2B exercise physiolgy

Loading of O2 onto hemoglobin in red blood cells  occurs when O2 diffuses from the air in the  __________ to the surrounding capillaries

alveoli

The volume of air inspired or expired per breath is

tidal volume

Dead space air is

air in the airway passages in which gas exchange with the capillaries does not occur

If dead space volume is relatively constant but tidal volume increases dramatically (as it does during aerobic exercise), the ratio of dead space volume to tidal volume

decreases

Minute ventilation (total volume of inspired/expired air in a minute) is

breathing rate (breaths per minute) x tidal volume (liters per breath)

The Valsalva maneuver

all of the options

The rate of gas diffusion from air to a liquid is dependent on

partial pressure differential from gas from the air to the liquid, soulibility of gas in the liquid, so both

PO2 in the alveoli is lower than the atmospheric PO2 because

 

humidification of the inspired air slightly lowers PO2, the inspired air mixes with partially-deoxygenated dead space air on the way to the alveoli, both

If you were to massively increase your ventilatory volume by hyperventilating (while resting), you could

increase alveolar PO2

Hyperventilation (at rest)

allows more CO2 exhalation, lowering blood PCO2

If blood PCO2 is a stimulatory factor for ventilation, then hyperventilation that lowers blood PCO2 would subsequently (immediately after hyperventilation ends)

lower ventilation (rate of breathing x tidal volume)

A decrease in blood pH

promotes unloading of O2 from hemoglobin

The Bohr effect described in the previous question is much more pronounced

 

at the PO2 encountered in the peripheral tissues (e.g. skeletal muscle)

This factor promotes unloading of O2 from hemoglobin

 

higher temperature, higher concentration of 2,3-diphosphoglycerate in red blood cells, lower pH, all of the above

Compared to rest, aerobic exercise

increases the a-v O2 difference across skeletal muscle

Given the hemoglobin levels shown for men and women in table 13.3

men have a greater oxygen carrying capacity in the blood

Most CO2 is carried from working muscle to the lungs

after being converted to bicarbonate

Red blood cells have a transport protein that exchanges bicarbonate for

Cl-

When an athlete is doing steady-state aerobic exercise at about 60% VO2max, her SaO2 (oxygen saturation of hemoglobin in arterial blood) is 96%, which is the same as her SaO2 when she’s not exercising.  However, her minute ventilation is much higher when she’s exercising than when she’s resting.  Sensing of exercise-related changes that lead to increased ventilation could include all of the following EXCEPT

sensing of decreased PO2 by arterial chemosensors

Increased ventilation in a resting person at high altitude (compared to the resting person at sea level) is dependent on sensing of

PO2

Minute ventilation is a product of

both, frequency of breathing (breaths per minute), tidal volume (volume per breath)

As aerobic exercise intensity increases

both, frequency of breathing (breaths per minute), tidal volume (volume per breath)

Which is dramatically lower at high altitude compared to sea level?

PO2 of atm air

Minute ventilation increases immediately and dramatically at the start of exercise before there are changes in blood PO2, VCO2, pH, or [K+] and drops substantially and immediately when exercise ends.  These phenomena suggest a role for _____________ in ventilatory control.

central command

A decrease in arterial PO2 in elite endurance athletes at high work intensities could be a result of

all of the above

Buffers in blood plasma include

all of the above

When the carbonic anhydrase reaction proceeds in the direction of formation of bicarbonate from CO2, this

decreases pH

Hyperventilation blows off an excess of CO2, causing the carbonic anhydrase reaction to proceed in the direction of CO2 production from bicarbonate.  This

increases pH