13 - Volumes and Pressures - VOCABULARY Flashcards

Vocabulary flashcards covering partial pressures, gas laws, and related concepts from the lecture on volumes and pressures.

Partial pressure

The pressure exerted by a single gas within a mixture; determined by its mole fraction in the total gas; total pressure equals the sum of all partial pressures (Dalton's Law).

PIO2

Partial pressure of oxygen in inspired air; equals the fractional concentration of O2 in inspired air multiplied by the total pressure (e.g., 0.21 × 101 kPa ≈ 21 kPa at sea level).

PvO2

Partial pressure of oxygen in venous blood.

PvCO2

Partial pressure of carbon dioxide in venous blood.

PAO2

Partial pressure of oxygen in the alveolus.

PACO2

Partial pressure of carbon dioxide in the alveolus.

PaO2

Partial pressure of oxygen in arterial blood.

PaCO2

Partial pressure of carbon dioxide in arterial blood.

Total pressure

The sum of the partial pressures of all gases in a mixture (Ptotal = P1 + P2 + …).

Dalton's Law of Partial Pressures

Each gas in a mixture exerts its own partial pressure; the total pressure is the sum of the partial pressures.

Charles’s Law

At constant pressure, gas volume increases with temperature (V ∝ T).

Boyle’s Law

At constant temperature, pressure is inversely proportional to volume (P1V1 = P2V2).

Dry gas

The gas portion after removing water vapor; Pdry = Ptotal − PH2O.

PH2O

Water vapour pressure; in the lungs at 37°C it is 6 kPa, reducing the effective pressure of other gases.

BTPS

Body Temperature and Pressure, Saturated; conditions for gases in the lungs; volumes are recorded under BTPS.

ATPS

Ambient Temperature and Pressure, Saturated; volumes collected at ambient temperature/pressure with water vapour saturated; conversions to BTPS use Boyle-Charles formula.