3 - Pulmonary Blood Flow Flashcards
Alveolar capillaries receive blood from the _______ _______.
Right Ventricle
Alveolar capillary blood has (HIGH/LOW) O2 and (HIGH/LOW) CO2.
Low
High
There are millions of alveolar capillaries and they are involved in the exchange of O2 and CO2 between the ________ and the ________.
Blood
Air
Extra-Alveolar (bronchial) capillaries receive blood from the ________ ________.
Left Ventricle
Extra-alveolar capillary blood has (HIGH/LOW) O2 and (HIGH/LOW) CO2.
High
Low
What is the job of the extra-alveolar capillaries?
To deliver O2 and CO2 to the tissue of the lungs.
Extra-alveolar capillary blood returns to the heart in the ________ _______, creating venous admixture. This reduces the _______ of the arterial blood by a few mmHg and increases the _______ to a small degree.
Pulmonary veins
PaO2
PaCO2
What is the PaO2 levels in the artery leading to the alveolar and extra-alveolar capillaries?
Alveolar = Low Extra-alveolar = High
What is the PaCO2 levels in the artery leading to the alveolar and extra-alveolar capillaries?
Alveolar = High Extra-alveolar = Low
How do the alveolar and extra-alveolar capillaries return blood to the heart?
Pulmonary veins to the Left Ventricle
What is the blood gas levels in the vein from the alveolar and extra-alveolar capillaries?
Alveolar = High PaO2 and Low PaCO2 Extra-alveolar = Low PaO2 and High PaCO2
***This creates a venous admixture due to the extra-alveolar blood gas levels.
What is the equation for pulmonary BP?
PBP = CO x PVR
PBP = Pulmonary blood pressure (25/15 mmHg) CO = Cardiac Output (at rest 5 L/min) PVR = resistance to blood flow through lungs (very low)
PVR can depend on the number of capillaries open at a given time. During exercise, the PVR (INCREASES/DECREASES) as more pulmonary capillaries open up to accommodate the increased cardiac output.
Decreases
PVR also depends on the lung ________.
Volume
At low or very high lung volumes, the resistance (INCREASES/DECREASES) a little because the stretch of the tissue compresses the capillaries. Just like a rubber band gets a little thinner when stretched, the diameter of the capillaries decreases a little.
Increases
Why does a person pass out if they stand with their knees locked too long?
– Gravity was acting on their blood, pulling it into their legs while they stood there with their knees locked.
– They passed out because less blood was returning to their heart (and therefore the brain).
***Not locking their knees will allow them to use skeletal muscle activity to increase the blood flow from their legs back up into their thorax.