Biophysics

Question 1

Regional Resistance (General Formula)

Answer 1

dP/CO

“Divide the pressure differential by Cardiac Output”

Question 2

Where is the most TPR found?

Answer 2

Small arteries and Arterioles

Question 3

TPR eqn:

hint follow regional resistance general formula

Answer 3

TRP= (Aortic Pressure-Central Venous Pressure)/CO

Question 4

Pulmonary Vascular Resistance Eqn:

hint follow regional resistance general formula

Answer 4

PVR=(Pul. Arter Pressure- L. Atrial Pressure)/CO

Question 5

What part of our vasculature has the highest velocity and lowest area?

Answer 5

Aorta

Question 6

What part of our vasculature has the lowest velocity and greatest area

Answer 6

Capillaries

Question 7

Flow (Fluids/Continuity Formula)

Answer 7

Flow=Velocity * Area

Question 8

When can the assumption that the flow on both sides is equivalent?

Answer 8

Only when it’s the same tube, therefore, tubes that bridge off into other tubes will not always have the same flow

Question 9

What causes turbulence and what is its outcome?

Answer 9

Caused by: High velocity, obstruction, sudden diameter increase
Outcome: FLOW REDUCTION

Question 10

Reynold’s number predicts laminar vs. turbulent flow; How?

Answer 10

smaller than 2000 means laminar flow.
Re=rDv/n

Takes into account density, Diameter, Velocity, and Viscosity. High viscosity=laminar

Question 11

Tension formula:

Answer 11

T=P*r

Tension= Transmural Pressure*radius

Question 12

Poiseuiile’s Law

Answer 12

Q=pi*(dP)r^4/8nL

• Bigger radius and bigger pressure differential greatly increases flow
• Length and viscosity slows the flow down

Question 13

Flow “Q” with two pressures setting up a gradient

Answer 13

(P1-P2)/r

Question 14

How do you deal with series vs parallel resistances?

Answer 14

• Add the series, inverse add the parallel.

- Adding another parallel route LOWERS the total resistance