（单词翻译:单击）
Ecological1 balance - astable balance in the numbers of each species in an ecosystem2. In the ecosystem of the mouth this balance is brought about by competition and cooperation between the different organism and the hosts defences which tend to control population size.
Ecosystem - a stable environment in which live a large number of different forms of life, each affecting the other. Example are a forest, desert, tidal area, soil, oral cavity, gut3.
Ectoderm - the outer of the three cell layers which form, as the clump4 of early embryonic5 cells begins to differentiate6. The ectoderm will form the epidermis7 of the skin and the nervous system. The other two layers are the mesoderm and the endoderm.
Ectomesenchyme - a name given to dental MESENCHYME which reflects its partly ectodermal origin.
Eicosanoids - are a class of hormones8 which are all made from phospholipids. They include prostaglandins, thromboxanes, and leucotriens.
Elastic9 fibres -are long, thin, ribbons-like fibres, sometimes even sheet-like. They are composed of a central core of elastin, a rubbery protein, surrounded by glycoprotein microfilaments. Elastin is found all over the body but particularly in the walls of blood vessels10 and in our vocal11 chords.
Electron - the negatively charged elements of an atom which circle the nucleus12. If an electron is lost the atom becomes a relatively13 positively14 charged ion. It has been ionised .
Electron Transport System- Hydrogen ions produced during the 3 preparatory steps of aerobic15 respiration16 are carried by nicotinamide adenine dinucleotide (NAD). The hydrogen ion plus one electron form NADH, which is taken to the electron transport system. This transport system is run by a series of 5 molecules18. The first, removes the two electrons from NADH,( one comes from the hydrogen atom, leaving behind a hydrogen ion). These two electrons, bounce from the first molecule17 in the transport system to the second, third, forth19 and then last one, cytochrome oxidase, which finally places the electrons onto oxygen gas O2. The electron rich oxygen atoms are attractive to the hydrogen ions and they combine to form water. (Oxygen in the process of aerobic respiration acts therefore as an electron acceptor). In the process of bouncing "downhill" the electrons have released sufficient energy to power up a small battery. This battery has been made by pumping hydrogen ions out of the inner membrane20 of the mitochondria. The collection of hydrogen ions outside, piles up and their electrical pressure mounts. They want to get back across the membrane, and are allowed, one at a time to pass back through the enzyme21 ATP synthase. This enzyme sits like a water wheel in the cell membrane, turned by the passage of hydrogen ions. Its turning wheel builds an ATP molecule in every turn. The wheel may be going at about 200 revolutions per second, powering the synthesis of an ATP molecule with each turn. ATP formed in this way takes a while but can be sustained to fuel the body during aerobic exercise. When the demand for power exceeds this rate, the cells have to rely on anaerobic22 respiration.
Electrostatic - a force generated by differences in electric charge of two particles.
