THE HUMAN HEART

THE HEART

The heart is a muscular organ about the size of a fist, located just behind and slightly left of the breastbone. The heart pumps blood through the network of arteries and veins called the cardiovascular system.

THE STRUCTURE

The human heart has four chambers: two upper chambers (the atria) and two lower ones (the ventricles). The right atrium and right ventricle together make up the "right heart," and the left atrium and left ventricle make up the "left heart."

THE CIRCULATORY SYSTEM

The circulatory system is a vast network of organs and vessels that is responsible for the flow of blood, nutrients, hormones, oxygen and other gases to and from cells.The heart, blood, and blood vessels make up the cardiovascular component of the circulatory system.

CIRCULATION OF BLOOD

The heart circulates blood through two pathways: the pulmonary circuit and the systemic circuit. Veins carry blood to the heart and arteries carry blood away from the heart to the rest of the body. The right heart pumps deoxygenated blood to the lungs. The lungs return oxygenated blood to the left heart. After arriving at the left heart the blood travels through the aorta to the rest of the body.

HEART FACTS

A human heart is roughly the size of a large fist.
The heart weighs between about 10 to 12 ounces (280 to 340 grams) in men and 8 to 10 ounces (230 to 280 grams) in women.
The heart beats about 100,000 times per day (about 3 billion beats in a lifetime).
An adult heart beats about 60 to 80 times per minute.
The heart pumps about 6 quarts (5.7 liters) of blood throughout the body.
The heart is located in the center of the chest, usually pointing slightly left.