Lecture 11: Arterial and Venous Systems and Lymphatics Flashcards
What is vascular distensibility?
increase in volume / increase in pressure x original volume
Veins are about ____ times more distensible than arteries
8
Pulmonary vein distensibilities are the _____ as systemic veins
same
Pulmonary artery distensibilities are ________ than systemic arteries
six times greater
What is vascular compliance?
increase of volume / increase in pressure
What does capacitance describe?
distensibility of blood vessels
how volume changes in response to a change in pressure
How do you calculate compliance?
distensibility x volume
capacitance is _______ proportional to volume and ______ proportional to pressure
directly; inversely
Is capacitance greater in arteries or veins?
veins
The greater the elastic tissue in a blood vessel, the
_______ the elastane and ______ the compliance
higher; lower
What is compliance?
measure of the ease with which a hollow viscus may be distended
What is vascular compliance?
total quantity of blood that can be stored in a give portion of the circulatory system
What is pulse pressure?
stroke volume / atrerial compliance
What is the most important determinant of pulse pressure?
stroke volume
Diastolic pressure is ____ during ventricular systole, pulse pressure _____ to the same extent as the systolic pressure
unchanged; increases
Decreases in compliance, result in an _____ in pulse pressure
increase
What is aortic valve stenosis?
diameter of the aortic valve opening is reduced significantly, and the aortic pressure pulse is decreased slightly
blood through aortic valve is diminished
What conditions cause abnormal contours of the pressure pulse wave?
aortic valve stenosis
arteriosclerosis
patent ductus arteriosus
aortic regurgitation
What is patent ductus arteriosus?
half or more of the cardiac output flows back into the pulmonary artery and lung blood vessels
diastolic pressure falls very low before next heartbeat
What is aortic regurgitation?
the aortic valve is absent or will not close completely
aortic pressure may fall all the way to 0 to between heartbeats
Changes in pressure pulse as pulse waves travels toward ____
small vessels
The progressive reduction of the pulsations in the periphery= _______
damping of the pressure pulses
What is mean arterial pressure?
the average arterial pressure with respect to time
What is the mean arterial pressure equation?
diastolic pressure + 1/3 pulse pressure
What is pressure in the right atrium?
central venous pressure
What are the factors the regulate right atrial pressure?
ability of the heart to pump blood out of the right atrium/ ventricle
tendency of blood to flow into the right atrium
factors that increase venous return
increased blood volume
increased peripheral venous pressures due to increased large vessel tone
dilation of arterioles
Small arterioles control ______ to each tissue
blood flow
Are arterioles muscular?
yes, highly
What is vasomotion?
cyclical opening and closing of precapillary sphincter
What are capillary split pores?
intercellular clefts spacing of 6-7 nm
allow for rapid diffusion of water, water soluble ions and small solutes
What forms plasmalemmal vesicles?
cave-ins
What plasmalemmal vesicles do?
play a role in endocytosis and transcytosis
What is the most important factor regulating vasomotion?
concentration of oxygen in the tissues
______ is the most important means for the exchange of substances between the blood and the interstitial fluid
diffusion
Rate of diffusion is ______ proportional to concentration differences of the diffusing substances
directly
What do starling forces do?
determine direction of diffusion not or out of the capillary
Lymph vessels possess _______ valves
one way
Lymph flow reaches maximum when interstitial pressure ______
rises slightly above atmospheric pressure
What are factors that increase lymph flow?
elevated capillary hydrostatic pressure
decreased plasma colloid osmotic pressure
increased interstitial fluid colloid osmotic pressure
increased permeability of capillaries
What is the rate of lymph flow equation?
rate of lymph flow= interstitial fluid pressure x activity of lymphatic pump
