Arterial Vessels & Haemodynamics

cgeorge's version from 2016-02-24 14:16


Question Answer
Aorta ... this pulsatile pressure to ensure ....Dampens .. Continous flow into the circulation
Equation for mean ABP (SP-DP)/3 + DP
Equation for pulse pressureSP - DP
Systolic pressure = 120mmHg
Diastolic pressure = 80mmHg
What happens to walls of the aorta during systoleDistends
What happens to walls of the aorta during diastoleRecoils
Which vessels have the biggest resistanceArterioles
3 factors that determine resistance to blood flow Vessel length, blood viscosity and radius
Can change blood viscosity byIncreasing number of RBC's
Main determinant of flow isArterial pressure
Describe turbulent and laminar flowTurbulent = Occurs when flow speed is high, you can hear this type of flow whereas you cant hear laminar flow
Area of the normal aortic valve4cm2
What is stenosisHardening of aortic valve, reduced area of the aortic valve, so in order to maintain flow the speed of blood has to be trebled to 170cm/s
2 determinants of arterial blood pressure1) Blood volume in the arterial system (CO). 2) Resistance to blood flow (TPR)
What happens to your aortic compliance as you ageDecreases, so decreased blood pressure
4 determinants of SP1) Stroke volume 2) Aortic distensibility 3) Ejection velocity 4) DP of previous beat
2 determinants of DP1) Arteriolar resistance 2) Heart rate ( has to be litro at max heart rate to effect DP)
What happens to SP and DP as you age?Increased SP, lower DP. So pulse pressure increases with age (Pulse pressure = SP - DP)
What do endothelial cells secrete and what effect does this have?Vasoactive substances that cause smooth muscle to relax/contract
Name a vasoactive substance secreted by endothelial cells and its effectNO - Main vasodilator
Describe the myogenic reflexIf pressure in vessel drops, causes relaxation and vasodilation
Increasing sympathetic stimulation will cause vasoconstriction or vasodilation?Vasoconstriction
a1 receptors are found on predominantly ... and vasoconstrict when ... is released via ... Skeletal muscle, Noradrenaline, Increased SNS
b2 receptors are found on ... and vasodilate when ... binds from ... Skeletal muscle, Noradrenaline, Increased SNS (but it binds VERY weakly)
Adrenaline released binds to which receptors on skeletal muscle to cause vasodilationB2
Adrenaline can bind very weakly to which receptors to cause vasoconstrictionA1
Does ADH cause vasoconstriction or dilationVasoconstriction
Angiotensin II causes vasoconstriction or dilation?Vasoconstrictio