Pulm Circulation

Question 0

Bronchial Circulation

Answer 0

2% output of LV, from thoracic aorta, supplies trachea & bronchial structures, venous blood enters pulm vv that’s been mixed w/ alv. air (R to L shunt)

Question 1

lung receives blood via:

Answer 1

bronchial (from systemic) and pulmonary circulations

Question 2

Pulmonary Circulation

Answer 2

entirely from RV, supplies lungs, gas exchange w/ alv. air in pulm. cap., thin walled, more distensible, less resistance, low P

Question 3

R = (P1-P2)/F

Answer 3

R = resistance, P1 = P at beginning, P2 = P at end, F = flow

Question 4

PVR = (MPAP - MLAP) / PBF

Answer 4

PVR = pulm vascular resistance
MPAP = mean pulm arterial P
MLAP = mean left atrium P
PBF = pulm blood flow

Question 5

pulm vascular resistance distribution

Answer 5

1/3 each in pulm aa, cap., & vv

Question 6

pulm vasculature

Answer 6

high distensibility, low intravascular P, lil’ smooth muscle

Question 7

extravascular effects on PVR

Answer 7

gravity, body position, lung volume, alv./intrapleural P, intravascular P, RV output

Question 8

transmural P = P inside - P outside

Answer 8

Tm P incr., diameter incr., resistance decr.

(-) Tm P: collapsible

Question 9

inspiration

Answer 9

lung V incr., alveoli V incr., intrapleural P more (-)

alv. vessels: incr. R to blood flow
extraalv. vessels: decr. R to blood flow

Question 10

expiration

Answer 10

lung vol. decr, alv. vol. decr., intrapleural P more (+)

extraalv.: incr. resistance to blood flow

Question 11

PVR

Answer 11

alv. & extraalv. vessels in series w/ each other - additive

PVR lowest at FRC, incr. at lower & higher volumes

Question 12

exercise - CO incr. w/o incr. in MPAP - decr. in PVR w/ incr. in blood flow

2 reasons why PVR decr.

Answer 12

recruitment - incr. blood flow opens previously collapsed cap.

perfusion P incr, Tm P incr –> distention - incr. in radii & decr. in resistance

Question 13

w/ recruitment & distention, no incr. in PAP w/ incr. in RV output

what happens otherwise

Answer 13

RV failure from being overworked

incr. fluid filtration –> pulm edema

Question 14

neural effects on pulm vascular smooth muscle

Answer 14

innervations sparse

symp: controversial
parasymp: vasodilation

Question 15

hormoral effects on pulm vascular smooth muscle

Answer 15

catecholamines, E/NE: incr. PVR
histamine, prostaglandins, endothelin, alveolar hypoxia & hypercapnia: pulm vasoconstrictors
acetylcholine, B-adrenergic agonist isoproterenol, nitric oxide, prostaglandins: pulm vasodilators

Question 16

regional distribution of pulm blood flow due to gravity

Answer 16

lower regions of lung: incr. hydrostatic P, incr. distensibility, decr. resistance, incr. blood flow

Question 17

Zone 1, when person is standing

Answer 17

blood flow lowest
Palv > Pa > Pv
Palv can decr. blood flow (Pa decr. from hemorrhage or Palv incr. by positive P ventilation; Zone 1 ventilated & not perfused

Question 18

Zone 2, when person is standing

Answer 18

blood flow is medium

Pa > Palv > Pv

Question 19

Zone 3, when person is standing

Answer 19

blood flow is highest

Pa > Pv > Palv

Question 20

hypoxic vasoconstriction decr. pulm blood flow to possible “wasteful” areas

2 possible mechanisms

Answer 20

Inhibition of:

1) outward K current –> sm. muscle cells depol. –> Ca enters –> contraction
2) NO synthase

Question 21

hypoxic vasoconstriction at high altitude

Answer 21

PAO2 decr. t/o lung, arterioles constrict, PVR incr., PAP incr.

chronic: PAP incr. –> RV hypertrophy

Question 22

hypoxic vasoconstriction in fetal circulation

Answer 22

PAO2 lower in fetus so vasoconstriction: incr. in PVR, decr. blood flow

these all reverse when baby takes its first breath

Question 23

pulmonary edema

Answer 23

impairs gas transfer, builds up first in interstitium, builds up next in alveoli
Starling eq. describes factors influencing movement of fluid
lymphatics as good as any other organ under normal conditions

Question 24

Pulmonary Edema Cause Capillary Permeability

Answer 24

capillary endothelium integrity destroyed by infections or toxins

Question 25

Pulmonary Edema Cause Hydrostatic Pressure

Answer 25

Capillary: incr., filtration incr.; from LV problems, mitral stenosis, too much IV fluids, occlusion of pulm vv Interstitial: decr., incr. edema; from rapid evacuation of chest fluid

Question 26

Pulmonary Edema Cause Colloid Osmotic (or Oncotic) Pressure

Answer 26

Plasma: decr., incr. edema; from hypoproteinemia or too much IV fluids Interstitial: incr. conc. of solute in interstitium

Question 27

Pulmonary Edema Cause 4 others

Answer 27

insufficient lymph drainage head injury heroin overdose high altitude

Question 28

``` Adult Respiratory Distress Syndrome: What is it? When is it seen? What do you see in the lungs? Symptoms? ```

Answer 28

severe lung injury w/ cont. inflammation & incr. cap. permeability seen after inhalation of toxins or infections diffuse alv. damage & pulmonary edema breathlessness; rapid, shallow breathing; dry cough; chest pain