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By mass, human cells consist of 65-90% water (H₂O), and a significant portion is composed of carbon-containing organic molecules. Oxygen therefore contributes a majority of a human body's mass, followed by carbon. 99% of the mass of the human body is made up of the six elements oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Image File history File links Wikitext. ... Image File history File links Broom_icon. ...

(from Chang, Raymond (2007). Chemistry, Ninth Edition. McGraw-Hill, p. 52. ISBN 0-07-110595-6. ) General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... For other uses, see Carbon (disambiguation). ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... For other uses, see Calcium (disambiguation). ... General Name, symbol, number phosphorus, P, 15 Chemical series nonmetals Group, period, block 15, 3, p Appearance waxy white/ red/ black/ colorless Standard atomic weight 30. ... General Name, symbol, number potassium, K, 19 Chemical series alkali metals Group, period, block 1, 4, s Appearance silvery white Standard atomic weight 39. ... General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Standard atomic weight 32. ... General Name, symbol, number chlorine, Cl, 17 Chemical series halogens Group, period, block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... For sodium in the diet, see Edible salt. ... General Name, symbol, number magnesium, Mg, 12 Chemical series alkaline earth metals Group, period, block 2, 3, s Appearance silvery white solid at room temp Standard atomic weight 24. ... For other uses, see Iron (disambiguation). ... BIC pen cap, about 1 gram. ... For other uses, see Cobalt (disambiguation). ... For other uses, see Copper (disambiguation). ... General Name, symbol, number zinc, Zn, 30 Chemical series transition metals Group, period, block 12, 4, d Appearance bluish pale gray Standard atomic weight 65. ... For the record label, see Iodine Recordings. ... For other uses, see Selenium (disambiguation). ... Distinguished from fluorene and fluorone. ...

Other elements necessary for human life (see dietary mineral) are: Dietary minerals are the chemical elements required by living organisms, other than the four elements carbon, hydrogen, nitrogen, and oxygen which are present in common organic molecules. ...

• manganese
• molybdenum
• nickel

Besides these elements that are necessary for life, our bodies contain trace quantities of most other elements, including some that are harmful, such as mercury, cadmium, and lead. General Name, symbol, number manganese, Mn, 25 Chemical series transition metals Group, period, block 7, 4, d Appearance silvery metallic Standard atomic weight 54. ... General Name, Symbol, Number molybdenum, Mo, 42 Chemical series transition metals Group, Period, Block 6, 5, d Appearance gray metallic Standard atomic weight 95. ... For other uses, see Nickel (disambiguation). ... General Name, Symbol, Number mercury, Hg, 80 Chemical series transition metals Group, Period, Block 12, 6, d Appearance silvery Standard atomic weight 200. ... General Name, Symbol, Number cadmium, Cd, 48 Chemical series transition metals Group, Period, Block 12, 5, d Appearance silvery gray metallic Standard atomic weight 112. ... For Pb as an abbreviation, see PB. General Name, Symbol, Number lead, Pb, 82 Chemical series Post-transition metals or poor metals Group, Period, Block 14, 6, p Appearance bluish gray Standard atomic weight 207. ...

The composition can also be expressed in terms of chemicals, such as:

• water
• proteins--including those of hair, connective tissue, etc.
• fats (or lipids)
• apatite in bones
• carbohydrates such as glycogen and glucose
• DNA
• dissolved ions such as sodium, potassium, chloride, bicarbonate, phosphate
• dissolved [[gas]es such as oxygen, carbon dioxide, and nitrogen oxide

Body composition can also be expressed in terms of various types of material, such as: Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... For the musical, see Hair (musical). ... Connective tissue is one of the four types of tissue in traditional classifications (the others being epithelial, muscle, and nervous tissue. ... For other uses, see FAT. Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. ... Some common lipids. ... Apatite is a group of phosphate minerals, usually referring to hydroxylapatite, fluorapatite, and chlorapatite, named for high concentrations of OH-, F-, or Cl- ions, respectively, in the crystal. ... Carbohydrates (literally hydrates of carbon) are chemical compounds that act as the primary biological means of storing or consuming energy, other forms being fat and protein. ... This article does not cite any references or sources. ... Glucose (Glc), a monosaccharide (or simple sugar), is an important carbohydrate in biology. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... This article is about the electrically charged particle. ... For sodium in the diet, see Edible salt. ... General Name, symbol, number potassium, K, 19 Chemical series alkali metals Group, period, block 1, 4, s Appearance silvery white Standard atomic weight 39. ... The chloride ion is formed when the element chlorine picks up one electron to form an anion (negatively-charged ion) Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. ... For baking soda, see Sodium bicarbonate In inorganic chemistry, a bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. ... A phosphate, in inorganic chemistry, is a salt of phosphoric acid. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Standard atomic weight 15. ... Carbon dioxide is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... The term nitrogen oxide is a general term and can be used to refer to any of these oxides (oxygen compounds) of nitrogen, or to a mixture of them: Nitric oxide (NO), nitrogen(II) oxide Nitrogen dioxide (NO2) Dinitrogen monoxide (N2O) (Nitrous oxide) Dinitrogen trioxide (N2O3) Dinitrogen tetroxide (N2O4) Dinitrogen... In physical fitness, body composition is used to describe the percentages of fat, bone and muscle in human bodies. ...

• muscle
• fat
• bone and teeth
• brain and nerves
• connective tissue
• blood -- 7% of body weight. See List of human blood components.
• lymph
• contents of digestive tract, including intestinal gas
• urine
• air in lungs

There are many species of bacteria and other microorganisms that live on or inside the healthy human body. In fact, 90% of the cells in (or on) a human body are microbes, by number (much less by mass or volume) (from Glausiusz, Josie. Your Body Is a Planet. Retrieved on 2007-09-16.). A top-down view of skeletal muscle Muscle (from Latin musculus little mouse [1]) is contractile tissue of the body and is derived from the mesodermal layer of embryonic germ cells. ... For other uses, see FAT. Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. ... This article is about the skeletal organs. ... Types of teeth Molars are used for grinding up foods Carnassials are used for slicing food. ... For other uses, see Brain (disambiguation). ... Nerves (yellow) Nerves redirects here. ... Connective tissue is one of the four types of tissue in traditional classifications (the others being epithelial, muscle, and nervous tissue. ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... List of human blood components and their concentrations Categories: Blood | Lists ... In mammals including humans, the lymphatic vessels (or lymphatics) are a network of thin tubes that branch, like blood vessels, into tissues throughout the body. ... For the Physics term GUT, please refer to Grand unification theory The gastrointestinal or digestive tract, also referred to as the GI tract or the alimentary canal or the gut, is the system of organs within multicellular animals which takes in food, digests it to extract energy and nutrients, and... Flatulence consists of gases that are produced by symbiotic bacteria and yeasts living in the gastrointestinal tract of mammals and are released through the anus. ... This article or section is in need of attention from an expert on the subject. ... Look up air in Wiktionary, the free dictionary. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... A cluster of Escherichia coli bacteria magnified 10,000 times. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st Century. ... is the 259th day of the year (260th in leap years) in the Gregorian calendar. ...