Lec 22 Flashcards
During ventricular ejection, blood presuure
will cause arteries to stretch and expand and store pressure in elastic walls
During isovolumc ventricular relaxation, how blood goes forward
the pressure that was stored in elastic walls, will recoil to maintain pressure
blood presuure measured in
arteries
pulse pressure
systolic pressure - diastolic pressure
mean arterial pressure formula
Diastolic pressure + 1/3 (pulse pressure)
why MAP formula is like that
as bloood spend less time in systolic than diastolic
MAP calculation in 120/80 BP
80 +1/3(120-80)=80+13.3=93.3
MAP illustrates
Mass balance
what do we mean by mass balance
what comes in, should go out
MAP minimum
60
two main ways bp is regulated
1- fluid loss/retention of kidneys
2- arterial tone -> vasodilation/vasoconstriction
four elements acting on MAP
1- Blood vloume
2- CArdiac output
3- resistance of system
4- relative distribution of blood (mass balance)
if MAP increase what have happened to four major elements
1- blood vol. increase (higher intake/lower loss)
2- cardiac output increases
3- resistance increase
4- diameter of veins decrease
cardiac output increase by (2 factors)
1- higher HR – dual input sym/parasym
2- Higher SV – contractility only by sympathetic
higher resistance is due to
lower diameter of arterioles
lower diameter of veins is leads to (4step in order)
1- higher venous constriction
2- higher venous return
3- higher sv
4- higher MAp
two systems acting in response of increase in BV/Bp
1- cardiovascular
2- renal system
response to high BV is —- feedback
negative
high BV triggers two different response
1- fast response (sec-min)
2- slow response (hour-days)
slow response to BP
compensation by kidneys (excretion of fluid in urine
fast response to high bp
compensation by cardiovascular system
1- vasodilation
2- lower CO
arteriole resistance formula
Ln/r^4 (n is viscosity)
in resistance formula — and — is not changing
length and viscosity
radius can be changed by changes in
vascular smooth muscle
