Lecture 23 - Pulmonary Circulation Flashcards
The pulmonary artery is thinner (almost 1/3) than the aorta. Why is this advantageous?
The thin wall of the pulmonary artery allows for greater arterial compliance. Therefore, the pulmonary arteries act to accommodate the output of the right ventricle.
The lung has two circulatory routes, one of high pressure/low flow, and one of low pressure/high flow.
Which one is responsible for supplying the alveoli?
Low pressure, high flow
The pulmonary artery systolic pressure is closest to which of the following?
A. 9 mmHg
B. 15 mmHg
C. 25 mmHg
D. 40 mmHg
C. 25 mmHg
The pulmonary artery diastolic pressure is closest to which of the following?
A. 9 mmHg
B. 15 mmHg
C. 25 mmHg
D. 40 mmHg
A. 9 mmHg
The mean pulmonary artery pressure is closest to which of the following?
A. 9 mmHg
B. 15 mmHg
C. 25 mmHg
D. 40 mmHg
B. 15 mmHg
The left atrial pressure is closest to which of the following?
A. 9 mmHg
B. 15 mmHg
C. 25 mmHg
D. 40 mmHg
A. 9 mmHg
Describe how one obtains the pulmonary wedge pressure
Steps:
1) insert catheter f/ peripheral v. to the right atrium
2) continue insertion through the right heart through the pulm. a. into a small branch of the pulmonary a.
3) continue insertion until the catheter wedges into a small branch of the pulmonary artery
“The blood flow has been stopped in the small wedged artery.”
Failure of the right heart can lead to build up of stagnant blood in the pulmonary circulation, T/F
False. Left sided heart failure produces pulmonary problems
When blood in the left atrium is measured, it contains less oxygen than is expected. This is due to:
a. COPD, a disease that prevents the diffusion of O2/CO2 at the alveoli
b. Mixing of deoxygenated blood that has been dumped into the pulmonary vein after delivering O2 to the lung parenchyma
c. Bypassing of blood around the pulmonary artery and through the descending abdominal aorta
b. Mixing of deoxygenated blood that has been dumped into the pulmonary vein after delivering O2 to the lung parenchyma
Physiologic shunt supplies oxygen to the lung parenchyma itself
Decreased alveolar PO2 regulates pulmonary blood flow. It is believed to be due to oxygen sensitive potassium channels closing, which produces (by calcium influx) vasoconstriction in the poorly perfused alveolar capillaries.
Below what PO2 does this occur?
A. 90%
B. 80%
C. 70%
D. 60%
C. 70%
Unless experiencing a pathological condition, this zone receives no blood flow, as capillary pressure is less that alveolar pressure.
A. Zone 3
B. Zone 2
C. Zone 1
C. Zone 1
This region of lung tissue receives blood only during systole (P capillary > P alveoli).
Zone 2
The lung apices normally have zone ____ blood flow.
A. 3
B. 2
C. 1
B. 2
Continuous blood flow is found in zone ____.
3
Lower lung regions have zone ____ flow.
A. 3
B. 2
C. 1
A. 3
The pulmonary veins can release up to ____ mL of blood upon an individual standing.
400
Dilation of ____ in a lung occurs when blood flow to the other lung is ceased.
pulmonary vessels
Dilation of pulmonary arterioles occurs with every drug but:
A. isoproteronol
B. Angiotensin II
C. Acetylcholine
B. Angiotensin II
Constriction of pulmonary arterioles occurs with every drug except:
A. Norepinephrine
B. Acetycholine
C. Prostaglandins
D. Epinephrine
B. acetylcholine
Serotonin, histamine, and e. coli endotoxin all act to constrict pulmonary (arterioles/venules)
venules
Pulmonary arterial pressure rises very little during exercise. Why is this so?
A. Increased blood flow opens capillaries
B. Increased blood flow distends capillaries
C. Both A and B are correct
D. Blood flow is shunted to major muscle groups being used in exercise
C. A & B are correct
Though pulmonary arterial pressure is increased some, the distention and opening of capillaries in the lungs causes a larger volume of vessel for the blood to occupy.
Think of distensibility: P/V; in exercise, the volume is increased, though the opened vessels allow for more area for that volume to occupy, thereby keeping pressure changes minimal.
In left heart failure, the pressure in the left atrium can rise from 1-5 mmHg to up to _____ mmHg.
50 mmHg
Increases of left atrial pressure greater than ____ produces equal changes to pulmonary arterial pressure.
A. 2 mmHg
B. 5 mmHg
C. 8 mmHg
D. 10 mmHg
C. 8 mmHg
What are the three most common causes of pulmonary edema?
1) Left sided heart/mitral valve disease
2) Damage to pulmonary capillary membranes by infection
3) Damage to pulmonary capillary membranes by noxious substances (ex: phosgene gas)
Edema of the pleural cavity is known as ____.
pleural effusion
Pumping of fluid from the pleural space usually results in a pleural pressure of _____.
-7 mmHg
Lowered PO2 in poorly ventilated alveoli produces (vasodilation/vasoconstriction)
Vasoconstriction (Prostaglandin mediated)
pH drops due to increased PCO2, which produces vasoconstriction. This is OPPOSITE of the changes induced by increased PCO2 in other tissues
The lung has two circulatory routes, one of high pressure/low flow, and one of low pressure/high flow.
Which one is responsible for supplying the CT/trachea/bronchial tree/lung parenchyma
High pressure, low flow.
