专业术语—口腔生理学术语A3(英文详解)（在线收听）

    Apatites- a family of calcium phosphate salts which are found in hard tissues like bone, teeth and shells.

    Apoptosis - death of a cell which is programmed by a set of specific genes. Apoptosis of chondrocytes allows osteoblasts to attach to their calcified matrix, and the epithelial cells forming webs between the fingers to die.

    Articular - one of the bones which together with the quadrate bones and the dentary, made/make up a reptile's jaw. In mammals the quadrate bone is incorporated into the middle ear as the malleus.

    Artificial mouth - a laboratory device for keeping bacteria growing in a controlled environment It allows for observing bacteria and their growth under different experimental conditions.

    Ascorbic acid - or Vitamin C is a dietary requirement for the proper formation of collagen. Deficiency causes scurvy.

    ATP - adenosine triphosphate - ATP is a convenient packet of energy used by both animals and plant cells. The energy in ATP is stored in its three negatively charged phosphate groups which are held close together, in spite of their repulsion for each other. This energy, multiplied many hundreds of thousand of times, for each cell is able to move our muscles, transport molecules across membranes and power all the cells other energy requirements. Once the energy has been used the ATP molecule now only has two phosphate groups. It needs energy now from either aerobic or anaerobic respiration to charge it up again, a process known as phosphorylation. Large stores of ATP are not kept as it is highly reactive. The long term storage of energy in animals is in carbon rich molecules, such as glycogen or fatty acids. In plants energy is stored as starch.

    Attachment, see epithelial-attachment

    Autocrine; cell messengers which are produced by the cell itself and regulate the expression of genes .

    Autonomic nervous system - controls routine body functions such as gut activity, respiration, blood pressure and heart rate. There are two main divisions the sympathetic nervous system and the parasympathetic system.

    Axon - the extension of a nerve cell, as a thin tube which may be as long a metre or a few short microns in length. The axon, like the cell body is able to depolarise and carry impulses along its length. The impulses from one axon to another nerve cell are transmitted at a synapse. Axons may be myelinated or unmeyelinated, and they may vary in diameter. Thicker, myelinated axons transmit impulses faster than thins unmeyelinated axons.