Pulmonary Blood Flow

Question 0

What physiological factors induce pulmonary vessel pressure drop?

Answer 0

Recruitment of more capillaries
Distention of capillaries to allow more flow
Expansion of the lung

Question 1

What are some disease states that change the pressures of pulmonary capillaries?

Answer 1

CHF, mitral stenosis

Question 2

What drugs induce pulmonary vessel pressure decrease?

Answer 2

Acetylcholine, isoproterenol, prostacyclin

Question 3

What physiological influences cause increase in pulmonary vessel pressure?

Answer 3

Alveolar pressure increase

Hypoxia induced vasoconstriction

Question 4

What chemicals promote vasoconstriction in pulmonary vessels?

Answer 4

Histamine, Norepinephrine, serotonin

Question 5

Which COX product inhibits platelet aggregation?

Answer 5

Prostacyclin

Question 6

What is the extremly undesirable side effect of selective COX2 inhibitors?

Answer 6

Hypercoagulability from decreased prostacyclin synthesis, resulting in higher risk for MI

Question 7

How can you calculate pulmonary blood flow with only knowing the oxygen concentrations in veins and arteries as well as consumption rate?

Answer 7

Fick principle

Q=VO2/([O2]a-[O2]v)

Question 8

What does zone one represent in terms of pulmonary blood flow distribution?

Answer 8

PA>Pa>Pv, means that alveolar pressure is collapsing both veins and arteries in the area

Question 9

What does zone 2 represent in the pulmonary blood flow distribution?

Answer 9

Pa>PA>Pv

Means that the flow is determined by pressure difference between alveoli and arteries.

Question 10

What does zone 3 represent in the pulmonary blood flow distribution?

Answer 10

Pa>Pv>PA

Normal situation in circulatory system, means that flow is determined by arterial and venous pressure differential

Question 11

What would cause zone 1 to be present?

Answer 11

Not naturally present, only in disease states like hemorrhage or positive pressure breathing
Becomes physiological dead space

Question 12

Where is zone 2 most representative?

Answer 12

Apical regions of the lung

Question 13

Where is zone 3 representative of in the lung?

Answer 13

Midregions or base

Question 14

What mechanism is thought to take place in hypoxia-induced vasoconstriction?

Answer 14

Closure of voltage gated K channels

leading to intracellular [Ca] increase

Question 15

What would closure of VG K channels do to the membrane potential?

Answer 15

Hyperpolarize

Question 16

What controls fluid movement in and out of the pulmonary vasculature?

Answer 16

Starling forces (Osmotic pressure and oncotic pressure)

Question 17

Why must there be some flow out of the capillaries?

Answer 17

Lymph drainage is needed

Question 18

What is the function of the lungs when we lie down?

Answer 18

They become a reservoir of blood as the blood goes from legs to lungs

Question 19

How do lungs prevent stroke?

Answer 19

Venous emboli from legs cannot go to brain because they must first go through pulmonary bed

Question 20

What are some metabolic responsibilities of the lung relating to ACE?

Answer 20

Converting ATI to ATII through ACE

Inactivating Bradykinin through ACE

Question 21

What are the lungs’ responsibilities when it comes to serotonin?

Answer 21

Remove from system through accumulating it

Question 22

What is the role of the lungs when it comes to PG and LT?

Answer 22

Metabolizes PGE1, PGE2, PGF2alpha
Synthesizes prostaglandins as well as some leukotrienes (bronchoconstrictors)
Removes some leukotrienes from systemic circ

Question 23

What makes the lungs less likely to experience edema than any other circulation?

Answer 23

Low hydrostatic pressure