53.2 MB (2.5 MB compressed)
3474 x 5352 pixels
29.5 x 45.2 cm ⏐ 11.6 x 17.8 in (300dpi)
MICHAEL W. DAVIDSON / SCIENCE PHOTO LIBRARY MICHAEL W. DAVIDSON / SCIENCE PHOTO LIBRARY
Vitamin A. polarised light micrograph of crystals of vitamin A (retinal). Vitamin A is required by the body for normal growth, for the formation of bones & teeth, for cell structure and for protecting the linings of the respiratory, digestive & urinary tracts against infection. Vit- amin A is absorbed by the body as retinol. This is found in liver, fish liver oils, egg yolk & dairy produce. Carotene is converted into vitamin A in the body, & is found in green vegetables & fruit. Vitamin A deficiency is rare in developed countri- es. The first symptom of deficiency is night blin- dness, with dryness & inflammation of the eyes & stunted growth in children. Magnification: unknown.
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