abductors - muscle taking a limb or the jaw away from the body.
acetyl choline - aneurotransmitter substance found at all cholinergic synapses including those of motoneurones at the neuromuscular junction.
acini - the secreting units of a gland. each acinus is a sack-like structure, lined by secreting cells. the sack opens out into a tubule.
adductors - muscle bringing a limb or the jaw towards the body.
adhesion - to form a chemical bond of attachment between two surfaces (see ligand and lectin).
adrenalin - see epinephrine.
aerobic respiration -a type of respiration which requires oxygen and in which glucose is broken down to release energy in a series of steps. the end products are carbon dioxide and water. step 1;glucose is broken down to pyruvic acid in the cell cylasm with the release of 4 hydrogen atoms. step 2; pyruvic acid is oxidised to acetylcoenzyme a (acetyl coa), with the release of 4 further hydrogen atoms. step 3; in the kreb cycle, 16 atoms of hydrogen are released. at all stages the hydrogen atoms are used to form the high energy molecule adenosine triphospate (atp) via the electron transport system . see also anaerobic respiration .
affected dentine - dentine which has been demineralised by acids in advance of invading caries bacteria. a distinction is made between affected dentine and infected dentine, because affected dentine is able to remineralise and should not be removed during cavity preparation.
aggregate - clumps or collections of small particles or bacteria .
alveolar bone - bone which develops around the roots of the teeth to hold them firmly in place. see gomphosis. if the teeth are extracted, the alveolar bone resorbs away. alveolar bone consists of both trabecula and cortical types of bone.
