Lecture 15: Hemodynamics and Systemic Circulation Flashcards
(24 cards)
Which vasculature has the highest and lowest pressure?
Highest pressure: arteries
Lowest pressure: veins
Which vasculature has the highest amount of volume for blood?
Veins (65% total blood volume)
When veins constrict, what happens to the blood?
Can move blood to arterial side to increase blood pressure
*change in volume but not with resistance
When arteries constrict, what happens to the blood?
There is a change in resistance but not much with volume
How do you calculate the velocity of blood flow?
Velocity = Flow/Area
How do you calculate blood flow?
Flow = Pressure Gradient/Resistance
How do you calculate cardiac output?
Cardiac Output = (Arterial - Venous Pressure)/Total Peripheral Resistance
What factors can affect resistance?
Viscosity
Length of Vessel
Radius of Vessel (biggest factor)
Adding resistance beds in series _____ resistance
Adding resistance beds in series INCREASES resistance
Adding resistance beds in parallel _____ resistance
Adding resistance beds in parallel DECREASES resistance
What is laminar flow?
Smooth blood flow with little turbulence
<2000
What is the Reynolds number equation?
Reynolds Number = (density x diameter x velocity)/Viscosity
*Becomes more turbulent is there is an increase in density, diameter, velocity or decrease in viscosity
What is compliance?
How easy for vessel to expand
What is the formulate to calculate compliance?
Compliance = (Δvolume)/(Δ pressure)
Which type of blood vessel has the greatest compliance?
Veins
When veins constrict, what happens to its compliance?
Volume is reduced so compliance decreases
- blood shifts to arterial side, increasing arterial blood pressure
- can change diameter and compliance stays the same
Why is there a pulsatile nature in the blood pressure from aorta to small arteries?
Due to compliance and distension during ejection and recoil during diastole
How do you calculate pulse pressure?
Pulse Pressure = Systolic - Diastolic
How do you calculate mean pressure?
Mean Pressure = Diastolic + ⅓ Pulse Pressure
Why is blood pressure so low in the lungs?
Very little resistance
If there is a decrease in compliance, what would happen to pulse pressure?
It will increase
*think about compliance formula
If there is a increase in resistance, what would happen to pulse pressure?
Stays the same
-if cardiac output and stroke volume stays the same
How is left atrial pressure measured?
Why?
Use a catheter through jugular vein –> RA –> RV –> pulmonary vein and blow up a balloon
- pressure measured here is related to Left Atrium pressure
- good sign of cardiac failure
What is cardiac failure?
Left ventricle cannot properly pump blood efficiently
