Exam 1 Circulation

Question 1

What is the equation for blood flow? What is the equation for Ohm’s Law?

Answer 1

F = (difference in P at the two ends of the vessel) / (vascular resistance aka impediment of flow)

Ohm’s Law: V = IF

Question 2

What is the equation for conductance in regards to resistance?
What is the formula for Poiseuille’s Law? ( what is this law derived from measuring?)

Answer 2

Conductance = 1 / Resistance

Poiseuille’s Law aka fourth power law:

F = (pi x change in P x r^4) / (8 x viscosity x length of vessel).
It is derived from measuring the velocities of the concentric rings of the vessel.

Question 3

What is the equation for the conductance of a parallel pathway?
What is the equation for total resistance of a parallel series?
What is the equation for total resistance of a constituent vessel in a series?

Answer 3

C total = C1 + C2 + C3…

1/R total of a series = 1/R1 + 1/ R2 + 1/R3…

Rtotal = R1 + R2 + R3…

Question 4

What is the formula for vascular distensibility?

What is the formula for vascular compliance?

Answer 4

Vascular distensibility = (increase in volume) / (increase in pressure x the original volume).

Vascular compliance = (increase in volume) / (increase in pressure).

Question 5

What is the equation to measure dampening of the pressure pulse?

Answer 5

Dampening = resistance x compliance

Question 6

Equations for Net filtration pressure of capillaries and filtration.

Answer 6

NFP = Pc - Pif - plasma colloid osmotic pressure + intestinal fluid colloid osmotic pressure.

Filtration = Kf x NFP where Kf = the filtration coefficient.

Question 7

Mean capillary pressure equation?

Answer 7

Mean capillary pressure = Arterial pressure - venous pressure

Question 8

What is formula for venous return?

Answer 8

VR = Psf - RAP / RVR.

Where Psf = mean system filling pressure, RAP = right arterial pressure, and RVR = resistance to venous return.