Structure and Function

The function of arteries is to convey blood at high pressure away from the heart – to accomplish this task, arteries have a specialised structure:

• They have a narrow lumen (relative to wall thickness) to maintain a high blood pressure (~ 80 – 120 mmHg)
  

• They have a thick wall containing an outer layer of collagen to prevent the artery from rupturing under the high pressure

• The arterial wall also contains an inner layer of muscle and elastic fibres to help maintain pulse flow (it can contract and stretch)

Structure of an Artery

Flow of Blood

Blood flows through the arteries in repeated surges called pulses, with each pulse corresponds to a single contraction of the heart

• This blood flows at a high pressure and the muscle and elastic fibres assist in maintaining this pressure between pumps
  

The muscle fibres help to form a rigid arterial wall that is capable of withstanding the high blood pressure without rupturing

• Muscle fibres can also contract or relax to change the diameter of the lumen (vasoconstriction and vasodilation), which helps to maintain blood pressure 
  

The elastic fibres allow the arterial wall to stretch and expand upon the flow of a pulse through the lumen

• The pressure exerted on the arterial wall is returned to the blood when the artery returns to its normal size (elastic recoil)
  

• The elastic recoil helps to push the blood forward through the artery as well as maintain arterial pressure between pump cycles