The Structure & Function of Arteries, Capillaries & Veins

Question 1

What blood vessels does blood travel through?

Answer 1

Arteries, arterioles, capillaries, venules and veins.

Question 2

What happens during circulation?

Answer 2

Blood circulates from the heart through the blood vessels before returning to the heart.

Question 3

What are blood vessels?

Answer 3

Tubes with walls composed of different tissues dependent on the fiction of the vessel.

Question 4

What is the Lumen?

Answer 4

The central space/cavity of the blood vessels.

Question 5

What is the layer of cells that line the lumen known as?

Answer 5

The endothelium.

Question 6

What do arteries do?

Answer 6

Carry blood AWAY from the heart.

Blood is pumped through arteries at a high pressure.

Question 7

What is the structure of arteries?

Answer 7

Arteries have an outer layer of connective tissue containing elastic fibres and a thick middle layer containing smooth muscle with more elastic fibres.

Question 8

How do arteries cope with the surge of blood after each contraction of the heart?

Answer 8

Their thick elastic walls stretch and recoil.

Question 9

What do the smooth muscles in the walls of the arterioles do?

Answer 9

Contract and relax, causing vasoconstriction and vasodilation to control blood flow.

Question 10

What is vasoconstriction?

Answer 10

The narrowing of blood vessels to reduce blood flow through the arterioles.

Question 11

What is vasodilation?

Answer 11

The widening of blood vessels to increase blood flow through the arterioles.

Question 12

True or false: during exercise the arterioles supplying the muscles vasodilate which increases the blood flow.

Answer 12

True.

Question 13

True or false: During exercise the arterioles supplying the abdominal organs vasoconstrict which reduces the blood flow to them.

Answer 13

True.

Question 14

Arteries branch out into smaller blood vessels called ________?

Answer 14

Arterioles.

Question 15

The arterioles branch into smaller blood vessels called _________?

Answer 15

Capillaries.

Question 16

How is blood transported from the arterioles to the venules?

Answer 16

Through a dense network of capillaries.

Question 17

Explain the structure of capillaries.

Answer 17

Capillaries are one cell thick which allows quick and efficient exchange of materials.
Capillaries allow exchange of substances with tissues.

Question 18

Capillaries merge into one another, producing wider blood vessels called ________ which finally form ______.

Answer 18

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 veins?

Answer 20

Veins have an outer layer of connective tissue containing elastic fibres but a much thinner muscular wall than arteries.
The lumen of a vein is relatively wider than that of an artery.

Question 21

What is the function of valves?

Answer 21

Valves are present in veins to prevent the backflow of blood. Valves are needed as the blood is flowing back to the heart at low pressure and generally against the force of gravity.

Question 22

True or false: blood in the arterioles is at a lower pressure than the blood in the capillaries.

Answer 22

False: blood in the arterioles is at a higher pressure than the blood in the capillaries.

Question 23

What does higher blood pressure at the arteriole end of the capillaries result in?

Answer 23

Pressure filtration, forcing the plasma with small soluble molecules, out of the capillaries into the tissues.

Question 24

What is pressure filtration?

Answer 24

Passage of molecules through membranes under pressure.

Question 25

What is plasma?

Answer 25

Liquid component of the blood.

Question 26

What is Tissue fluid?

Answer 26

Fluid which bathes cells in tissues; derived from blood.

Tissue fluid is similar to 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.
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 28

By which process does tissue fluid re-enter the capillaries and through which part?

Answer 28

Tissue fluid re-enters the capillaries at the venule end of the capillary bed by osmosis.

Question 29

True or false: pressure filtration forced more water out of the capillaries than the-enters by osmosis.

Answer 29

True.

Question 30

What happens to excess tissue fluid?

Answer 30

Excess tissue fluid enters the lymph vessels and passes into the lymphatic system. The lymph fluid is then returned to the circulatory system.

Question 31

Give an account of the structure of Lymph vessels.

Answer 31

Lymph vessels have thin walls and valves.