21 Overview of Circulation and Hemodynamics

Question 1

Is blood pressure higher in the arteries or in arterioles?

Answer 1

arteries

Question 2

What vessels exhibit compliance and elasticity in order to reduce pulsatility?

Answer 2

aorta and large arteries

Question 3

What vessels are the major site of vascular resistance?

Answer 3

arterioles

Question 4

What vessels have the largest total surface area

Answer 4

Capillaries—for exchange

Question 5

What vessels are the most compliant or distensible and as such act as the blood volume store?

Answer 5

Veins

Question 6

What is Poseuille’s Law for Q (blood flow)?

Answer 6

Q= (Pi-Po)/R

[P=pressure, i=inlet, o=outlet, R=resistance]

Question 7

Resistance in a blood vessel is proportional to what 2 characteristics?

Answer 7

length and viscosity

Question 8

What is the most important determinant of resistance?

Answer 8

Radius (inversely proportional raised to 4th power)

Question 9

Does an increase of RBC raise or lower blood viscosity?

Answer 9

raise

Question 10

Blood flow to a particular organ is equal to? (equation)

Answer 10

(Q)CO=MAP/TPVR

Question 11

What are the two ways to increase mean arterial pressure (MAP)?

Answer 11

1. Increase Cardiac Output

2. Increase total peripheral vascular resistance

Question 12

What are two ways to decrease mean arterial pressure?

Answer 12

1. Decrease cardiac output?

2. Decrease total peripheral vascular resistance

Question 13

What would cause a decrease in flow but an increase in blood pressure?

Answer 13

greater resistance

Question 14

The slope of the flow/ pressure curve is inversely related to what?

Answer 14

resistance

Question 15

How do you calculate total resistance for a group of resistances in series?

Answer 15

add them

Question 16

How do you calculate total resistance for a group of resistances in parallel?

Answer 16

reciprocal of total = sum of reciprocal of individual resistances

Question 17

What results from the fact that most resistances in circulation are in parallel?

Answer 17

total peripheral vascular resistance is much less than vascular resistance within a specific vascular bed.

Question 18

What type of blood flow is streamlined, regular, orderly and has parallel layers?

Answer 18

Laminar flow

Question 19

Where is blood flow the fastest in a vessel?

Answer 19

In the center (leading edge looks like a parabola)

Question 20

What type of blood flow is disorganized with eddies and multi directional?

Answer 20

Turbulent flow

Question 21

What does high velocity, increased density, large diameter and low viscosity do to blood flow?

Answer 21

they all increase turbulence (vice versa holds true to)

Question 22

Where is most turbulent flow found within the body?

Answer 22

Ascending aorta, main pulmonary artery, just distal to stenosis

Question 23

Very turbulent flow can be diagnosed by hearing what?

Answer 23

bruits in arteries and murmurs in heart valves