Lecture 9 - Overview of Circulation Flashcards Preview

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Flashcards in Lecture 9 - Overview of Circulation Deck (39):
1

Arterial P range

80-120 mmHg

2

Systemic capillary pressure range

10-35 mmHg

3

Systemic circulation P at the vena cavae

0 mmHg

4

Pulmonary systolic P

25 mmHg

5

Pulmonary diastolic pressure

8 mmHg

6

What "propels" blood forward during diastole?

Elasticity of arteries

7

What part of the circulatory system acts as "control conduits" by changing vessel diameter?

Arterioles

8

The functional portion of the circulatory system where nutrient/waste exchange occurs.

Capillaries

9

Act as a "blood reservoir"

Veins

10

Give blood distribution (%) in systemic circulation

64% veins
13% arteries
7% arterioles/capillaries

11

Give blood distribution (%) in pulmonary circulation

9% lungs
7% heart

12

Formula for blow flow in circulation.

V=F/A

V-velocity
F-blood flow
A-cross sectional area

13

Blood flow to tissues is precisely controlled according to tissue needs. This is accomplished by _____.

Changing the diameter of the muscular arterioles

14

Cardiac output is determined by the sum of all tissue flow/needs. How is this accomplished?

By the heart's response to tissue needs (primarily through SNS/PNS control)

15

What are the two major, rapidly occurring mechanisms for increasing pre-load during hypotension?

- constriction of skeletal m. compresses veins (skel m. Pump)
- construction of arterioles

*Kidneys increase BP after continued hypoTN and take time to do so*

16

What two variables primarily determine blood flow?

- pressure gradient (P1-P2: between vessel ends)
- resistance (controlled by changing vessel diameter)

17

Flow through a vessel formula

F=(P1-P2)/R

18

The two "functional parts" of the circulatory system.

Pulmonary and systemic circulation

19

Smooth ("streamlined") blood flow.

laminar

20

Along what area (center of vessel or outer edges of vessel) is blood flow velocity greater?

center (less turbulent)

21

This is rough (or "eddy current") blood flow

turbulent

22

List some causes of turbulent blood flow:

- vessel length is very long
- blood passes an obstruction/rough surface
- blood must make sharp turn

23

Turbulent blood flow is measured by what eqiatopm?

Reynold's number

24

Turbulent blood flow is directly proportional to what factors?

velocity of flow, vessel diameter, and blood density

25

Turbulent blood flow is inversely proportional to what factor?

Viscosity (increased viscosity -> more "sticky" -> decreased flow)

26

What blood component determines blood density?

Red blood cell concentration; protein concentration

27

What is meant by "viscosity" of blood?

The "stickiness" of blood

28

The tendency for turbulence is measured by _____.

The Reynold's number

29

Turbulence increases with?

velocity, blood density, and vessel diameter

30

The tendency for turbulence is inversely proportional to?

Blood viscosity

31

Force exerted by blood against a unit area of vessel wall.

Blood pressure

32

Pressure difference from systemic arteries to systemic veins

100 mmHg (why important?)

33

Constriction of blood vessels strongly _____ resistance; this mechanism of constriction occurs through the _______.

increases; sympathetic nervous system

34

Formula for resistance of vessels in parallel

1/Rtotal=1/R1+1/R2+1/R3...

35

Formula for resistance of vessels in series:

Rtotal=R1+R2+R3...

36

Measure of blood viscosity is called the _____

Hematocrit (HCt)

37

Viscosity is a measure of a fluid's _____.

Internal resistance

38

Blood vessels can undergo autoregulation between what arterial pressures?

70-175 mmHg

39

The factors that determine blood flow resistance.

Radius, viscosity, length