PART 3\4 EXAM 2025 QUESTIONS AND
ANSWERS
_______ has a greater partial pressure in the pulmonary capillaries than in the alveoli, so it
diffuses into the _______. - ANS CO2: Alveoli
Despite the fact that the partial pressure difference is so much smaller for CO2, why is there as
much CO2 exchanged between the alveoli and blood as there is O2, ? - ANS CO2 is much
more soluble in blood than O2.
How would the partial pressures of O2 and CO2 change in an exercising muscle? - ANS The
partial pressure of O2 would decrease, and the partial pressure of CO2 would increase.
Which way would O2 and CO2 diffuse during internal respiration? - ANS O2 would diffuse
into the cells, and CO2 would diffuse into the systemic capillaries.
Internal and external respiration depends on several factors. Which of the following is NOT an
important factor in gas exchange? - ANS the molecular weight of the gas
Which statement is correct?
-During external respiration, equilibrium is reached for O2 when the partial pressure for O2 in
the pulmonary capillaries and the alveoli are the same.
-During external respiration, oxygen is unloaded from the blood.
-The greater the available surface area the lower the amount of gas exchange during internal
respiration.
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, -During internal respiration, carbon dioxide is unloaded from the blood. - ANS During
external respiration, equilibrium is reached for O2 when the partial pressure for O2 in the
pulmonary capillaries and the alveoli are the same.
Flow Chart - ANS -breathing air moves in the lungs
-oxygen diffuses into the alveoli
-oxygen enters red blood cells
-oxygen diffuses into the blood into the body
-carbon dioxide leaves the body
flow chart for oxygen transport - ANS -oxygen diffuses from alveoli into capillary
-oxygen enters red blood cell
-oxygen binds to hemoglobin
-oxygen is carried through blood vessels to a capillary
-oxygen diffuses into capillary
during inhalation - ANS the diaphragm and rib muscles contract.
From which structures do oxygen molecules move from the lungs to the blood? - ANS alveoli
which statement is correct?
-In the blood, oxygen is bound to hemoglobin, a protein found in red blood cells.
-Carbon dioxide diffuses from the alveoli into surrounding capillaries.
-Oxygen is released from the mitochondria as a product of cellular respiration.
-As oxygen diffuses from the lungs into capillaries, blood becomes deoxygenated.
-Oxygen diffuses from large blood vessels into the body's cells. - ANS in the blood, oxygen is
bound to hemoglobin, a protein found in red blood cells
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