Cardiovascular System Trivia

Your heart beats around 100,000 times a day without you ever having to think about it, quietly pushing blood through a network of vessels that would stretch tens of thousands of miles if laid end to end. This quiz covers the essentials of how that system works, from the heart's four chambers to the vessels and cells that do the actual delivery work.

Eleven questions, no stethoscope required.

The Heart's Engine Room

The heart is really two pumps working in sync. The right side sends oxygen-poor blood to the lungs, while the left side takes the newly oxygenated blood and sends it out to every tissue in the body. That second job requires more muscle, which is why the left ventricle has noticeably thicker walls than the right.

• The SA node fires the electrical signal that starts each heartbeat.
• Valves between chambers keep blood flowing in one direction only.
• The aorta is the single largest artery, branching into progressively smaller vessels.

Blood Vessels and the Return Trip

Arteries carry blood away from the heart under high pressure, which is why an arterial injury bleeds so dramatically. Veins have the tougher, less glamorous job of returning blood against gravity, aided by one-way valves and the squeeze of surrounding muscles. Between the two sit the capillaries, vessels so narrow that red blood cells pass through single file, exchanging oxygen and nutrients with tissue along the way.