adaptation /ad·ap·ta·tion/ (ad″ap-ta´shun)
adaptation
adaptation,
adaptation
1. the adjustment of an organism to its environment, or the process by which it enhances such fitness.
2. the normal adjustment of the eye to variations in intensity of light.
3. the decline in the frequency of firing of a neuron, particularly of a receptor, under conditions of constant stimulation.
4. in 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.
5. in microbiology, the adjustment of bacterial physiology to a new environment.
color adaptation
1. changes in visual perception of color with prolonged stimulation.
2. adjustment of vision to degree of brightness or color tone of illumination.
dark adaptation adaptation of the eye to vision in the dark or in reduced illumination.
genetic adaptation the natural selection of the progeny of a mutant better adapted to a new environment.
light adaptation adaptation of the eye to vision in the sunlight or in bright illumination (photopia), with reduction in the concentration of the photosensitive pigments of the eye.
phenotypic adaptation a change in the properties of an organism in response to genetic mutation or to a change in the environment.
ad·ap·ta·tion ( d p-t  sh n)n. 1. The acquisition of modifications in an organism that enable it to adjust to life in a new environment. 2. An advantageous change in the function or constitution of an organ or tissue to meet new physiological conditions. 3. Adjustment of the pupil and retina to varying degrees of illumination. 4. A property of certain receptors through which they become less responsive or cease to respond to repeated or continued stimuli of constant intensity. 5. The fitting, condensing, or contouring of a restorative dental material to a tooth or cast. 6. The dynamic process in which the behavior and physiological mechanisms of an individual continually change to adjust to variations in living conditions. |
adaptation
[ad′aptā′shən]
Etymology: L, adaptatio, act of adapting
a change or response to stress of any kind, such as inflammation of the nasal mucosa in infectious rhinitis or increased crying in a frightened child. Adaptation may be normal, self-protective, and developmental, as when a child learns to talk; it may be all-encompassing, creating further stress, as in polycythemia, which occurs naturally at high altitudes to provide more oxygen-carrying erythrocytes but may also lead to thrombosis, venous congestion, or edema. The degree and nature of adaptation shown by a patient are evaluated regularly by the nurse. They constitute a measure of the effectiveness of nursing care, the course of the disease, and the ability of the patient to cope with stress. Compare accommodation.
adaptation,
n 1. an alteration that an organ or organism undergoes to adjust to its environment.
2. a close approximation of a tissue flap, an appliance, or a restorative material to natural tissue.
3. an accurate adjustment of a band or a shell to a tooth.
4. a condition in reflex activity marked by a decline in the frequency of impulses when sensory stimuli are repeated several times.
2. a close approximation of a tissue flap, an appliance, or a restorative material to natural tissue.
3. an accurate adjustment of a band or a shell to a tooth.
4. a condition in reflex activity marked by a decline in the frequency of impulses when sensory stimuli are repeated several times.
adaptation, instrument,
n the process of manually adjusting and positioning the functional end, edge, or surface of a dental instrument for safe and effective use according to its purpose and relative to the shape of the tooth.
adaptation
1. adjustment of the pupil to light, constricting with increased light intensity, dilating with decreased intensity.
2. any anatomical, physiological, developmental or behavioral adjustment to the environment of an organism which enhances its chances of leaving descendants. The ability of animals to adapt to a limited supply of drinking water and to high or low environmental temperatures is an important aspect of animal husbandry. The selection of animals which are capable of a high level of such adaptation has made it possible to improve the productivity of herds and flocks in some countries. See also general adaptation syndrome.
