Pulmonary Circulation Flashcards
Is pulmonary circulation compliant?
Highly so
What does the pulmonary circulation contain?
Fibrinolytic system
What does the pulmonary circulation also function as?
Blood reserve
Renin-angiotensin system
How many bronchial arteries do we have?
2 for left lung
1 for right lung
What do bronchial arteries deliver blood to?
Connective supportive tissue
Septa
Bronchioles
Large blood vessels
What is lung perfusion?
Amount of blood flow to the alveoli
What is the systolic pressure through the pulmonary circulation?
25mmHg
What vessels are associated with respiratory bronchioles?
Intra-acinar vessels
Are pulmonary or systemic arteries more compliant?
Pulmonary
What is necessary for gas exchange?
Ventilation and perfusion
What occurs when there is perfusion without ventilation?
Physiological shunt
What occurs when there is ventilation without perfusion?
Physiological deadspace
Where is the greatest pressure in the lung?
The more superior part
When is the pulmonary vascular bed not perfused?
Resting cardiac output
What happens between the pulmonary and systemic circulations when an individual changes from a supine to erect position?
Around 400ml of blood is transferred to systemic circulation
Where do bronchial veins drain to?
Right side of the heart
Where do bronchopulmonary veins drain to?
Left side of the heart
What is the pressure gradient driving flow through pulmonary circulation in mmHg?
7mmHg
What intrinsic tendency do pulmonary veins have?
To collapse
How are veins opened in pulmonary circulation?
Pulled open by traction by parenchyma
What happens to pulmonary capillaries when the lung inflates?
Diameter of capillaries decrease
Where are extra-alveolar vessels found?
Tethered to parenchyma
What name is given to blood flow in pulmonary capillaries?
Sheet action
What is the diameter of the capillaries and their blood flow dependent on?
The relationship between blood pressure and alveolar pressure
Why is there lower resistance in pulmonary arteries than systemic ones?
Vessels have relaxed smooth muscle
When blood flow increases, resistance decreases
Influence of lung expansion
When is there increased resistance in pulmonary vessels?
At both high and low volumes
When is there the least resistance in pulmonary vessels?
At the point of FRC
What is the flux of fluid determined by?
Capillary hydrostatic
Tissue hydrostatic
Capillary oncotic
Tissue oncotic pressures
What in pulmonary oedema?
Build up of water in interstitium/alveolus
What does pulmonary oedema ultimately result in?
No gas exchange
What does a fibrinolytic system do?
Remove clotting factors
