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how does your heart pump blood?

Your heart pumps blood by squeezing and relaxing in a repeating cycle, using four chambers, one‑way valves, and tiny electrical signals that keep everything in rhythm. With each beat, it sends low‑oxygen blood to the lungs to pick up oxygen, then sends fresh, oxygen‑rich blood out to the rest of your body.

Quick Scoop

The heart as a pump

  • The heart is a strong muscle about the size of your fist, sitting slightly left of the middle of your chest.
  • It has four chambers: two atria on top and two ventricles below, which work together like a two‑stage pump.

Step‑by‑step blood journey

  1. Low‑oxygen blood from your body flows into the right atrium through big veins called the venae cavae.
  1. The right atrium squeezes and pushes this blood into the right ventricle through a one‑way tricuspid valve.
  1. The right ventricle contracts and pumps blood through the pulmonary valve to the lungs, where it drops off carbon dioxide and picks up oxygen.
  1. Fresh, oxygen‑rich blood returns from the lungs to the left atrium through the pulmonary veins.
  1. The left atrium squeezes and sends blood through the mitral valve into the left ventricle.
  1. The left ventricle, the strongest chamber, contracts powerfully and pumps blood through the aortic valve into the aorta, the main artery that branches out to your whole body.

Why the blood doesn’t go backwards

  • One‑way valves (tricuspid, pulmonary, mitral, aortic) act like doors that only open in one direction, stopping backflow when chambers squeeze.
  • The walls between left and right sides (septa) keep oxygen‑rich and low‑oxygen blood from mixing.

The built‑in electrical system

  • A small cluster of pacemaker cells in the sinoatrial (SA) node sends out electrical signals that start each heartbeat.
  • These signals spread through the atria, pause at the atrioventricular (AV) node, then travel down special conduction fibers so the ventricles squeeze in a coordinated way.

How often this happens

  • At rest, an adult heart usually beats about 60–100 times per minute, pumping roughly 5 litres of blood around the body each minute.
  • Over a day, that adds up to around 100,000 beats continuously delivering oxygen and nutrients and carrying away waste.

Information gathered from public forums or data available on the internet and portrayed here.