Physiology and Health: The Structure and Function of Arteries, Capillaries and Veins

Question 1

Where does blood circulate?

Answer 1

From the heart through the arteries to the capillaries then to the veins and back to the heart

Question 2

There is a decrease in blood pressure when?

Answer 2

Blood moves away from the heart

Question 3

What are blood vessels?

Answer 3

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

Question 4

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

Answer 4

The lumen

Question 5

What is the lumen lined with?

Answer 5

A layer of cells called the endothelium

Question 6

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

Answer 6

Layers of tissues that differ between arteries, capillaries and veins

Question 7

Arteries carry blood where?

Answer 7

Away from the heart

Question 8

Blood is pumped through arteries at what pressure?

Answer 8

A high pressure

Question 9

Arteries have an outer layer of connective tissue containing what?

Answer 9

Elastic fibres and a thick middle layer containing smooth muscle with more elastic fibres

Question 10

The thick elastic walls of the arteries do what to accommodate the surge of blood after each contraction of the heart?

Answer 10

Stretch and recoil

Question 11

The smooth muscle in the walls of arteries can contract and relax causing what to control blood flow?

Answer 11

Vasoconstriction and vasodilation

Question 12

The ability of the arteries to vasoconstrict or vasodilate allows what?

Answer 12

The changing demands of the body’s tissues to be met

Question 13

During exercise the arteries supplying the muscles vasodilate, which does what?

Answer 13

Increases the blood flow

Question 14

During exercise the arteries supplying the abdominal organs vasoconstrict, which does what?

Answer 14

Reduces the blood flow to them

Question 15

Capillary walls are only one cell thick, which allows what?

Answer 15

Quick and efficient exchange of substances with tissues through their thin walls

Question 16

Veins carry blood where?

Answer 16

Towards the heart

Question 17

Veins have an outer layer of connective tissue containing what?

Answer 17

Elastic fibres but a much thinner muscular wall than arteries

Question 18

What is different about the lumen of a vein and the lumen of an artery?

Answer 18

The lumen of a vein is relatively wider

Question 19

Valves are present in veins to prevent what?

Answer 19

Backflow of blood

Question 20

Why are valves needed?

Answer 20

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

Question 21

Pressure filtration causes what?

Answer 21

Plasma to pass through capillary walls into the tissue fluid surrounding the cells

Question 22

Tissue fluid and blood plasma are similar in composition, with the exception of what?

Answer 22

Plasma proteins, which are too large to be filtered through the capillary walls

Question 23

What does tissue fluid contain and what does it do?

Answer 23

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

Question 24

Useful molecules such as glucose and oxygen diffuse into cells and carbon dioxide and other metabolic waste substances do what?

Answer 24

Diffuse out of the cells and into the tissue fluid to be excreted

Question 25

Much of the tissue fluid does what?

Answer 25

Re-enters the capillaries and returns to the blood

Question 26

What do lymph vessels do?

Answer 26

Absorb excess tissue fluid and return it as lymph fluid to the circulatory system