State the blood vessels A, B and C in the diagram.

A:

B:

C:

Distinguish between the pulmonary and systemic circulatory systems.

Explain the changes in blood distribution that occur during an endurance training run.

A: <inferior> vena cava ✔

B: pulmonary artery ✔

C: aorta ✔

pulmonary involves blood flow to the lungs <from the heart> whereas systemic involves blood flow to the body <from the heart> ✔

pulmonary from the right ventricle to the lungs and systemic from the left ventricle (through aorta) to (organs of) the body ✔

pulmonary from the lungs to the left atrium and systemic from the body to the right atrium ✔

pulmonary blood leaving the heart is low in oxygen whereas systemic blood leaving the heart is high in oxygen ✔

pulmonary blood returning to the heart is high in oxygen whereas systemic blood returning to the heart is low in oxygen ✔

pulmonary circulation is under lower pressure than systemic circulation ✔

blood moves to working muscles as the need for oxygen and nutrients increases / need to get rid of wastes from these regions increase ✔

blood moves to working muscles because of vasodilation ✔

blood distribution to regions such as stomach / liver / kidneys decreases because of vasoconstriction ✔

blood flow will increase to heart and lungs as they are vital for moving blood and getting rid of wastes and getting oxygen ✔

increased acidity / CO₂ / temperature detected by the brain trigger vasodilation and vasoconstriction ✔

Reason must be given for each change stated.

Almost all students could name one vessel and a large number could do all three but it seemed that a surprising number had not seen a diagram like this before.

Similar to 2a; this was well done by some and poorly handled by others.

Vasodilation, vasoconstriction was picked up by only a handful of candidates. Overall, this was poorly answered.