Circulation

Label the different chamber, valves no blood vessels on the diagram of the heart

a

b

c

d

e

f

g

h

i

Right atrium

Left Atrium

Pulmonary artery

Right ventricle

Vena cava

Atrioventricular valve

Pulmonary vein

Semilunar valve

Septum

______ prevent the back flow of blood

Deoxygenated blood returns to the heart via the ____ ____.

Match the following blood vessels

• Artery

• 
• Vein

• 
• Capillary

• 

Match the following blood vessels with their function

• Capillary

• Thin walled to allow exchange of substances

• Vein

• Think walled, with elastic and smooth muscle to allow it to withstand high pressure

• Artery

• Thin walled, but contains valves to prevent backflow of blood

As arteries get further from the heart, they branch into smaller vessels called arterioles. Why do these have increasing amounts of smooth muscle?