Hemodynamics

Question 1

What do veins function as in the circulatory system?

Answer 1

Capacitors

Question 2

What do arteries function as in the circulatory system?

Answer 2

Resistors

Question 3

Is the arteriole curve of pressure and volume elastic or inelastic?

Answer 3

Inelastic

Question 4

Is the venous curve of pressure and volume elastic or inelastic?

Answer 4

Elastic

Question 5

What layers does an artery have?

Answer 5

1. endothelium
2. Elastic tissue
3. Smooth muscle
4. Fibrous tissue

Question 6

What layers do arterioles have?

Answer 6

Endothelium, and smooth muscle layer

Question 7

What layers do capillaries have?

Answer 7

Endothelial layer

Question 8

What layers do venules have?

Answer 8

Endothelium and fibrous tissue

Question 9

What layers do veins have?

Answer 9

1. endothelium
2. Elastic tissue
3. Smooth muscle
4. Fibrous tissue

Question 10

What is the function of the smooth muscle found in arterioles and venules?

Answer 10

Exert tension during active contraction

Question 11

Why is it important for BP to decrease as it enters capillaries?

Answer 11

To prevent tissue damage

Question 12

The rate of blood flow to an organ or tissue is related to what?

Answer 12

The needs of the organ or tissue

Question 13

CO is controlled by what?

Answer 13

The sum of individual tissue needs

Question 14

Arterial pressure regulation is (in/dependent) of local blood flow or cardiac output control?

Answer 14

Independent

Question 15

What are the units of blood flow?

Answer 15

cm^3/sec

Question 16

What are the units of blood velocity?

Answer 16

cm/sec

Question 17

What are the two ways that arterial pressure is controlled?

Answer 17

Nervous reflexes

Hormones

Question 18

What is ohm law for blood flow?

Answer 18

d(pressure) /R = Flow

Question 19

What is Poiseuille’s law for rigid tubes?

Answer 19

Flow = dP(pi)r4 / 8(viscosity)(length)

Question 20

How can you measure viscosity clinically?

Answer 20

taking hematocrit

Question 21

What is anomalous viscosity?

Answer 21

As blood flow decreases, viscosity increases

Question 22

How does blood usually flow? Where is it fastest, and slowest?

Answer 22

In a laminar way (fastest in the inner layer, slowest at the outer layer)

Question 23

What is the effect of laminar flow (what is the shape that it makes)?

Answer 23

Causes a parabolic flow of blood

Question 24

What type of front does turbulent blood flow have?

Answer 24

Squared

Question 25

Why is turbulent flow inefficient?

Answer 25

Have to overcome the resistance to move blood

Question 26

When do you induce turbulent flow?

Answer 26

When listening for Korotkoff sounds

Question 27

Which heart sound is produced from turbulent blood flow?

Answer 27

S4

Question 28

What is Renolds number?

Answer 28

Propensity of fluid to produce a turbulent flow

Question 29

What is the equation for turbulent flow?

Answer 29

Re = 2(radius)(velocity)(ro) / (viscosity)

Question 30

How does vessel flow compare to a rigid tube?

Answer 30

Has a exponential curve, as opposed to a linear one

Question 31

How does no SNS stimulation of vessels compare to high SNA stimulation?

Answer 31

No SNS allows for higher flow rates at lower pressures | x^2 curve

Question 32

How does SNS change resistance?

Answer 32

Increases it, which will decrease flow (1/x curve)

Question 33

What is the transmural pressure equation?

Answer 33

Tension = (d pressure)(radius)

Question 34

As vessel radius increases, or blood pressure increases, what happens to wall tension?

Answer 34

increases (Tension = (d pressure)(radius))

Question 35

What is the buffer for changes in wall tension?

Answer 35

Elastic tissue in vessels

Question 36

What happens to the blood flow as it goes through capillaries? Note that flow = (velocity)(CSA).

Answer 36

Flow remains constant. Thus velocity increases if CSA decreases, and vice versa

Question 37

Does the capillary bed have an increase in CSA or decrease relative to arteries? What, then, happens to velocity?

Answer 37

Increased, thus velocity decreases

Question 38

Is blood resistance lower or higher when vessels are run in a series?

Answer 38

Higher (R1 +R2)

Question 39

Is blood resistance lower or higher when vessels are run in parallel?

Answer 39

Lower (1/R1 + 1/R2)

Question 40

Review all the equations

Answer 40

Don't press 5.

Question 41

What is the critical closing pressure?

Answer 41

The point of pressure at which there is infinite resistance