Question 2 Answer
a) A – Aorta
B – Vena cava (anterior)
C – Pulmonary vein
D – Right atrium
b) The site of gaseous exchange is the alveolus
ii) -large surface area to volume ratio
-good supply of blood
c) Valves allow blood to flow in one direction. If it is malfunctioning, enough blood will not reach the lungs to be oxygenated and sent back to the heart.
d) There is an increased demand by the muscles for food and oxygen while she is running. When the heart is beating faster, blood will be quickly transported to the muscles.
ii) Her muscle cells are respiring anaerobically which cause a build up of lactic acid. Lactic acid causes muscle pain/fatigue.