3.2 Blood Vessels Flashcards Preview

A Level Biology > 3.2 Blood Vessels > Flashcards

Flashcards in 3.2 Blood Vessels Deck (26):
1

what is the sequence of blood vessels blood travels through?

arteries
arterioles
capillaries
venules
veins

2

(arteries) what layers does an artery have?

tough outer layer
thick muscle layer
elastic layer
thin inner lining
lumen

3

(arteries) the tough outer layer consists of what?

collagen

4

(arteries) the tough outer layer is strong and able to resist what?

pressure from outside the artery

5

(arteries) the thick muscle layer can do what?

contract to control blood flow

6

(arteries) the elastic layer helps maintain high pressure by doing what?

stretching and recoiling

7

(arteries) the thin inner lining is made of what?

endothelium

8

(arteries) the inner lining is structured how?

smooth to prevent friction
deeply folded to allow expansion

9

(arteries)what is the lumen?

central cavity through which blood flows

10

(arterioles) smaller blood vessels control blood flow from where?

arteries to capillaries

11

(arterioles) what is the structure of arterioles?

smooth muscle - control blood flow
less elastic tissue

12

(capillaries) capillaries link what?

arterioles and venules

13

(capillaries) their small lumen is just the right size for what?

red blood cells to squeeze through one at a time

14

(capillaries) capillaries have no what?

collagen
smooth muscle
elastic tissue

15

(capillaries) their endothelium is one cell thick to allow for what?

efficient diffusion

16

(capillaries) capillary networks provide a large what?

surface area for diffusion

17

(capillaries) the total cross sectional area of capillaries is greater than arterioles so blood does what?

slows allowing more time for diffusion

18

(venules) smaller veins carrying blood where?

from capillaries to veins

19

(venules) they have very thin walls and what type of cells?

muscle cells

20

(veins) take blood where?

back to the heart at low pressure

21

(veins) why do veins have a thin layer of elastic tissue and thin muscle layer?

blood is at a lower pressure

22

(veins) why do they have a large lumen?

blood is at lower pressure and flows slower

23

(veins) valves in veins prevent what?

backflow of blood

24

(veins) many veins run between where?

active muscle

25

(veins) when a muscle contracts what effect does it have on the vein?

squeeze it forcing blood back to the heart

26

(veins) how does breathing act as a pump?

pressure changes and squeezing actions move blood back to the heart

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