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Flashcards in Lecture 9 Overview of Circulation Deck (79)
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1

Blood flow resistance is indirectly proportional to which of the following?
a. viscosity
b. vessel diameter
c. density
d. both A and C

b. vessel diameter

2

Reynolds number is a measure of which of the following parameters?
a. Tendency for turbulence
b. Blood pressure
c. Conductance
d. Resistance

a. Tendency for turbulence

3

84% of the blood volume is in the systemic circulation. Of this, 64% is in which of the following vessels?
a. Capillaries
b. Systemic arterioles
c. Veins
d. Arterioles

c. veins

4

Which of the following represents the viscosity of blood with a hematocrit of 38-42?
a. 1.5
b. 3.0
c. 38
d. 42

b. 3.0

5

Arterial pressure from _____ mm Hg (systolic) to _____ mm Hg (diastolic)

120, 80

6

When does Arterial pressure drop to 0 mm Hg?

By the time is reaches the termination of the vena cava

7

Systemic capillary pressure varies from _____ mm Hg to _____ mm Hg

35, 10

8

In pulmonary circulation, what is the systolic pulmonary artery pressure?

25 mm Hg

9

In pulmonary circulation, what is the pulmonary diastolic pressure?

8 mm Hg

10

In circulation, what is the function of the arteries?

Transport under high pressure

11

In circulation, what is the function of the arterioles?

Control conduits

12

In circulation, what is the function of the capillaries?

exchange between blood and extracellular fluid

13

What percent of blood volume is in the systemic circulation?

84%

14

What percent of systemic blood volume is in the veins?

64%

15

What percent of systemic blood volume is in the arteries?

13%

16

What percent of systemic blood volume is in the systemic arterioles and capillaries?

7%

17

What percent of blood volume is in the heart and lungs?

16%

18

Formula for Velocity of Blood Flow

V = F/A
V (velocity of blood flow)
F (volume of blood flow)
A (vascular cross-sectional area)

19

How fast does blood travel in the aorta at rest?

33 cm/sec

20

How fast does blood flow in the capillaries at rest?

0.3 mm/sec

21

What precisely controls the rate of blood flow to each tissue?

It is almost always precisely controlled in relation to the tissue need

22

The cardiac output is controlled mainly by what?

The sum of all the local tissue flows

23

True or False
Arterial pressure regulation is generally DEPENDENT of either local blood flow control or cardiac output control

FALSE
Arterial pressure regulation is generally INDEPENDENT of either local blood flow control or cardiac output control

24

In each tissue, ________ monitor tissue needs

microvessels

25

When a tissue is in need, the heart responds to the demand. What type of signals may be needed to help the heart pump the required amount of blood?

Nerve signals

26

If arterial pressure falls below 100 mmHg, nervous reflexes: (4)

Increase force of heart pumping
Constrict large venous reservoirs
Generally constrict most of the arterioles throughout the body (increases arterial pressure)
Kidneys may later play role in pressure control

27

What factors determine blood flow?

Pressure difference between the two ends of a vessel (pressure gradient)
Impediment of blood flow through the vessel (resistance)

28

How do we calculate the flow through a vessel?

F = deltaP/R

29

Flow is _______ (directly or indirectly) proportional to pressure

Directly

30

Flow is _______ (directly or indirectly) proportional to resistance

Indirectly