（单词翻译:单击）
Ameloblasts- cells which differentiate1 from ectoderm and secrete2 enamel3 during tooth development.
Amino acids - building blocks of proteins containing a carboxyl group (COOH) and an amino group(NH2) both attached to the same carbon atom . The difference between the 20 common amino acids lies in the nature of a side chain the "R" group. Each amino acid, has a code of three adjacent nucleotides on the DNA4 molecule5. Amino acids are joined together by peptide bonds to form polypeptides and proteins.
Amorphous6 calcium7 phosphate - a non crystalline form of apatite which may form as much as30% of bone mineral.
Amygdala- part of the limbic system, which seems to provide the emotional assessment8 of a new sensation with the memory of a similar sensation.
Anaerobic9 respiration11 - the first step in the production of ATP is to break down glucose12. This process of glycolysis is a 10 step series of reactions leading finally to the smaller molecule pyruvate. The energy derived13 from this process is a hydrogen ion and an electron, which are both placed onto the carrier molecule as nicotinamide adenine dinucleotide (NADH+). As the pyruvate and NAD H+ are produced they could move into the mitochondria, for the nextstage of aerobic10 respiration, provided oxygen is available. If there is no oxygen, NAD H H+ is used in a process of substrate phosphorylation to form ATP. But the pyruvate builds up. It is then converted to lactic14 acid and removed to the liver. If lactic acid is not removed fast enough it causes muscle weakness and pain. Anaerobic glycolysis does not produce a high yield of energy. There are still high energy bonds remaining in the pyruvate and there is no benefit from the large yield of ATP made possible by the electron transport system in the mitochondria
Angiogenesis - the development of blood vessels15 - a key event in embryology and healing.
Ankylosis - bony fusion16 of the two surfaces of a joint17 to each other, which prevents movement. Ankylosis of the tooth root to its bony socket18 may causes root resorption.
Antibacterial - inhibiting20 the growth of bacteria.
Antibodies -are proteins called immunoglobulins which circulate in the blood and body fluids. They bind21 specifically to antigens that have induced them. Antibodies are able to inactivate22 bacterial19 toxins23, viruses and help phagocytes to engulf24 whole bacteria. They have a vital role to play in the bodies immune response to foreign proteins.
Antigens - proteins, usually foreign, which cause the bodies defense25 system to produce an antibody. Antigens may be food proteins, bacteria ,viruses or protozoa or cells from another individual(transplant).
Antrum - a hollow cave or SINUS, inside the maxillary bone which is lined by respiratory epithelium.
