Distribution of Pulmonary Blood Flow Flashcards
Contributory factors of linear distribution of pulmonary blood flow.
Gravity
Cardiac output
Pulmonary vascular resistance
The amount of blood the heart pumps in 1 minute.
Cardiac Output
Determinants of cardiac out put are:
Heart Rate
Stroke Volume
Number of times the heart beat in a minute.
Heart rate
A higher heart rate, increases cardiac output as it multiplies by stroke volume.
True
An excessively high heart rate decreases cardiac output.
True
The volume of blood pumped out of the ventricle of the heart during each systolic cardiac.
Stroke Volume
Stroke volume is determined by the following factor.
Ventricular preload
Ventricular afterload
Myocardial contractility
The stretch of myocardium or end-diastolic volume of the ventricles and most frequently refers to the volume in a ventricle just before the start of systole.
Ventricular preload
The higher the ventricular preload, the greater the heart muscle will contract during systole.
True
The amount of resistance the heart must overcome to open the valves and push the blood volume out into the circulation.
VENTRICULAR AFTERLOAD
Force of the contraction of the heart muscle.
MYOCARDIAL CONTRACTILITY
The more forceful the contraction is the more blood it
ejects.
TRUE
Increase in myocardial
contractility
Positive inotropism
Decrease in myocardial
contractility.
Negative inotropism
The resistance in the pulmonary vascular bed against which the right ventricle must eject blood.
Pulmonary Vascular Resistance
If the pressure in the pulmonary vasculature is high, the right ventricle must work harder to move the blood forward past the pulmonic valve
True
In this zone, the venous pressure exceeds alveolar pressure.
Zone 3
lood flow increases as one moves vertically down this zone due to the progressive distention from the increasing intraluminal pressure (intravascular pressure increasing down
the zone while alveolar pressure is constant).
True
The blood flow is determined by the difference between arterial and alveolar pressures, rather than by the expected arterial-venous pressure difference
Zone 2
Least gravity dependent area.
Preventing blood flow in this region.
Zone 1
Alveolar pressure is sometimes greater than both arterial and venous
intraluminal pressure
True
Said to exist ( it is when alveoli is
ventilated, but not perfused, hence gas exchange doesn’t occur.
Alveolar dead space
Exerted pressure between base and apex is 22 mm
Hg, therefore the pulmonary artery pressure
supplying the apex must be > 11 mm Hg.
True
The intraluminal pressures of the lower lung region
is greater than the upper lung region.
True
High intraluminal pressure causes the vessels to
widen.
True
