3B Hemodynamics

Question 1

What 3 places receive 75% of the arterial blood flow go from the heart?

Answer 1

1.Renal (25%) 2.GastroIntestinal (25%) 3. Skeletal Muscle (25%)

Question 2

What are the two major variables for measuring blood flow? What is the equation relating all of the variables?

Answer 2

Pressure and Resistance….Blood Flow (Q)=Change in Pressure/Resistance

Question 3

What is blood pressure?

Answer 3

The FORCE with which blood is PUSHED against the walls of the blood vessels

Question 4

What is systolic pressure?

Answer 4

the HIGHEST amount of pressure reached DURING ventricular ejection of blood

Question 5

What is diastolic pressure?

Answer 5

the MINIMUM amount of pressure just BEFORE ventricular ejection begins

Question 6

What is the name of the sounds when measuring BP? When is systolic BP measured? Diastolic?

Answer 6

Korotkoff sounds.. First sound is systolic…NO sound is diastolic

Question 7

What devices use an electronic pressure sensor with a numerical readout of blood pressure?

Answer 7

Oscillometric devices

Question 8

What are the two formulas for MAP?

Answer 8

MAP=2/3DP+1/3SP…..OR…..MAP=DP+1/3PP (PP=SP-DP)

Question 9

What are the 3 sources for resistance within a SINGLE vessel but can accumulate to alter TPR (total peripheral resistance)? WHICH source does NOT change in vivo?

Answer 9

1.Blood Viscosity 2.Vessel Length 3.Vessel diameter/radius….2.Vessel Length is the only one that does not change in vivo

Question 10

Which law is the relationship between resistance, viscosity, vessel length, and vessel radius? What is the formula relating these variables?

Answer 10

Poiseuille’s Law….R=8 V L / pi r^4

Question 11

Anemia: Viscosity? Vascular Resistance? Blood Flow?

Answer 11

Anemia: low viscosity, low vascular resistance, high blood flow

Question 12

PolyCythEmia: Viscosity? Vascular Resistance? Blood Flow?

Answer 12

Increased viscosity, Increased Vascular resistance, Decreased blood flow

Question 13

What is a stack of RBCs? What is the result?

Answer 13

Rouleaux stacks…Ischemia

Question 14

What does a 2 fold increase in vessel radius do to blood flow?

Answer 14

Increases 16 fold!

Question 15

What does a 4 fold increase in vessel radius do to blood flow?

Answer 15

Increases 256 fold!!!

Question 16

What happens to ARTERIAL blood flow when vasoconstriction takes place?

Answer 16

Blood flow DECREASES (Q=P/R…R increases MORE then pressure)

Question 17

What happens to VENOUS blood flow when vasoconstriction occurs?

Answer 17

Venous return INCREASES (Q=P/R…P increases MORE then resistance) (has to do with normally low p in veins and it makes a BIG effect with a little constriction…arteries already deal with high pressure so constriction contributes more there)