Structure and function of arteries, capillaries and veins

Question 1

What are the blood vessels which blood circulate from the heart called?

Answer 1

Arteries, arterioles, capillaries, venules and finally veins, before returning to the heart

Question 2

What are blood vessels?

Answer 2

Tubes with walls composed of different tissues dependent on the function of the vessel

Question 3

What is the central space or cavity of the blood vessels called?

Answer 3

The lumen

Question 4

What is lumen lined with?

Answer 4

A layer of cells called endothelium

Question 5

What is the endothelium lining the central lumen of blood vessels surrounded by?

Answer 5

Layers of tissue that differ between arteries, capillaries and veins

Question 6

What does arteries do?

Answer 6

Carry blood away from the heart

Question 7

What pressure is the blood pumped through the arteries?

Answer 7

At a high pressure

Question 8

What does arteries have?

Answer 8

An outer layer containing smooth muscle with more elastic fibres

Question 9

What do the thick elastic walls of the arteries do?

Answer 9

Stretch and recoil to accommodate the surge of blood after each contraction of the heart

Question 10

What can the smooth muscle in the walls of the arterioles do?

Answer 10

Contract or relax causing vasoconstriction and vasodilation to control blood flow

Question 11

What does the ability of the arterioles to vasoconstrict or vasodilate allow?

Answer 11

The changing demand of the body’s tissue to be met

Question 12

What happens to the arterioles supplying the muscle vasodilate during exercise?

Answer 12

Increases the blood flow

Question 13

What happens to the arterioles supplying the abdominal organs during exercise?

Answer 13

Reduces the blood flow to them

Question 14

What do arteries branch into?

Answer 14

smaller blood vessels called arterioles

Question 15

From the arterioles where is the blood transported?

Answer 15

To the venules by passing through a dense network or bed of capillaries

Question 16

Describe the walls of capillaries?

Answer 16

They’re only one cell thick, which allows quick and efficient exchange of materials

Question 17

What do capillaries allow to exchange?

Answer 17

substances with tissues

Question 18

What happens when capillaries merge into one another

Answer 18

produce wider blood vessels called venules, which finally form veins

Question 19

What do veins do?

Answer 19

Carry blood towards the heart

Question 20

What is the structure of a vein?

Answer 20

Outer layer of connective tissue containing elastic fibres but a much thinner muscular wall than arteries

Question 21

What is the difference between a lumen of a vein and of an artery?

Answer 21

The lumen of a vein is relatively wider than of an artery

Question 22

Why are valves present in veins?

Answer 22

To prevent the backflow of blood

Question 23

Why are valves needed?

Answer 23

As the blood is flowing back to the heart at low pressure and generally against the force of gravity

Question 24

Comparison of blood in arterioles than capillaries

Answer 24

Arterioles is at a higher pressure than the blood in the capillaries

Question 25

What is the result of higher blood pressure at the arteriole end of the capillary bed?

Answer 25

It results in pressure filtration, forcing the plasma, with small soluble molecules, out of the capillaries into the tissues

Question 26

What is tissue fluid similar to?

Answer 26

Blood plasma but does not contain plasma proteins

Question 27

What does tissue fluid contain?

Answer 27

Glucose, oxygen and dissolved substances, which supply the tissues with all their requirements

Question 28

What happens to the useful and waste substances?

Answer 28

Useful molecules such as glucose and oxygen diffuse into cells and carbon dioxide and waste substances diffuse out of the cells and into the tissue fluid to be excreted

Question 29

How does the tissue fluid re-enter?

Answer 29

Through capillaries at the venule end of the capillary bed by osmosis

Question 30

What does pressure filtration force?

Answer 30

More water out of the capillaries than re-enters by osmosis

Question 31

Where does excess tissue fluid enter?

Answer 31

The lymph vessels and passes into lymphatic system

Question 32

Structure of lymph vessels

Answer 32

Have thin walls and valves

Question 33

What does the lymphatic system return?

Answer 33

The lymph fluid to the circulatory system