| natural products | Naturally occurring compounds that are end products of secondary metabolism; often, they are unique compounds for particular organisms or classes of organisms. (05 Mar 2000) |
|---|---|
| natural selection | The hypothesis that genotype environment interactions occurring at the phenotypic level lead to differential reproductive success of individuals and hence to modification of the gene pool of a population. (18 Nov 1997) |
| immunity, natural | The capacity of a normal organism to remain unaffected by microorganisms and their toxins. It results from non-specific mechanisms such as genetic endowment, naturally occurring antiviral and bactericidal substances, phagocytosis, and constitutional factors such as body temperature, oxygen tension, and age. (12 Dec 1998) |
| killer cells, natural | Cells responsible for spontaneous cytotoxicity of a variety of tumour cells without prior immunization. These natural killer cells are found in non-immune humans and experimental animals and are thought by some to be the same as killer cells (killing by antibody-dependent cell cytotoxicity), but they can also kill in the absence of antibody. (12 Dec 1998) |
| accessory organs of the eye | The eyelids, with lashes and eyebrows, lacrimal apparatus, conjunctival sac, and extrinsic muscles of the eyeball. Synonym: organa oculi accessoria, accessory organs, accessory visual apparatus, adnexa oculi, appendages of eye. (05 Mar 2000) |
| accommodation of eye | The increase in thickness and convexity of the eye's lens in order to focus the image of an external object upon the retina. (05 Mar 2000) |
| amaurotic cat's eye | A yellow reflex from the pupil in cases of retinoblastoma or pseudoglioma. (05 Mar 2000) |
| anterior chamber of eye | The space between the cornea anteriorly and the iris/pupil posteriorly, filled with a watery fluid (aqueous humor) and communicating through the pupil with the posterior chamber. Synonym: camera anterior bulbi, camera oculi anterior, camera oculi major. (05 Mar 2000) |
| anterior eye segment | That part of the eyeball anterior to the lens. (12 Dec 1998) |
| aphakic eye | The eye from which the lens is absent. (05 Mar 2000) |
| appendages of eye | The eyelids, with lashes and eyebrows, lacrimal apparatus, conjunctival sac, and extrinsic muscles of the eyeball. Synonym: organa oculi accessoria, accessory organs, accessory visual apparatus, adnexa oculi, appendages of eye. (05 Mar 2000) |
| artificial eye | A curved disk of opaque glass or plastic, containing an imitation iris and pupil in the centre, inserted beneath the eyelids and supported by the orbital contents after evisceration or enucleation; it may be ready-made (stock) or custom-made. (05 Mar 2000) |
| bird's-eye | <botany> A plant with a small bright flower, as the Adonis or pheasant's eye, the mealy primrose (Primula farinosa), and species of Veronica, Geranium, etc. Source: Websters Dictionary (01 Mar 1998) |
| black eye | Ecchymosis of the lids and their surroundings. (05 Mar 2000) |
| bleary eye | Sore, runny, watery eye with an associated lackluster appearance and, by extension, dimness of vision. (05 Mar 2000) |