absolute submaximal exercise intensities

Question 37

BP response to acute altitude exposure

Answer 37

MAP may decrease slightly * although increase in SNS activity with acute altitude exposure are expected to contribute to peripheral vasoconstriction, local factors are released that blunt peripheral vasoconstriction leading to small reductions in TPR and BP

Question 38

variability in individuals response to acute altitude exposure

Answer 38

the level of hypoxia incurred at a given altitude varies between individuals

Question 39

normobaric hypoxia

Answer 39

simulating altitude without going to altitude *artificially modifying the %O2 by providing subjects with a hypoxic (<20.93%) gas mixture in lab setting pressure = normal but the PiO2 is reduced due to artificial reduction in the % inspired O2

Question 40

2 conditions measured in this lab

Answer 40

normoxic exercise and hypoxic exercise at two different submaximal workloads - 50 W and 100 W

Question 41

what variables are measured at rest

Answer 41

BP HR Ve O2 saturation

Question 42

what variables are measured during normoxic/hypoxic exercise

Answer 42

BP HR VE O2 saturation RPE

Question 43

how long are subjects exercising at each submaximal workload

Answer 43

4-5 minutes

Question 44

how long will the subject rest for before starting exercise

Answer 44

10 minutes

Question 45

during the hypoxic protocol, what is the components of the air breathed in made of

Answer 45

15% O2 / 85% N2 gas simulating the hypoxic condition experienced at Pikes Peak (4300 m, 14,110 ft above sea level)

Question 46

hypoxic conditions effect in VT / LT thresholds

Answer 46

cause a leftward shift VT and LT are reached at lower absolute workloads during hypoxic exercise

Question 47

hypobaric hypoxia

Answer 47

reduce pressure in hypobaric chamber

Question 48

normobaric hypoxia

Answer 48

reduce fraction of O2 in inspired gas