Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
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 |
|
V
|
gas volume
|
|
Q
|
Blood volume
|
|
P
|
pressure of a gas in a gas or in a liquid
|
|
F
|
Concentration of a gas in a gas phase (fraction/percent)
|
|
C
|
Concentration of a gas in a liquid, either in chemical equilibrium or dissolved.
|
|
S
|
% saturation of hemoglobin with oxygen
|
|
f
|
Breathing frequency - breaths/min
|
|
Eupnea
|
Normal breathing at rest
|
|
Hyperpnea
|
Increased breathing
|
|
Hypopnea
|
Decreased breathing
|
|
Dyspnea
|
Awareness of breathing
|
|
Tachypnea
|
Increased freq of breathing
|
|
Hyperventilation
|
Breathing in excess of requirements of metabolism resulting in decreased PaCO2
|
|
Hypoventilation
|
Breathing insufficient for requirements of metabolism resulting in increased PCo2
|
|
Hypoxia
|
Reduced oxygen in inspired air
|
|
Hypoxemia
|
Reduced oxygen in arterial blood
|
|
Hypercapnia
|
Increased PaCO2 or PACO2
|
|
Apnea
|
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?
|
-Mechanics
-Control |
|
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:
|
-Diffusion
-Pressure gradients |
|
What % of gas in the atmosphere is oxygen?
|
21%
|
|
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?
|
~8
|
|
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.
|