The human body has about 78 organs. An organ is a collection of tissues that is specialized to perform a specific bodily function. They vary in shape and size and are split into 11 biological systems that carry out the necessary functions of the human body.
Humans have five organs that are considered to be vital to survival: the brain, heart, kidneys, liver and lungs. The 11 organ systems include the integumentary system, the skeletal system, the muscular system, the lymphatic system and the respiratory system. Also included are the digestive system, the nervous system, the endocrine system, the cardiovascular system, the urinary system and the reproductive system.