Ventilation, Perfusion, Pulmonary Circulation Lecture

Question 1

What is true about pulmonary and systemic ciruculation? (2 things)

Answer 1

1. in series

2. flow rates are the same

Question 2

What is the right to left shunt?

Answer 2

1-2% of blood that goes from right to left heart

Question 3

Why is pulmonary circulation such a low pressure system?

Answer 3

gravity

Question 4

What is hydrostatic pressure? colloid oncotic pressure?

Answer 4

Hydrostatic: tends to push fluid into the tissue (out)

Oncotic pressure: pull fluid into capillaries

Question 5

What happens to a RBC in isotonic solution? once you add water?

Answer 5

isotonic: nothing

add water: swells

Question 6

What is occurring in pulmonary edema?

Answer 6

high hydrostatic pressure goes to intersititium then you get alveolar edema (impaires diffusion of substances)

Question 7

What causes the endothelium of capillaries to become more permeable? (3 things) result?

Answer 7

O2 toxicity, inhaled toxins, infection

pulmonary edema

Question 8

What is the affect on the vasculture at high altitudes?

Answer 8

increases hypoxic pulmonary vasoconstriction: pulmonary edema results

Question 9

What pressure is uniform across the entire lung?

Answer 9

alveolar pressure

Question 10

What is the affect on blood pressure (both arterial/venous) and alveolar pressure in Zone 1 of the lung?

Answer 10

Blood pressure is variable so it is low at top of lung. Alevolar pressure will be greater than arterial which will be greater than venous. Results in collapse of blood vessel in the middle

Question 11

What is the affect on blood pressure and alveolar pressure in Zone 2 of the lung?

Answer 11

Arterial pressure is now larger than alveolar pressure with venous pressure being the smallest. You will collapse at the venous side

Question 12

What is the affect on blood pressure and alveolar pressure in Zone3 of the lung?

Answer 12

Arterial and venous blood are larger than alveolar and thus the vessels will expand and decrease vascular resistance

Question 13

What is the affect of increasing arterial and venous pressures to the pulmonary resistance? Which causes larger effecT/

Answer 13

decreases pulmonary resistance

-arterial

Question 14

What are the two mechanisms for reducing resistance in pulmonary circulation?

Answer 14

dilation: increases diameter
recruitment: small vessels that are normally closed due to low pressure will open when blood pressure increases

Question 15

How does lung volume affect pulmonary vascular resistance?

Answer 15

by poiseulle’s equation

1. at the capillaries, larger volumes means narrowing the diameter thus increasing resistance
2. at large aveolar blood vessels, you stretch out the lung and you are increasing vascular diameter.