Circulatory System - Blood Vessels Flashcards
What are the 3 types of blood vessels?
arteries, capillaries and veins.
What do the arteries do?
Carry blood under pressure as the walls are strong and elastic and they carry blood away from the heart.
What do arteries contain?
thick walls as they contain layers of muscle to make them strong and spring back they also have a whole down the middle called lumen
How are capillaries formed?
Arteries branch into capillaries
What do capillaries contain?
Thin walls only one cell thick to increase rate of diffusion by decreasing the distance over it occurs.
What do capillaries do?
carry blood really close to every cell in the body to exchange substances with them
What do capillaries supply?
they supply food and oxygen and take away waste materials eg. co2
What makes substances diffuse easily in and out of capillaries?
permable walls
What is the purpose of veins?
To take blood back to the heart, they have valves to keep the blood flowing in the correct direction.
How are veins formed?
Capillaries join up to form veins
Why don’t the walls need to be as thick in the veins?
the blood is at a lower pressure
What helps the blood flow in veins?
the lumen is bigger
what is the calculation for blood flow?
rate of blood flow = volume of blood / number of minutes
