Blood Flow and Metabolism in Pulmonary Circulation Flashcards
From pulmonary veins to the capillaries, what happens to diameter?
Diameter decreases
When deoxygenated blood circulates throughout the lung vasculature to be oxygenated its called:
pulmonary perfusion
An increase in resistance can lead to_____________________
Pulmonary hypertension
What is are the short segments of capillaries on alveoli called?
Net capillary bed
Describe pressure in the pulmonary circulation vs systemic circulation
Low pressured system
What is the purpose of pulmonary circulation?
Gas exchange
What is stretched on inhalation and pulls the arteries/veins to keep them open inside the alveoli?
Parenchyma
If the TV increases what happens to gas exchange?
Decreases
Why are capillary walls exposed to outside alveolar pressure?
Alveolar air
Pulmonary Vascular resistance =
(input pressure - output pressure) / blood flow
Why is vascular resistance always low?
To allow for exchange to happen
What is the mean pressure in the pulmonary artery?
15 mmHg
Mean pressure in a systemic artery is ?
100 mmHg
When capillaries open in a higher pressure it is termed:
Recruitment
Define distension
Widening of capillaries as pressure increases
Recruitment and distension are the main mechanisms to decrease what?
Vascular resistance
Why is the Fick principle clinically relevant?
To assess lung function in respiratory distress
How can you measure blood flow (Q)?
Q = VO2 / [Arterial O2] - [venous O2]
In supine animals, describe blood flow in the lungs?
More uniform
List the zones of the lungs
Zone 1, 2, 3
Around how much is the pressure difference between top and bottom of the lungs?
23mmHg
Alveolar pressure is greater than pulmonary artery pressure in which zone?
Zone 1
Which lung zone is the ideal diffusion zone for gases?
Zone 2
Describe pressure in Zone 3
Artery > Venous > Alveoli
T/F Blood flow increases along acinus
True
How does active control of circulation dictate distribution?
Direct blood flow from a diseased lung
Low O2 in alveoli will lead to a constriction and divert blood from poorly ventilated areas. this is known as:
Hypoxic Pulmonary Vasoconstriction (HPV)
What happens at birth to dramatically increase pulmonary blood flow?
Release of HPV
HPV directs blood
a- toward hypoxic area
b- away from hypoxic area
b
Describe water balance in the lung
Capillary pressure around themselves keep water away (Starling’s Law)
What can happen when water balance fails?
Pulmonary edema
Where is interstitial edema found?
Perivascular spaces
Lung as a metabolic organ can modify vasoactive substances. Give an example of one
Angiotensin
serotonin
ACE is a vasodilator or constrictor?
Constrictor
What 2 substances are associated with arachidonic acid metabolism?
PGs and Leukotrienes
Alveolar edema impairs:
a - gas exchange
b - blood filtration
c - lymph flow
A
