Module 3: Respiration Flashcards
What is gas exchange driven by?
Pressure gradients at both PULMONARY capillaries and SYSTEMIC capillaries
Alveoli PO2 = ____ mmHg
103
Describe the PO2 levels of pulmonary capillaries as they return from the tissues and when they leave to go to the rest of the body
PO2 of blood returning from tissues = 40 mmHg
PO2 of blood leaving pulmonary capillaries is saturated with O2 so it goes up to 100 mmHg
Alveoli PCO2 = _____ mmHg
40
Describe the PCO2 levels of pulmonary capillaries as they return from the tissues and when they leave to go to the rest of the body
PCO2 of blood returning from tissues = 45 mmHg
PCO2 of blood leaving pulmonary capillaries has REDUCED it’s CO2 so that it it is 40 mmHg
The tissue PO2 can be as low as ___ mmHg (depending on _____)
20 mmHg
metabolism demand
Tissue capillary PO2 of blood entering tissues is:
90-100 mmHg
Blood leaving the tissue capillaries that has already delivered its O2 is approx: ____ mmHg
40
Tissue PCO2 = ____ mmHg (depending on ____)
46 mmHg
metabolism demand
Tissue capillary PCO2 is ____ mmHg
40 mmHg
Blood leaving the tissue capillaries that has increased it’s CO2 now is approx. ____ mmHg
45 mmHg
Percentage of Oxygen in atmospheric air:
Calculate it’s partial pressure
21%
PO2 = 760 x 21% = 159 mmHg
Percentage of CO2 in atmospheric air
Calculate it’s partial pressure
.03%
PCO2 = 760 x .03% = .22 mmHg
What is the percentage of O2 and CO2 in alveolar pressures?
O2 = 14.5% (760-47)(14.5%) CO2 = 5.5%
What is an average resting Cardiac Output (CO)
5 L/min
What is the average exercise cardiac output (CO)?
up to 25 L/min
Which is more compliant with alveoli ventilation: the base or the apex of the lungs?
Why?
The base because the alveoli are smaller and have a reduced surface tension and therefore easier to inflate
The apex inflates during extremes of ventilation (WOB/accessory muscles, etc)
Pulmonary circulation and function are ____ dependent.
Gravity
What happens if alveolar gas pressure exceeds capillary pressure?
Perfusion slows or stops
The capillary “collapses” or “is compressed” thus blood flow stops
Where are the three zones of ventilation and perfusion located in the lung?
Zone I: At apex (small area)
Zone II: Area above left atria
Zone III: Base of the lung
Zone I: describe relationship between pressures and what happens to perfusion
Alveolar pressure > arterial capillary pressure > venous capillary pressure
Perfusion: is STOPPED by the alveolar pressure
Zone II: relationship between pressures and what happens to perfusion
Arterial capillary pressure > alveolar pressure > venous capillary pressure
Perfusion: is SLOWED DOWN by alveolar pressure
Zone III: relationship between pressures and what happens to perfusion:
Arterial capillary pressure > venous capillary pressure > alveolar pressure
Perfusion: is NOT EFFECTED by the alveolar pressure