[8] The heart pumps blood with a rhythm determined by a group of pacemaker cells in the sinoatrial node. These generate an electric current that causes the heart to contract, traveling …

Oct 21, 2025 · Heart, organ that serves as a pump to circulate the blood. It may be as simple as a straight tube, as in spiders and annelid worms, or as complex as the four-chambered double …

Your heart is the main organ of your cardiovascular system, a network of blood vessels that pumps blood throughout your body.

Aug 22, 2024 · Learn about the anatomy of the heart and how its chambers, valves, and vessels work together to maintain effective blood circulation throughout the body to sustain life.

Jan 8, 2025 · Learn about the heart's anatomy, how it functions, blood flow through the heart and lungs, its location, artery appearance, and how it beats.

Jun 27, 2025 · In just 60 seconds, the average adult heart pumps about 1.5 gallons (5.7 liters) of blood. X-rays of ancient Egyptian mummies show that people had heart disease more than …

Mar 24, 2022 · This image shows the four chambers of the heart and the direction that blood flows through the heart. Oxygen-poor blood, shown in blue-purple, flows into the heart and is …

Oct 4, 2024 · Blood is carried through the body in blood vessels called arteries and veins. The process of moving blood through the body is called circulation. Together, the heart and …

May 14, 2025 · The heart is situated within the chest cavity and surrounded by a fluid-filled sac called the pericardium. This amazing muscle produces electrical impulses that cause the heart …

May 14, 2018 · The normal heart is a strong, hard-working pump made of muscle tissue. It's about the size of a person's fist. The heart has four chambers. The upper two chambers are the …