Part IV Flashcards
Which is thicker, pulmonary artery or aorta? By how much?
Aorta, 3x
Which is thicker, right ventricle or left ventricle? By how much?
Left, 3x
All pulmonary arteries have a larger what?
Lumen
Why do pulmonary arteries have a larger lumen?
It makes them more compliant, they operate under a lower pressure and they can accommodate 2/3 of the stroke volume from the right ventricle
Pulmonary veins have similar compliance to what?
Systemic veins
What is the total pulmonic blood volume?
450mL or 9% of total blood volume
What kind of function does the pulmonary system have?
Reservoir function
What makes a reservoir function special?
It allows the pulmonary system to hold from 1/2-2x the total pulmonic blood volume
Shifts in pulmonic volume can occur from what?
Pulmonic to systemic or vice versa
What can increase pulmonic volume by 100%? Why?
Mitral stenosis because the blood can’t get back to the heart
The shift in pulmonic blood flow has a great effect on what?
Pulmonary ventilation
What does the bronchial artery stem from?
Thoracic aorta
What do the systemic bronchial arteries supply.?
Supporting tissue, airways of the lung
What percent of CO is bronchial arteries taking up?
2%
Venous drainage goes into what?
Azygous or pulmonary veins
What happens when there is drainage into the pulmonic veins?
It causes the left ventricular output to be slightly higher than than the right ventricular output. Some deoxygenated blood also gets mixed in with the oxygenated pulmonic blood
Why do the lungs receive excess blood flow?
It receives both total pulmonic flow and some systemic flow simultaneously
What is the total flow to the lungs equation?
Right ventricular output (pulmonic flow) + bronchial artery (small portion, systemic flow from aorta
Right ventricular output is equal to what?
Cardiac output
What percent of blood flow is bronchial artery?
1-2%
Where do pulmonary lymphatics extend to?
All supportive tissue of the lungs and courses through the hilum
What pulmonary lymphatics do?
Removes plasma filtrate, particulate matter absorbed from alveoli and escaped proteins from the vascular system
How does pulmonary lymphatics maintain negative pleural pressure?
Pulls alveolar epithelium against capillary endothelium “respiratory membrane”
What is normal pulmonary artery pressure?
25/8
What is mean pulmonary artery pressure?
15mmHg
What is mean pulmonary capillary pressure?
7mmHg
What is major pulmonary veins and left atrium mean pressure?
2mmHg
Cardiac output equals what?
Pulmonary blood flow
If cardiac output equals pulmonary are blood flow, what does that mean when something affects CO?
Pulmonic blood flow will also be affected
Blood is driven to what part of the lung?
Well ventilated areas
How is blood driven to a more well ventilated area of the lung?
Low alveolar oxygen causes release of a local vasoconstrictor, which automatically redistributes blood to better ventilated areas
SNS causes what to the lungs?
Vasoconstriction
3-30Hz increases what about 30%?
Pulmonary blood pressure
What is pulmonary blood pressure mediated by?
Alpha receptors
The alpha response on pulmonary blood pressure is abolished at how many Hz? What happens at that number?
30Hz, beta receptors are unmasked
Parasympathetics cause what of the lung?
Vasodilation
Low alveolar oxygen causes what?
Major constrictor effect on pulmonary vascular smooth muscle
When does capillary increase in the lung?
when it gets toward the base of the lung because of gravity
Describe Zone 1.
there is no flow in zone 1, the alveolar pressure is greater than the capillary pressure. it normally doesn’t exist
Describe Zone 2.
there is intermittent flow in zone 2, the capillary pressure is greater than the alveolar pressure during systole and the capillary pressure is less than the alveolar pressure during diastole
Describe Zone 3.
there is continuous flow in zone 3 as you go toward the base, capillary pressure is greater than alveolar pressure
During exercise, what zone is the entire lung in?
zone 3
