Pulmonary Circulation

Question 1

Conducting and respiratory blood uspply

Answer 1

Conducting - bronchial

Respiratory - pulmonary circulation

Question 2

BPs in pulmonary circulation and the path

Answer 2

Venous blood in the right side of the heart…into pulmonary arterty…passes through pulm capillary into pulmonary vein and then into left atrium and ventricle

Pressure is much higher in the LV and aorta

Question 3

Anatomic featurs of pulmonary circulation

Answer 3

Sheet flow (extremely large circulation)

Provide nutrient supplies to lung parenchyma and respiratory bronchioles

In series with systemic circulation…low pressure and low vascular resistance

Question 4

Major functions of pulmonary circulation

Answer 4

Gas exchange
FIltering function
Metabolic function

Question 5

Anatomic features of bronchial circulation

And major function

Answer 5

Bronchial artery is branch of systemic circulation

Blood in bronchial artery is high O2 and low CO2 (vs. pulmonary artery which is high CO@ and low O2)

Nutrients and O2 to conducting airways

Question 6

Pulm vs. bronchial

Structures supplied and blood flow

Answer 6

Pulm - respiratory zone, 100% of cardiac output

Bronchial - conducting and <1% of cardiac output

Question 7

Arterial and venous BP and resistance of pulm vs. bronchial

Answer 7

Pulm - 15, 5 , low

Bronchial - 100, 0, high

Question 8

Distribution of pulmonary blood flow

Answer 8

Zone 1 (top) - Pa>Ppa>Ppv

Zone 2 - Ppa>PA>Ppv

Zone 3 - Ppa>Ppv>PA

THink about alveolar pressure pushing on the pulmonary artery and vein

Pulmonary arterial pressure will be greatest on the bottom due to hydrostatic pressure

Most blood flow in zone 3 as you move down from zone 2

None in zone 1

Question 9

Blood flow porportuonal in zone 2 and 3

Answer 9

2 - Ppa - PA

3 - Ppa- Ppv (because the PA is lowest pressure)

Question 10

Hypoxia effect on pulmonary vascular resistance

Answer 10

Pulmonary vasoconstriction and pulmonary HTN

Question 11

Regional vs. generalized hypoxia

Answer 11

Regional - vasoconstriction will shift blood flow to other regions of lung and thereby improve efficiency of gas exchange

Generalized - will lead to pulmonary HTN which can eliminate zone 1 and improve diffusion capaicty…because pulmonary arterial pressure increases

Question 12

Mechs of pulmonary vasoconstriction induced by alveolar hypoia

Answer 12

Inhibitory effect of hypoxia on V-gated K channels and the subsequent membrnae depolarization leading to an increase in clacium concentration in cytopalsm of vascular smooth muscles

Question 13

Neural factors and humoral factors on pulmonary vascular resistance

Answer 13

alpha adrenoreceptors induce vasoconstriction

PS stimulates vasodilation

Some chemicals mediators constrict while some vasodilate

Question 14

Change in lung volume effect on pulmonary vscular rreesistance

Answer 14

Dips at FRC and peaks at both ends (TLC and RV)

At TLC, alveolus is pushing on the alveolar vessels

At RV, the extra-alveolar vessels are constricted…when lung compresses, it compresses those vessels as well

Question 15

Cardiac output and pulmonary vascular resistance

Answer 15

As cardiac output increases, pulmonary vascular resistance decreases

Recruitment - some capillaries are typically collapse (like zone 1)…there as a reserve. They are activated when cardiac output increase when pulmonary arterial pressure increases

Distension - dilation of the pulmonary capillaries allows for more blood flow and less resistance

Question 16

Uptake of things by the lungs

Answer 16

Prostaglandins, leukotrienes, serotonins, bradykinin, angriotensin 1