This article is about the human body as a whole. For components within the human body, see human anatomy.
[[File:|thumb|300px|Human body features displayed on bodies on which body hair and male facial hair has been removed]]
The human body is the entire structure of a human organism, and consists of a head, neck, torso, two arms and two legs. By the time the human reaches adulthood, the body consists of close to 100 trillion cells,[1] the basic unit of life.[2] These cells are organised biologically to eventually form the whole body.
Contents
1 Size, type and proportion 2 Systems 2.1 Cardiovascular system 2.2 Digestive system 2.3 Integumentary system 2.4 Lymphatic system 2.5 Musculoskeletal system 2.5.1 Bones 2.6 Nervous system 2.7 Reproductive system 3 See also 4 References 5 Further reading 6 External links
Size, type and proportion
Constituents of the human body
In a normal man weighing 60 kg
Constituent Weight [3] Percent of atoms[3]
Hydrogen 6.0 kg 63%
Oxygen 38.8 kg 25.5%
Carbon 10.9 kg 9.5%
Nitrogen 1.9 kg 1.4%
Calcium 1.2 kg 0.2%
Phosphorus 0.6 kg 0.2%
Potassium 0.2 kg 0.07%
Main article: Body proportion
The average height of an adult male human (in developed countries) is about 1.7–1.8 m (5'7" to 5'11") tall and the adult female is about 1.6–1.7 m (5'2" to 5'7") tall.[4] Height is largely determined by genes and diet. Body type and composition are influenced by factors such as genetics, diet, and exercise.
Systems
Main article: Organ systems
The organ systems of the body include the musculoskeletal system, cardiovascular system, digestive system, endocrine system, integumentary system, urinary system, lymphatic system, immune system, respiratory system, nervous system and reproductive system.
Anterior (frontal) view of the opened heart. White arrows indicate normal blood flow.