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/ˌadapˈtāSHən/ Noun, pl. adaptations 1. A trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation. ( 2. (Ecology) The adjustment or changes in behavior, physiology, and structure of an organism to become more suited to an environment. ( 3. (Ophthalmology) The ability of the eye to adjust to various light intensities by regulating the pupil of the quantity of light entering the eye. ( 4. (Neurology) The decline in the frequency of firing of a neuron, particularly of a receptor, to changed, constantly applied environmental conditions. ( 5. (Dentistry) a. The proper fitting of a denture. b. The degree of proximity and interlocking of restorative material to a tooth preparation. c. The exact adjustment of bands to teeth. ( Word origin: From French adaptation, from Medieval Latin adaptatio, from Latin...

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tr.v. adducted, adducting, adducts 1.(Physiology) To draw inward toward the median axis of the body or toward an adjacent part or limb. ( 2. A movement which brings a part of the anatomy closer to the middle sagittal plane of the body. It is opposed to abduction. ( 3. (Chemistry) A chemical compound that forms from the addition of two or more substances. ( adduction (noun) adductive...

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Noun, pl. adductions 1. (Science: anatomy, orthopaedics) Movement of the limbs toward the medial plane of the body or toward the axial line of the limb....

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/ˈadnˌēn/ Noun 1. A nucleobase (a purine derivative) with a variety of roles in biochemistry including cellular respiration, in the form of both the energy-rich adenosine triphosphate (ATP) and the cofactors nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD), and protein synthesis, as a chemical component of DNA and RNA.[2] The shape of adenine is complementary to either thymine in DNA or uracil in RNA. ( 2. (Biochemistry) A nitrogenous base, one member of the basepair A-T (adenine-thymine). ( 3. (Biochemistry) Purine base found in DNA paired with thymine, in RNA paired with uracil. Adenine is one of the bases that form part of a nucleotide, the structures that are present in DNA chains. ( 4. A purine base, C5H5N5, one of the fundamental components of nucleic acids, as DNA, in which it forms a base pair with thymine, and RNA, in which it pairs with uracil. Symbol: A...

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/ˌadvenˈtiSH(ē)ə/ Noun 1. The outermost connective tissue covering of any organ, vessel, or other structure.( 2. The outermost layer of the wall of a blood vessel. (Google Dictionary) 3. The external covering of an organ or other structure, derived from connective tissue, especially the external covering of a blood vessel. ( 4. The outermost connective tissue covering of any organ, vessel, or other structure not covered by a serosa; instead, the covering is properly derived from without (i.e., from the surrounding connective tissue) and does not form an integral part of such organ or structure. ( Adjective: adventitial Synonym: tunica adventitia, membrana adventitia Word origin: Latin adventīcia, neuter plural of adventīcius...

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