Flashcards in Lecture 10 Arterial and Venous Systems and Lymphatics Deck (55)
What is the equation for Vascular Distensibility?
Vascular distensibility = Increase in volume/(increase in pressure x Original Pressure)
Which of the following factors affect(s) pulse pressure?
a. Vascular Elastance
b. Arterial Compliance
c. Stroke Volume
d. all of the above
c. B and C only
c. B and C only
Which of the following is the most important means for the exchange of substances between the blood and the interstitial fluid?
a. Blood hydrostatic pressure
b. Capillary oncotic pressure
d. Interstitial fluid hydrostatic pressure
The least amount of damping of the pressure pulses would occur in which of the following components of the circulatory system?
a. Femoral Artery
a. Femoral Artery
Distensibility in Arteries vs. Veins
Veins are about 8 times more distensible than arteries
Distensibility in pulmonary veins vs. systemic veins
Distensibilities are about the same
Distensibility in pulmonary arteries vs. systemic arteries
Pulmonary artery distensibilities are about 6 times that of systemic arteries
What describes the distensibility of BVs?
Capacitance is _______ (Directly/Indirectly) proportional to elastance
Compliance is equal to ?
Distensibility x Volume
Capacitance is ______ proportional to volume and ______ proportional to pressure
What does capacitance describe?
It describes how volume changes in response to a change in pressure
Where is capacitance the greatest? Veins or arteries?
The greater the amount of elastic tissue in a blood vessel:
The higher the elastance
The lower the compliance
Measure of the ease with which a hollow viscus may be distended
The volume change resulting from the application of a unit pressure differential between the inside and outside of the viscus;
Compliance is the ______ of elastance
Total quantity of blood that can be stored in a given portion of the circulatory system
What is elastance a measure of?
Measure of the tendency of a hollow viscus to recoil toward its original dimensions upon removal of a distending or collapsing force
Describe the Volume Pressure curves for both arterial and venous systems
In the arterial system, volume does not have to change much to affect the pressure.
In the venous system, a large change in volume can have little affect on the pressure
What is Pulse Pressure?
Difference in systolic and diastolic pressure
Stroke Volume/Arterial Compliance
What factors affect pulse pressure?
Stroke volume output of the heart
Compliance of the arterial tree
Describe how stroke volume output affects pulse pressure
Most important determinant of pulse pressure
Diastolic pressure remains unchanged during ventricular systole; pulse pressure increases to the same extent as the systolic pressure
Describe how compliance of the arterial tree affects pulse pressure
Decrease in compliance (capacitance) results in an increase in pulse pressure
Name conditions causing abnormal contours of the pressure pulse wave
Aortic Valve stenosis
Patent ductus arteriosus
Describe how aortic valve stenosis affects pulse pressure wave
Diameter of the aortic valve opening is reduced sig., & aortic pressure is decreased sig.
Blood flow through aortic valve is diminished
Describe how patent ductus arteriosus affects pulse pressure wave
Half or more of cardiac output flows back into pulmonary artery & lung BVs
Diastolic pressure falls very low before next heartbeat
Describe how aortic regurgitation affects pulse pressure wave
Aortic valve is absent or will not close completely
Aortic pressure may fall all the way to 0 between heartbeats
Why is the mean blood pressure closer to the diastolic than the systolic?
Because about 60% of the cardiac cycle is spent in diastole and 40% in systole
Define mean arterial pressure
Average arterial pressure with respect to time
*B/c more of the cardiac cycle is pent in diastole than in systole, it is NOT a simple average