3. the process by which organisms are modified so as to improve their chances of survival in an environment.
dark adaptation
adaptation of the eye to vision in the dark or in reduced illumination.
light adaptation
adaptation of the eye to vision in sunlight or in bright illumination (photopia), with reduction in the concentration of the photosensitive pigments of the eye.
negative adaptation
see habituation.
adaptation rate
the rate at which afferent sensory receptors discharge into their afferent axons. The rates differ between different types of receptors. For example, there are slow adaptors which signal the more persistent changes such as steady pressure. See also receptor adaptation (below).
receptor adaptation
sensory receptors vary in their individual response to stimuli, the response declining after an initial period of rapid response. The rate at which different kinds of receptors change these responses is the adaptation rate (see above).
adaptation
1. Process by which a sensory organ (e.g. the eye) adjusts to its environment (e.g. to luminance, colour or contact lens wear).
2. The reduction in sensitivity to continuous sensory stimulation. The neurophysiological correlate corresponds to a decrease in the frequency of action potentials fired by a neuron, despite a stimulus of constant magnitude. Visual adaptation is prevented from occurring by the continuous involuntary movements of the eyes. See fixation movements; action potential; stabilized retinal image.
chromatic adaptation Apparent changes in hue and saturation after prolonged exposure to a field of a specific colour.
dark adaptation Adjustment of the eye (particularly regeneration of visual pigments and dilatation of the pupil), such that, after observation in the dark, the sensitivity to light is greatly increased, i.e. the threshold response to light is decreased. This is a much slower process than light adaptation. Older people usually take longer to adapt to darkness and only reach a higher threshold than young people. See adaptometer; hemeralopia; visual pigment; duplicity theory.
light adaptation Adjustment of the eye (particularly bleaching of visual pigments and constriction of the pupil), such that, after observation of a bright field, the sensitivity to light is diminished, i.e. the threshold of luminance is increased. See duplicity theory.
prism adaptation See vergence adaptation.
sensory adaptation Mechanism by which the visual system adjusts to avoid confusion and diplopia of the perceptual impression due to an abnormal motor condition (e.g. strabismus).
vergence adaptation A process by which the eyes return to their condition of habitual heterophoria or orthophoria after a heterophoria has been induced by prisms (prism adaptation) in front of one or both eyes (as, for example, when lens centration does not coincide with the interpupillary distance), or by spherical lenses, or due to changes in the orbital contents with increasing age. This adaptation process may be related to the phenomenon of orthophorization. People who have symptomatic binocular vision anomalies do not, or only partially, show vergence adaptation to prisms. Vergence adaptation decreases with increasing age.
chromatic adaptation Apparent changes in hue and saturation after prolonged exposure to a field of a specific colour.
dark adaptation Adjustment of the eye (particularly regeneration of visual pigments and dilatation of the pupil), such that, after observation in the dark, the sensitivity to light is greatly increased, i.e. the threshold response to light is decreased. This is a much slower process than light adaptation. Older people usually take longer to adapt to darkness and only reach a higher threshold than young people. See adaptometer; hemeralopia; visual pigment; duplicity theory.
light adaptation Adjustment of the eye (particularly bleaching of visual pigments and constriction of the pupil), such that, after observation of a bright field, the sensitivity to light is diminished, i.e. the threshold of luminance is increased. See duplicity theory.
prism adaptation See vergence adaptation.
sensory adaptation Mechanism by which the visual system adjusts to avoid confusion and diplopia of the perceptual impression due to an abnormal motor condition (e.g. strabismus).
vergence adaptation A process by which the eyes return to their condition of habitual heterophoria or orthophoria after a heterophoria has been induced by prisms (prism adaptation) in front of one or both eyes (as, for example, when lens centration does not coincide with the interpupillary distance), or by spherical lenses, or due to changes in the orbital contents with increasing age. This adaptation process may be related to the phenomenon of orthophorization. People who have symptomatic binocular vision anomalies do not, or only partially, show vergence adaptation to prisms. Vergence adaptation decreases with increasing age.
adaptation
Opthalmology The ability of the eye to adjust to variations in light intensity Psychology The fitting of behavior to the environment by modifying one's impulses, emotions, or attitudes. See Social adaptation.
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