Resp - Pulmonary Blood Flow

Question 1

pulmonary blood flow qualities

Answer 1

high flow (same as CO)
low P
low R

Question 2

why low R pulmonary BF

Answer 2

arteries shorter, dilated
arterioles thin walled, less SM
more compliant
tons of caps

Question 3

factors that alter pulmonary vascular R

Answer 3

change blood flow
change lung volume
change local [O2]
NOT ANS

Question 4

pulmonary R and perfusion

Answer 4

up CO –> up pulm BF –>. down R
down CO –> down pulm BF –> up R
due to capillary recruitment and distension
(more flow opens more caps and dilates open ones)

Question 5

capillary recruitment/distension benefits

Answer 5

low R
up SA
keep cap P low (avoid edema)

Question 6

pulmonary R and lung V

Answer 6

extra-alveolar vessels (arts, veins) affected by Pip

alveolar vessels (arterioles, caps, venules) affected by PA

R lowest @ FRC, increases @ lower and higher Vs

Question 7

pulm R @ high lung V

Answer 7

Pip more negative
up transmural P
distend extra-alveolar vessels (down R)

Alveolar diameter up
alveolar vessels compressed
(up R)

Question 8

pulm R @ low lung V

Answer 8

Pip more positive
compress extra-alveolar vessels
(up R)

alveolar diameter down
alveolar vessels not compressed
(down R)

Question 9

pulm R and O2 levels

Answer 9

hypoxia in alveoli or hypoxemia in blood –> vasoconstriction
direct effect on SM
independent of agonist or NT
regional and generalized hypoxia

Question 10

pulm R and regional hypoxia

Answer 10

regional: vasoconstriction in specific region of lungs
- cause: bronchial obstruction
- little effect on pulm P
- BF return when hypoxia over

Question 11

pulm R and generalized hypoxia

Answer 11

generalized: throughout lungs
- cause: high altitude, chronic hypoxia (emphysema, asthma)
- cause sig up R and pump P
- can cause pulm hypertension

Question 12

pulm BF and lung regions

Answer 12

BF highest at base
BF lowest at apex
(low P, low R - influenced by G)

Question 13

things affecting pulm BF

Answer 13

lung regions (G)
P diffs (A, a, v)

Question 14

zone 1

Answer 14

@ apex
PA > Pa
pulm caps collapse - no flow
usually small/nonexistent in healthy people
increases alveolar dead space (ventilated, not perfused)

Question 15

when does zone 1 occur

Answer 15

when PA is increased (positive pressure ventilation) or

when Pa is decreased (hemorrhage)

Question 16

zone 2

Answer 16

@ middle 1/3 lung
Pa > PA > Pv
partially collapse downstream since PA > Pv
primary area for distension, recruitment during exercise

Question 17

zone 3

Answer 17

@ bottom 1/3 of lung, base
Pa > Pv > PA
optimal gas exchange
V/Q = 0.8 to 1

Question 18

filtration forces

Answer 18

cap hydrostatic P
interstitial colloid osmotic P
surface tension*

Question 19

reabsorption forces

Answer 19

plasma colloid osmotic P
interstitial hydrostatic P
alveolar P*

Question 20

pulmonary cap net movement

Answer 20

favor filtration

excess fluid removed by extensive lymphatics system

Question 21

pulmonary edema mech

Answer 21

*up cap hydrostatic P (high pulm venous P - LV fail, mitral stenosis)
up cap permeability (infections, O2 toxicity)
down plasma colloid osmotic P (starvation, excess IV fluids)
high ST (loss of surfactant)

Question 22

effects of pulmonary edema

Answer 22

hinder gas exchange (CO2 up, O2 down)
flood small airways (obstruction)
down compliance (up ST, interstitial swelling)
==> increase work to breath

Question 23

significance of cap wedge P

Answer 23

approximates L atrial P and pulmonary cap P

used to titrate diuretics