Cards to the three blood vessels (arteries, veins, capillaries)

Question 1

Arteries

Answer 1

• Arteries carry blood away from the heart to the organs of your body.
• This blood is usually bright-red oxygenated blood.
• The arteries stretch as the blood is forced through them and go back into shape afterwards.
• You can feel this as a pulse where the arteries run close to the skins surface (e.g., at your wrist).
• Arteries have thick walls containing muscle and elastic fibres.
• As the blood in the arteries is under pressure, it is very dangerous if an artery is cut, because the blood will spurt out rapidly every time the heart beats.

Question 2

Veins

Answer 2

• Veins carry blood away from the organs towards your heart.
• This blood is usually low in oxygen and therefore a deep purple-red colour.
• Veins do not have a pulse.
• They have much thinner walls than arteries and often have valves to prevent the backflow of blood.
• The valves open as the blood flows through them towards the heart, but if the blood starts to flow backwards the valves close and prevent a backflow of blood.
• The blood is squeezed back towards the heart by the action of the skeletal muscle.

Question 3

Capillaries

Answer 3

• Throughout the body, capillaries form a huge network linking the arteries and the veins.
• Capillaries are narrow with very thin walls.
• This enables substances, such as oxygen and glucose, to diffuse easily out of your blood and into your cells.
• The substances produced by your cells, such as carbon dioxide, pass easily into the blood through the walls of the capillaries.