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Flashcards in Gas Laws Deck (20):
1

capacity

the sum of 2 or more volumes

2

factors influencing total lung capacities

body size

age

gender

race

3

describe the spirometry curves and name the major measurements of breathing

4

ideal gas law

relates the pressure (P), volume (V), and temperature (T) of a gas to the number (n) of moles of gas by a proportionality factor, the gas constant (R)

PV = nRT

5

standart temperature and pressure

1 atm and 0 degrees C

6

volume of one mole of any gas at standard temperature

22.4 liters

7

Dalton's law

gas species in a mixture act independentl to exert a partial pressure (P) equal to the pressure this same gas would exert if it occupied the total volume of the gas mixture in the absence of other components

PB = PN2 + PO2 + PCO2 + PH2O

PB is barometric pressure

8

PO2 in dry atmospheric air at 760 mmHg barometric pressure

159 mmHg

9

PO2 in air saturated with water vapor at 37 degrees C and 760 mmHg

149 mmHg

10

typical values for adult residual volume, functional residual capacity

RV = 1500

FRC = 3000

TLC = 6000

11

Why do RV and FRC increase with age, but TLC doesn't?

Decreased lung elastic tissue - increased compliance (i.e. less lung recoil)

12

Helium dilution

helium at a known concentration and volume in the spirometer is brought into equilibrium with the lung

based on concentration measurements, the capacity of the lung can be measured

Vlung = Vspir x [([He]initial/[He]final) - 1]

13

fraction gas concentrations in dry room air

1.0 = FN2 + FO2 + FCO2

Fg = Pg/PB

FN2 = 0.78

FO2 = 0.21

FCO2 = 0.0003

14

oxygen fraction equation

FO2  = PO2/(PB - PH2O)

15

BTPS

body temperature, ambient pressure, and saturated with water vapor

volumes of ventilated gases are expressed in BTPS conditions

16

STPD

standard temperature (0 degrees C or 273 degrees K)

standard pressure (760 mmHg)

dry (no water vapor present)

metabolic rates are expressed by gas volumes in STPD conditions since volumes at STPD are directly related to the number of millimoles of oxygen consumed or carbon dioxide produced (22.4 mL per mmole)

17

ATPS

ambient temperature, ambient pressure and saturated with water vapor

many respiratory variables are measured in ATPS conditions and must be converted to BTPS or STPD conditions as appropriate

18

Henry's Law

relates the concentration (C) of a gas in solution to its partial pressure

Cg = K*Pg

where Cg = concentration of dissolved gas, K = proportionality constant (termed the solubility coefficient) for the dissolved gas, Pg = partial pressure of the gas

19

determinants of diffusion of gases across media

when diffusion occurs between different media, gas diffuses down the potential graident that is most closely related to its partial pressure gradient, not necessarily down a concentration gradient

20

convection

transmission of energy or mass by a medium involving movement of the medium itself

the circulatory movement that occurs in a fluid at a non-uniform temperature owing to the variation of its density and the action of gravity