Circulatory systems in animals

Why do animals need circulatory systems?

meet high metabolic demand, maintain steep concentration gradients, overcome low surface area: volume ratio, allow diffusion across large distances

What’s an open circulatory systems?

Blood is pumped into cavities around organs

What’s a closed circulatory system?

When blood is pumped into vessels

Which animals have open circulatory systems?

Insects

What’s the difference between a single and a double closed circulatory system?

In single closed circulatory system the blood passes the heart once whereas in double closed circulatory system the blood passes the heart twice

Which animals have a single closed circulatory system?

bony fish

Where does gas exchange occur in fish?

gills

What do arteroioles do?

transport blood under low pressure from arteries to capillaries

What do venuoles do?

transport blood under low pressure from capillaries to veins

Which blood vessels contain an outer layer, a muscle layer, an elastic layer, an endothelium and a lumen?

Artery, arterioles and vein

What does the outer layer contain?

collagen

Why do arteries have a thick muscle layer?

it needs to contract and relax to control blood flow

Why do arteries have thick elastic fibre layers?

it needs to stretch and recoil to maintain a high blood pressure

Why do arteries have thick outer walls?

to prevent it from bursting at high pressures

Why do arterioles have a thick muscle layers?

as they need to contract to control blood flow to capillaries

Why do arterioles have thin elastic fibre layer?

don’t need to maintain a high blood pressure

Why do veins have a thin muscle layer?

blood flow dosnt’t need to be controlled

Why do veins have a thin elastic fibre layer?

only low blood pressure is needed

Why do veins have valves?

to prevent back flow of blood

Which other vessel has the same structure as veins only smaller?

venuoles

Why do capillaries only have an endothelium and narrow lumen?

have a short diffusion distance

Which animals have double closed circulatory systems?

humans

Which vessel takes oxygenated blood from the lungs to the heart?

pulmonary vein

Which vessel takes oxygenated blood from the heart to the body?

aorta

Which vessel takes deoxygenated blood from the body to the heart?

vena cava

which vessel takes deoxygenated blood from the heart to the lungs?

pulmonary artery

Which tissue fluid?

A liquid surrounding cells with many substances and controls the exchange of substances between blood and cells

What’s the oncotic pressure?

the tendency of water to move into the blood by osmosis

which end has a lower hydrostatic pressure?

venous

which end has a higher hydrostatic pressure?

arteriole

How is lymph different to blood plasma?

contains less oxygen and nutrients but more proteins