pulmonary circulation

Question 1

pulmonary vs systemic: wall thickness and lumen

Answer 1

systemic is much thicker (artery and left ventricle) and narrower lumen; pulmonary is more complient so lower blood pressure (shorter distance), preventing pulmonary hypertension

Question 2

pulmonary vs systemic: CO, volume, MAP, MVP, pressure gradient, resistance, relative speed, compliance, ventricular wall thickness

Answer 2

pulmonary: same CO, lower volume (0.5L vs 4.5L, so lower MAP), lower MAP (13 mmHg), higher MVP (most of each volume exists in veins), lower pressure gradient, lower resistance to increase flow, slower, higher compliance, thinner ventricular wall thickness

Question 3

3 functions of pulmonary circulation

Answer 3

gas exchange (CO2 excretion and O2 absorption), metabolism of vasoactive substance (produce angiotensin II and metabolise bradykinin), filtration of blood

Question 4

gas exchange pulmonary transit time

Answer 4

0.75s, with CO2 leaving and O2 entering

Question 5

what do endothelial cell express and why; what does this allow with regard to metabolism of vasoactive substances

Answer 5

express ACE to convert AGTI to AGTII (vasoconstrictor) and break down bradykinin (vasodilator), allowing for vasoconstriction

Question 6

what is caught in the pulmonary vessels and filtered out of the blood before it reaches systemic arteries

Answer 6

emboli (air bubbles, ruptured fatty plaques, venous thrombosis)

Question 7

what happens if the emboli are large

Answer 7

local perfusion obstruction as cannot be broken down

Question 8

define embolus

Answer 8

mass in circulation causing obstruction

Question 9

define embolism

Answer 9

event characterised my major artery obstruction

Question 10

foetal pulmonary circulation pressure and reason

Answer 10

higher due to lungs being filled with amniotic fluid, meaning O2 enters at placenta