Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

76 Cards in this Set

  • Front
  • Back
What is the function of the respiratory system? (2 parts)
1. Oxygenation of blood
2. Elimination of CO2
gas volume
Blood volume
pressure of a gas in a gas or in a liquid
Concentration of a gas in a gas phase (fraction/percent)
Concentration of a gas in a liquid, either in chemical equilibrium or dissolved.
% saturation of hemoglobin with oxygen
Breathing frequency - breaths/min
Normal breathing at rest
Increased breathing
Decreased breathing
Awareness of breathing
Increased freq of breathing
Breathing in excess of requirements of metabolism resulting in decreased PaCO2
Breathing insufficient for requirements of metabolism resulting in increased PCo2
Reduced oxygen in inspired air
Reduced oxygen in arterial blood
Increased PaCO2 or PACO2
Cessation of breathing
Periodic Breathing
Alternate periods of increased and decreased breathing
Avagadro's hypothesis for gas behavior:
For all gases, an equal # of molecules in the same space and at the same Temp will exert the same Pressure
Dalton's Law for gas behavior:
In a gas mixture, the pressure exerted by each individual gas in a space is independent of the pressures of other gases in the mixture.
Boyle's Law for gas behavior:
As a gas is compressed, its volume decreases in proportion to its pressure increase.
Charles Law:
If a vol of gas is kept constant, the pressure of the gas is proportional to temp.
Ideal Gas Law:
PV = nRT
Henry's Law:
The conc of a dissolved gas is equal to the partial pressure of the gas times the solubility coefficient.
How many molecules of gas are in a mole, and how much volume will they occupy? At what pressure?
6 x 10^23 molecules in a vol of 22.4 L at a temp of 0'C and pressure of 760 mm Hg.
Define Breathing:
Movement of air from the Atmosphere to the lungs and alveoli
What is V(E)?
Pulmonary ventilation
What is V(A)?
Alveolar ventilation
What is V(D)?
Dead space ventilation
What 2 things affect breathing?
What structure mainly controls breathing?
The brainstem
What happens after air enters the lungs/alveoli via breathing?
Alveolar-Capillary exchange
What 2 factors determine or influene alveolar-capillary exchange?
-Diffusing capacity
-Ventilation-perfusion matching
How is oxygen transported in the blood?
By the action of the heart pumping.
2 factors that determine how blood gas is transported:
-How much gas is DISSOLVED
-How much gas is bound to HEMOGLOBIN
What happens after blood transport of gases?
Capillary-tissue exchange.
2 factors that influence Capillary-Tissue exchange:
-Pressure gradients
What % of gas in the atmosphere is oxygen?
What is the concentration of O2 in the atmosphere?
21% x 760 mm Hg = 150 mm Hg
What is the normal pressure of O2 in alveoli and arterial blood?
~100 mm Mg
What is the normal mixed venous Po2?
about 45 mm Hg
What is the normal atmospheric PCo2?
0 mm Hg
What is the normal alveolar and arterial PCo2?
40 mm Hg
What is the normal mixed venous PCo2?
A little above 40 mm Hg
Why do Alveolar PO2 and PCo2 levels differ from atmospheric values? Why not the same?
(3 reasons)
1. Dead space
2. Functional residual volume
3. Continuous O2 usage and CO2 production
Why is arterial PO2 slightly less than alveolar PO2?
Because of bronchial venous admixture
Why is mixed venous PO2 less than arterial PO2?
Because of O2 utilization (duh)
Why aren't the changes in PCo2 in arterial and mixed venous as significant as the changes in PO2 values?
Because the O2 and CO2 hemoglobin dissociation curves have different shapes.
How many CO2's are produced for every 10 O2 used normally?
What does/doesn't determine arterial and alveolar PO2 and PCO2?
The RESPIRATORY SYSTEM - not hemoglobin.
What does hemoglobin determine?
Mixed venous PO2 levels - after oxygen has been dissociated from hemoglobin.
So how will the pressure gradients in an anemic individual compare to normal?
All same except MIXED VENOUS PO2 levels will be lower.
Why are mixed venous PO2 and PCO2 gas pressures different in the anemic individual?
Because each unit of blood carries less O2 and CO2 in bound form.
What is the mixed venous O2 level in an anemic individual compared to normal?
about 20 instead of 45 mm Hg.
What is the single most best way to assess whether the lung system is meeting its objective?
Look at alveolar and arterial PCO2
How do PO2 levels in a person at high altitude compare to those in a normal person?
They will be much lower at each step in the transfer path.
Why are PO2 levels lower when at high altitude?
Because there are fewer O2 molecules in the atmosphere at high altitude compared to sea level.
What is the atmospheric PO2 at pike's peak?
~80 mm Hg (instead of 150!)
What are the alveolar, arterial, and mixed venous Po2 levels in a person at pike's peak?
Alveolar = 60 mm Hg
Arterial = 50 mm Hg
Mixed Venous = 35 mm Hg
How come the difference in alveolar PO2 is not as striking even though Atmospheric PO2 is much lower than at normal sea level?
Because the chemoreceptors are stimulated to hyperventilate and compensate for hypoxia
Why is the drop from arterial PO2 to Mixed venous PO2 less than normal?
Because the Hb-O2 dissociation curve shifts to increase delivery.
Why is PCO2 decreased at high altitude?
Due to hyperventilation - blowing off more CO2.
What are the arterial and alveolar PCO2 levels in a resident of Pike's peak?
~20 mm Hg (instead of 40)
How would you know if a person is hypoventilating, based on comparing their PO2 and PCo2 gas gradients to normal?
-Alveolar and arterial PO2 would be decreased to about same degree as PCO2 increase
-There would be no change in mixed venous levels - not a problem with hemoglobin.
When does everyone undergo hypoventilation normally?
When sleeping.
What is Farmer's Lung disease?
Abnormal alveolar-capillary gas exchange
What is the hallmark of inadequate gas exchange from alveoli to capillaries?
A significant difference between alveolar and arterial PO2 levels
What happens to alveolar and arterial PO2 levels in farmer's lung disease?
-Alveolar PO2 will be increased

-Arterial PO2 will be decreased
(both normally close to 100)
What does the reduced arterial PO2 stimulate?
Increased breathing
What results from the increased breathing?
Increased ALVEOLAR PO2 and decreased PCO2 (blowing it off), but not arterial because exchange is just abnormal.
Why isn't mixed venous PO2 reduced as much as arterial PO2 in farmer's lung disease?
Because the Hb-O2 dissociation curve shifts to the steep portion for better release.
What's the best way to tell whether a person is hyperventilating or hypoventilating?
Look at alveolar/arterial PCO2 - will be increased if hypoventilating, and decreased if hyperventilating. O2 levels won't always tell the truth.
How do PO2 levels in a person with COPD compare to normal? Why?
All are lower - because there is poor Atm->alveolar exchange as well as alveolar->arterial.
How do PCo2 levels in a person with COPD compare to normal? Why?
All PCo2 levels are INCREASED b/c patient is hypoventilating - cannot increase breathing so not blowing off CO2 like farmer.