Chapter 18: Gas Exchange and Transport Flashcards
remain relatively constant
Arterial blood O2 and CO2 levels
how much oxygen does the body consume at rest?
250 mL of O2 each minute
how much CO2 does the body produce at rest?
200 mL of CO2 each minute
how much air does the average adult inhale and how much reaches the alveoli?
- 6000mL/min
- 4200mL reaches alveoli
what are the steps of the pulmonary gas exchange?
1. Oxygen enters the blood at alveolar- capillary interface 2. Oxygen is trans- ported in blood dissolved in plasma or bound to hemoglobin inside RBCs. 3. Oxygen diffuses into cells 4.CO2 diffuses out of cells 5. CO2 is trans- ported dissolved, bound to hemoglobin, or as HCO3- 6. CO2 enters alveoli at alveolar-capillary interface.
states that the pressure exerted by a mixture of gasses is equal to the sum of the pressures exerted by the individual gases occupying the same volume.
Dalton’s Law-partial pressure of gases
are mixtures of different molecules
many gases
= proportion of pressure of entire gas that is due to presence of the individual gas
partial pressure of a gas
Ptotal=
P1 + P2 + P3 + … Pn
depends on fractional concentration of the gas
partial pressure of a gas
what is the equation for the total pressure of a gas mixture?
Pgas = %gas × Ptotal
what is the composition of air?
-79% nitrogen
21% oxygen
-Trace amounts of carbon -dioxide, helium, argon, and other gases
-Water can be a factor depending on humidity
Pair=
760 mm Hg = PN2 + PO2
PN2=
0.79 × 760 mm Hg = 600 mm Hg
PO2=
0.21 × 760 mm Hg = 160 mm Hg
how much of the air is CO2?
0.03%
PCO2=
0.0003 × 760 mm Hg = 0.23 mm Hg
what is the composition of air at 100% humidity?
Pair = 760 mm Hg = PN2 + PO2 + PH2O
what is PN2 at 100% humidity?
PN2 = 0.741 × 760 mm Hg = 563 mm Hg
what is PO2 at 100% humidity?
PO2 = 0.196 × 760 mm Hg = 149 mm Hg
what is PH2O at 100% humidity?
PH2O = 0.062 × 760 mm Hg = 47 mm Hg
what is PCO2 at 100% humidity?
PCO2 = 0.00027 × 760 mm Hg = 0.21 mm Hg
can exist in gas form or dissolved in a liquid
gas molecules
affects the amount of gas that goes into solution
partial pressure of a gas