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RESP105 Ch. 9
Ventilation-Perfusion Relationships
Question | Answer |
---|---|
The normal alveolar ventilation is about | 4/Lmin |
The normal pulmonary capillary blood flow is about | 5/Lmin |
the average overall ventilation-perfusion ratio is | 4:5 or 0.8 |
In the normal individual in the upright position, the V/Q ration in the upper lung is | higher than 0.8 |
In the normal individual in the upright position, the V/Q ratio in the lower lung region is | is lower than 0.8 |
In the upright lung, the V/Q ratio progressively | decreases from top to bottom |
The PAo2 is determined by the balance between | the amount of oxygen entering the alveoli and it's removal by capillary blood flow |
the PAco2 is determined by the balance between | The amount of carbon dioxide that diffuses into the alveoli from the capillary blood and it's removal from the alveoli by means of ventilation. |
An increase V/Q ratio can develp from either | an increase in ventilation or a decrease in perfusion |
When the V/Q ratio increases the PAo2 _______ and the PAco2 _______ | PAo2 rises and the PAco2 falls |
The PAo2 increases because it does not | diffuse into the blood as fast as it enters (or is ventilated) into the alveolus |
the PAco2 decreases because it is | washed out of the alveoli faster than it is replaced by the venous blood |
In the upright lung, an increased V/Q ratio is found in the | upper lung regions |
a decreased V/Q ratio can develop from either | a decrease in ventilation or an increase in perfusion |
when the V/Q ratio decreases, PA02 ____ and the PAco2 | PAo2 falls and PAco2 rises |
The PAo2 decrease because it moves | out of the alveolus & into the pulmonary capillary blood faster than it is replenished by ventilation |
The PAco2 increases because it moves | out of the capillary blood & into the alveolus faster than it is washed out of the alveolus |
In the upright lung, a decreased V/Q ratio is found in the | lower lung regions |
internal respiration is defined as | gas exchange between the systemic capillaries & the cells |
Under normal circumstances, about ___mL of oxygen are consumed by the tissue cells in 1 minute. | 250 |
Normally the tissue cells produce about ____ mL of carbon dioxide produced (Vco2) | 200 |
respiratory quotient is defined as the | ratio between the volume of carbon dioxide produced (Vco2) |
The respiratory quotient is expressed as | RQ= Vco2 _____ Vo2 |
external respiration is defined as the | gas exchange between the pulmonary capillaries & the alveoli |
respiratory exchange ratio is defined as the | quantity of O2 &CO2 exchanged during a period of 1 minute |
some pulmonary disorders that increase v/q ratio | pulmonary emboli partial or complete obstruction extrinsic pressure on the pulmonary vessels destruction of pulmonary vessels decreased cardiac output |
pulmonary disorders that decrease v/q ratio | obstructive lung disorders restrictive lung disorders hypoventilation |