Human Heart Quiz: Test Yourself

Try all ten questions before you look at the answers. Questions 1 to 8 are multiple choice; questions 9 and 10 need a short written answer, so write a sentence or two rather than a single word. The answers are printed upside down at the foot of the infographic. The worked answers below explain why each answer is right, which is where most of the learning happens.

Answer: B, the right ventricle. Oxygen-poor blood from the body collects in the right atrium, passes into the right ventricle, and the right ventricle pumps it through the pulmonary valve into the pulmonary artery and on to the lungs. The atria are receiving chambers, and the left ventricle pumps oxygen-rich blood to the body.

Answer: C, the mitral valve. It is also called the bicuspid valve because it has two flaps. Its partner on the right side, between the right atrium and right ventricle, is the tricuspid valve, with three flaps. The pulmonary and aortic valves sit at the exits of the ventricles.

Answer: D, the pulmonary veins. Veins carry blood towards the heart, and the pulmonary veins carry it from the lungs, so their blood is rich in oxygen. The pulmonary artery is the trap: it carries oxygen-poor blood the other way, from the heart to the lungs.

Answer: C, about 100,000. You can work it out: at about 70 beats a minute, 70 × 60 × 24 = 100,800 beats in a day. Over a long life that adds up to more than 3.5 billion beats.

Answer: B, the SA node. The sinoatrial node is a group of pacemaker cells in the wall of the right atrium. It fires by itself and starts every beat. The AV node passes the signal on to the ventricles after a short delay. The brain can speed the heart up or slow it down, but it does not start each beat.

Answer: B. The left ventricle needs a thicker, more muscular wall because it has to create enough pressure to push blood all the way round the body. Option A is a common mistake: both ventricles pump the same amount of blood with each beat.

Answer: C, capillaries. A capillary wall is a single layer of thin cells, and the narrowest capillaries are barely wide enough for one red blood cell. The short distance lets oxygen and glucose pass out to the cells and carbon dioxide pass in. Arteries, including the aorta, have thick muscular walls, and veins have thinner walls but still several layers.

Answer: C, William Harvey. His book De Motu Cordis appeared in 1628. Galen (2nd century AD) believed the liver made blood that the body used up. Ibn al-Nafis (13th century) correctly described the route through the lungs. Christiaan Barnard led the first human heart transplant in 1967.

Model answer: Blood flows in two loops. In the pulmonary circulation it goes from the heart to the lungs and back; in the systemic circulation it goes from the heart round the rest of the body and back. So blood passes through the heart twice on each complete circuit. A full answer names both loops and says where each one goes.

Model answer: The blood is really dark red. All blood is red; it is bright red when it carries a lot of oxygen and darker red when it carries less. Diagrams colour oxygen-poor blood blue only as a convention, so the two streams are easy to tell apart. A good answer says both that the blood is red and that the blue is just a convention.