Circulation

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

a

b

c

d

e

f

g

h

i

Atrioventricular valve

Right ventricle

Semilunar valve

Pulmonary artery

Pulmonary vein

Left Atrium

Vena cava

Septum

Right atrium

(a)   prevent the back flow of blood

Deoxygenated blood returns to the heart via the ____ ____.

(a)  

Match the following blood vessels

• Artery

• 
• Vein

• 
• Capillary

• 

Match the following blood vessels with their function

• Vein

• Thin walled to allow exchange of substances

• Capillary

• 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?