Human organs

An organ is a structure made of several tissues working together to perform a specific function. The major organs of the human body each play a defined role, and they cooperate within organ systems to keep the body alive. Because many organs operate through continuous movement — a beating heart, expanding lungs, the churning of the stomach — animations can show their working in a way that a labelled diagram cannot.

The heart is a muscular pump that drives blood around the body, contracting rhythmically to supply tissues with oxygen and nutrients. The lungs are the main organs of breathing; air drawn into them passes into millions of tiny air sacs where oxygen enters the blood and carbon dioxide leaves it. The stomach receives swallowed food, mixes it with acid and enzymes, and begins the digestion of proteins before passing the contents to the intestines.

The liver is one of the body's most versatile organs: it processes nutrients absorbed from food, stores energy, produces bile to aid digestion, and breaks down many toxins and waste products. Other major organs include the brain, which controls the nervous system; the kidneys, which filter the blood and form urine; and the skin, the body's largest organ, which protects against the environment and helps regulate temperature. Skeletal muscles such as the biceps, though not internal organs in the usual sense, are themselves organs that produce movement.

Frequently asked questions

What is an organ?

An organ is a structure built from several tissue types that work together to carry out a particular function, such as the heart pumping blood.

What does the liver do?

The liver processes nutrients, stores energy, produces bile for digestion, and breaks down toxins and waste products in the blood.

How do the lungs supply oxygen to the body?

Air reaches tiny sacs in the lungs where oxygen passes into the blood and carbon dioxide passes out to be exhaled.