Human Systems: Circulation and Respiration

How the circulatory and respiratory systems move gases and nutrients around the body.

10 questions, free, marked as you go with a worked explanation on every one.

What this covers

Which blood vessel carries oxygen-poor blood from the heart to the lungs?
Where does gas exchange between air and blood actually take place?
What causes air to move into the lungs during inhalation?
Which component of blood transports most of the oxygen?
Which features make capillaries well suited to exchange? Select all that apply.
Why do veins contain valves while arteries generally do not?
What triggers the increase in breathing rate during exercise?
Blood travels from the right ventricle to the left atrium by which route?
At rest a person's heart pushes out 70 mL of blood per beat. During hard exercise the stroke volume rises to 105 mL per beat and the heart rate rises to 140 beats per minute. What is the cardiac output during that exercise, in litres per minute?
Use the table. Which chamber receives oxygenated blood returning from the lungs?