Biology B2 - Circulatory System (Blood Vessels)

what are the 3 different types of blood vessels?

arteries, veins, capillaries

explain the function of the arteries

carry the blood away from the heart

explain the function of capillaries

these are involved in the exchange of materials at the tissue

explain the function of veins

these carry the blood to the heart

at what pressure does the heart pump blood at?

high pressure

describe two properties of arteries

strong and elastic

Why are arteries elastic?

-elastic recoil helps maintain blood pressure

-allows them to stretch & spring back

how are arteries strong?

contain thick layers of muscle

Are capillaries big or small?

very small

How thick are capillaries?

one cell thick

where do arteries branch into?

capillaries

capillaries are too small to see.

what is the function of capillaries

substances are exchanged between the blood and body cells

Why do capillaries have permeable walls?

so substances can diffuse in and out

what do capillaries supply the body with?

food, oxygen, take away waste like co2

How is the rate of diffusion increased?

Larger surface area

Larger concentration gradient

Thinner exchange surface( short diffusion pathway )

why don't the walls of veins have to be as thick as artery walls?

the blood is at a lower pressure

why do veins have a bigger lumen than arteries?

To help the blood flow despite the lower pressure.

why do veins have valves?

prevent backflow, keep blooding flowing in the right direction

rate of blood flow formula?

volume of blood ÷ number of minutes