Exam 1 - Lecture 2 Flashcards
When Reynolds number is greater than _____, it means there is what?
2000; turbulent flow
what are the units for Reynolds number?
no units… it is a hypothetical number.
What is reynolds equation? What does each symbol represent?
Re = (VxDxP)/n
V = Velocity
D = Diameter
P = Density
N = Viscosity
What blood vessels are most prone to turbulent flow?
Aorta and large arteries.. closer to the heart, the more at risk.
do we see turbulent flow in the veins?
No, velocity is so low
What’s the difference between viscosity and density?
Viscosity = Thickness
Density = Mass per volume
e.g. water is more dense than oil, but oil has higher viscosity.
3 ways to assess bloodflow? (tools)
Electromagnetic detector that monitors the electric magnetic field of iron that moves with the blood.
Or an ultrasonic flowmeter and has to be implanted/wrapped around a blood vessel
lastly, a laser
How does an A-line monitor blood pressure?
Chamber in tray is a piece of metal that is pushed up and down by the pressure, giving us a blood pressure.
What is the pressure volume loop measuring?
Pressure and volume in left or right ventricle
How does the shape and scale change for left and right ventricle?
The shape will be the same and the volume will be the same, but the pressure will be different.
Phase I of pressure volume loop?
Filling, aka diastole.
Starts when mitral valve opens and ends when it closes.
The volume that the left ventricle fills at in a healthy heart?
50mL
What is the volume leftover after systole? what is it called?
50mL, end-systolic volume or ESV
Most of the filling during phase I is
passive
What is filling DEPENDENT upon?
How much preload we have/pressures entering heart
What is the atrial kick?
Last portion of filling the ventricle gets before it contracts, gets the last 10mL’s of blood into the ventricle to total 120mL’s
How much total blood fills during phase I?
70mL’s
When does the atrial kick become very important?
When heart is sick and doesnt passively fill as much.
In healthy people, its not very important.
In diseases hearts, what % is dependent upon atrial kick
greater than 25%
What does diastole mean?
filling
Phase 2 of pressure volume loop
Contraction, then ventricle pressure is greater than atrial pressure and the mitral valve closes.
What phase are both aortic valve and mitral valve closed?
Phase II and IV
What signals the beginning and end of phase II?
Mitral valve closes is the beginning, the end is when the aortic valve opens.
When is there no change in volume in the ventricle? what is it called?
Phase II and phase IV, called the isovolumetric contraction and isovolumetric relaxation.
When does phase III start?
when aortic valve opens because the ventricle pressure is greater than the aortic pressure.
What is phase III called?
Period of ejection
What is the equation of stroke volume?
difference between volume during isovolumetric contraction (beginning of phase III) and volume during isovolumetric relaxation (end of phase III)