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Medical Term:

vitamin A


  1. any ß-ionone derivative, except provitamin A carotenoids, possessing qualitatively the biologic activity of retinol; deficiency interferes with the production and resynthesis of rhodopsin, thereby causing night blindness, and produces a keratinizing metaplasia of epithelial cells that may result in xerophthalmia, keratosis, susceptibility to infections, and retarded growth;
  2. the original vitamin A, now known as retinol.

Synonym(s): axerophthol

© Copyright 2017 Wolters Kluwer. All Rights Reserved. Review Date: Sep 19, 2016.