circulatory system -blood vessels

What are arteries and what does they carry/do

Arteries are blood vessels which carry blood away from the heart towards the organs

Why are the blood inside arteries at high pressures.

And what does the arteries have bc of this

Because arteries carry blood directly from the heart and the heart pumps the blood out at high pressures

So the artery walls are strong and elastic. They contain thick layers of muscle to make them strong, and elastic fibres to allow them to stretch and spring back. The walls are thick compared to the size of the lumen

Name the 3 main types of blood vessels.

Arteries , veins , capillaries

What is the role of the capillaries?

Arteries branch into capillaries, capillaries exchange nutrients and oxygen with tissues. They carry the blood really close to every cell in the body to exchange substances with them , they supply food and oxygen to every cell and take away waste products like carbon dioxide.

How are capillaries adapted for their function

Capillaries are really tiny. They have permeable walls, so the substances being exchanged with the cells can diffuse in and out. Their walls are usually only one cell thick, this increases the rate of diffusion by decreasing the distance over which it occurs. Capillaries are also very narrow this gives them a large surface area compared to their volume, which also increases the rate of diffusion.

What is the function of veins

Carry blood back to the heart

how are veins structure/ how’s it adapted for its function

Capillaries eventually join up to form veins. Veins carry blood to the heart. The blood is at lower pressure in the veins so the walls don’t need to be as thick as artery walls. Veins have a bigger lumen than arteries to help the blood flow despite the lower pressure . they also have valves to help keep the blood flowing in the right

How do you calculate the rate of blood flow

Rate of blood flow = volume / number of minutes