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ESA 2- Cardiovascular System > Flow through Tubes > Flashcards

Flashcards in Flow through Tubes Deck (84)
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1

What are the two major subdivisions of the vascular system?

Systemic circulation and Pulmonary circulation

2

How are the systemic and pulmonary circulations arranged?

In series with one another

3

What is each subdivision of the circulation composed of?

Arteries 
Arterioles 
Capillaries 
Venules 
Veins

4

How are most vessels of a given type arranged?

In parallel with each other

5

What must happen in order for blood to keep flowing?

Blood pressure must fall all the way from the aorta to the venae cavae

6

How is flow of blood driven through vessels?

By the gradient of pressure

7

What is flow proportional too?

The pressure difference between the ends of a vessel

8

What is the result of a higher pressure difference on flow?

Higher flow

9

What is the flow for a given pressure gradient determined by?

The resistance of a vessel

10

What is the resistance of a vessel determined by?

The nature of the fluid and the vessel

11

Define flow

The volume of fluid passing a given point per unit time

12

Define velocity

The rate of movement of fluid particles along the tube

13

How does flow differ at different points along a vessel?

It doesn't

14

When can velocity vary along the length of a vessel?

If the radius of the tube changes

15

What is the relationship between velocity and cross sectional area at a given flow?

They are inversely proportional

16

What is the velocity of vessels with a small cross sectional area at a given flow?

High

17

What is the velocity of vessels with a large collective cross sectional at a given flow?

Low

18

What vessels have a large cumulative cross sectional area?

Capillaries

19

What happens as arteries branch?

The total cross sectional area of the vascular bed increases, and thus so does flow

20

How can the flow be described in most blood vessels?

Laminar

21

What happens in laminar flow?

There is a gradient of velocity from the middle (highest), to the edge, where fluid is stationary

22

What happens as mean velocity increases?

Flow eventually becomes turbulent

23

What happens in turbulent flow?

The velocity gradient breaks down as fluid tumbles over, and the flow resistance greatly increases

24

What is flow determined by in a vessel with constant pressure?

Mean velocity

25

What does mean velocity depend on?

Viscosity of fluid 
Radius of tube

26

How does fluid move in laminar flow?

In concentric layers, with middle edges moving faster than the outer layers, and therefore the layers must slide over one another

27

What is the extent to which fluid layers resist sliding over one another known as?

Viscosity

28

What does a higher viscosity result in?

Slower flow of central layers, and a lower average velocity

29

What does viscosity determine?

The slope of the gradient of velocity

30

What does a wider tube result in at a constant gradient?

A faster middle layer