中文字幕免费精品_亚洲视频自拍_亚洲综合国产激情另类一区_色综合咪咪久久

Calcium-binding pro 0

calcium-binding proteins - proteins which have the ability to store calcium ions and to bind onto calcium in the hydroxyapatite of the enamel surface.

calculus - a hard deposit of calcified plaque which is found around the neck of the tooth. when it is above the free gingival margin (supra-gingival) it is white and chalky. when it is below (sub-gingival) it is dark and hard.

candidiasis - an infection caused by candida albicans, a normal commensal of the mouth; also called "thrush";

capsule - a fibrous casing surrounding an organ or gland; also a coating for some bacteria which protects them, from the bodies immune system. it is only the variety of pneumococcus sp. which has a capsule which is able to pass the immune barrier and cause pneumonia

caries - the demineralisation, and breakdown of tooth structure by plaque acids.

cariogenic - likely to cause caries. sugar is cariogenic because it supports the growth of plaque

carious plaque - types of plaque which are associated with caries .

carnivorous - an animal whose diet consists of animal tissue.

cej - see cemento-enamel junction.

cell junctions - sites on the cell membrane where cells attach to neighbouring cells. there are three main types. 1. adhering junctions, which anchor cells to each other to resist separation. they may form a belt of adhesions between cells (as between muscle cells) or spot attachments like desmosomes which hold epithelial cells together. 2. tight junctions have no space between the membranes and allow no leakage between cells. they are found between cells of a secreting glands and between endothelial cells of blood vessels to prevent fluid leaking out. 3. gap junctions are channels which allow transfer of small molecules like ions, sugars and amino acids, between cells.

cemento-enamel junction- the junction between the enamel covering the crown of the tooth and the cementum covering its root. often referred to as the cej.

cementoblasts - cells of mesenchyme origin, induced by proteins from cells of ectodermal origin, to form a layer of cementum around the roots of teeth.

cementum - a thin layer of bone-like material covering the roots of teeth and sometimes the enamel surface, containing both extrinsic and intrinsic fibres.

central nervous system - the brain and spinal cord. the nerves which leave the spinal cord and brain comprise the peripheral nervous system.

chemotaxis - the movement of cells in response to chemical messengers. the movement of neutrophils and macrophages into damaged tissues is brought about by signals released by damaged tissues, and bacterial products.. the term applies to the movement of any organism attracted by a specific chemical, which may be a suitable nutrient.

cholinergice - cell receptors specific for the neurotransmitter acetyl choline. cholinergic receptors are found at neuromuscular junctions of muscle fibres and at all the synaptic junctions of the parasympathetic nervous system. they are also found at the pre- ganglionic synapse of the sympathetic nervous system.

chondroitin sulphate - the major glycosaminoglycan of cartilage , the other being keratan sulphate.

chromosomes - structures in the nucleus of a cell which appear visible during cell division. each chromosome (humans have 24) is a tightly coiled string of dna wound round a protein.

clearance - the removal by swallowing, of substance in the mouth. clearance is dependent on the completeness of swallowing and the rate of flow of saliva.

clones - a family of cells, or organisms, which are all identical to a single parent. they are produced by asexual reproduction. when a b lymphocytes has recognised a foreign antigen, it provides millions of identical daughter cells in order to produce the specific antibodies in large quantities.

clotting - see blood clotting

code - the code of nucleotides is written in "words" of three letters using an"alphabet" of four "letters". these four components of the code are adenine, thymine, cytosine, and guanine.

collagen - the most common protein found in the body. it has a fibrous structure and makes up the main organic component of bone and dentine, and the fibres of tendons and ligaments.

collagenase - an enzyme produced by fibroblasts which breaks down collagen fibres. the fibroblast recycles the component amino acids, and secretes new collagen fibres. this process of remodelling occurs throughout life. osteoclasts also secrete collagenases in order to remove bone matrix. several bacteria are able to secrete collagenases and are thus able to break down and penetrate through collagen fibres in the periodontal ligament.

colonies - communities of organisms which have taken up residence in a habitat .

competency - the ability of a cell to respond to messengers which could cause it to differentiate into a more specialised cell. some cells, like pericytes remain competent throughout life, whereas others, such as the oral epithelium, are only able to form an tooth bud during the 12th to 16th week of foetal development.