Pulmonary Circulation Flashcards
Function of broncial circulation
- protects lung from infarction
- can “grow into” areas of diseased lung (intercostal arteries
Consequences of bronchial circulation
- usual source of hemopytosis
- much of arterial flow drains into left atrium = shunt
General characteristics of blood flow/circulation as circuit
-R/L sides of heart pump to pulmonary and systemic -capillary beds = source of resistance -driving force ==> voltage = pressure -
Calculating pulmonary vascular resistance
PAP (pulm. artery pressure) - LAP (left atrial pressure) = CO * PVR (pulmonary vascular resistance)
Steps in pulmonary circulation
-arteries -capillary network -veins
Systemic vs. Pulm
-systemic: high resistance vessels, high elastance/low compliance, high pressure system -pulmonary: low resistance, low eslastance/high complaice, low pressure system
Pulmonary artery catheterization
-swan-ganz catheter -flow-directed pulmonary catheter -obstruct small pulmonary artery -make static water colum -measure distal pressures
Cardiopulmonary hemodynamics
[picture/table]
Impact of gravity on pulmonary pressure
-much higher pressure @ base vs. apex -gravity impacts blood pressure but not air pressure -blood flow is intermittent near apex b/c there are points @ which the arterial pressure is lower than alveolar
Physiologic zones of pulmonary blood flow
- Zone 1: PA > Pa > Pv
- PA = alveolar pressure
- Pa = arterial pressure
- Pv = venous pressure
- Zone 2: Pa > PA > PV
- Pa = Pv @ diastole
- Zone 3: Pa > Pv > PA
![](https://s3.amazonaws.com/brainscape-prod/system/cm/094/318/411/a_image_thumb.png?1659423924)
PA > Pa (Zone 1) : no blood flows
-mechanical ventilation -Auto-PEEP (COPD)
Other regulatory mechanisms of pulmonary blood flow
-hypoxic pulmonary vasoconstriction -vasoconstriction @ areas w/alveolar hypoxia -serves to preserve V/Q matching
Pulmonary edema
-originates in capillaries
Major function of pulmonary circulation
- gas exchange
- water and solute balance
major determinants of blood flow distribution in lung
- gravity
- hypoxic vasoconstriction