Cambridge O Level Biology · Syllabus 5090 · Transport in Humans
Artery
What is Artery?
An artery is a blood vessel that carries blood away from the heart. The blood inside it is at high pressure that surges with each contraction of the ventricle, so an artery has a thick wall containing a great deal of smooth muscle and elastic tissue and a relatively narrow lumen. The thick wall withstands the pressure without bursting, the elastic tissue stretches and recoils to smooth out the surges and help maintain pressure between beats, and the smooth muscle can alter the diameter of the lumen.
This definition is part of the Transport in Humans chapter in Cambridge O Level Biology.
Common mistakes with Artery
- “Arteries carry oxygenated blood; veins carry deoxygenated blood.” CorrectArteries carry blood away from the heart and veins carry blood towards it. The pulmonary artery carries deoxygenated blood and the pulmonary vein carries oxygenated blood, and both are named correctly.
- “Arteries always carry oxygenated blood.” Why wrongIt takes a pattern that happens to hold in the systemic circuit and treats it as a definition. WriteAn artery carries blood away from the heart. The pulmonary artery carries deoxygenated blood to the lungs.
Examiner tips on Artery
- The single most valuable habit in this topic. Whenever you state a structural feature, immediately state what it does. “The wall of an artery is thick” is worth nothing on its own. “The wall of an artery is thick, so it can withstand the high pressure of blood leaving the heart without bursting” is the mark.
- The naming rule. “Hepatic” means of the liver; “renal” means of the kidney; “pulmonary” means of the lung. Put those together with artery = away from the heart and vein = towards the heart, and eight of the nine names build themselves. Only the hepatic portal vein has to be learned as a special case.
- Arteries do not push blood. The heart provides the push. An artery withstands the pressure and, through elastic recoil, maintains it. Writing that the artery wall “squeezes each blood cell forward” loses the mark.
Questions students ask about Artery
Do arteries always carry oxygenated blood?
No. An artery is defined by direction: it carries blood away from the heart. The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs, and the pulmonary vein carries oxygenated blood from the lungs back to the heart.