Flashcards in vascular distensibility and functions of arterial venous system ( ch 15) Deck (12):
nature of arteries to allow them to accomodate with different pressures. Veins are 8 times more distensible than arteries
portion of blood that can be stored in a given portion of circulation for each mmHg pressure rise than to know the distensibilities of the individual vessels
when blood fills a vessels it takes a second for the vessel walls to "catch up"
average systolic pressure
120 mm Hg,
average diastolic pressure
80 mm Hg
difference between systolic and diastolic pressures ( ~ 40mm Hg)
what affects pulse pressure?
stroke volume, compliance of arterial tree
aortic valve stenosis
diameter of aortic valve is reduced. Aortic pressure is reduced significantly
1/2 of blood pumped into aorta flows backwards into pulmonary artery/ This allows diastolic pressure to fall.
aortic valve is absent or doesnt work. So blood flows back into the left ventricle. Aortic pressure can fall all the way to zero between beats.
Transmission of pressure pulse
heart comes out of the left ventricle with a lot of inertia and doesnt really move anywhere. The pressure of the proximal aorta overcomes the inertia to move blood.