Circulatory System— Blood Vessels Flashcards
(14 cards)
Name the 3 types of blood vessels.
Arteries, capillaries, veins
What do arteries do?
Arteries carry blood away from the heart.
What do capillaries do?
Capillaries are involved in the exchange of materials at the tissues. They carry the blood really close to every cell in the body to exchange substances with them,
What do veins do?
Veins carry blood to the heart.
What features do arteries have that specialises them for their function?
The walls are thick because they carry blood at a high pressure. They contain thick layers of muscle to make them strong, and elastic fibres to allow them to stretch and spring back. They also have a small lumen to help maintain high blood pressure.
Arteries branch into what?
Capillaries
How thick is a capillary?
One cell thick
What makes a capillary specialised for its function?
They are one cell thick, and they have permeable walls so substances can diffuse in and out.
Capillaries join up to form what?
Veins
Are veins thick or thin?
Veins carry blood at a lower pressure, so their walls don’t need to be thick like arteries.
Do veins have valves and why?
Yes, to help prevent back flow of blood and ensure it moves in the correct direction towards the heart.
Do arteries have valves and why?
No, because the blood in arteries is pushed by the strong pressure generated by the heart’s contractions, which keeps it flowing in one direction.
Do capillaries have valves?
No,
What are valves?
Valves are structures that prevent the back flow of blood, ensuring it flows in one direction.
