When someone becomes excited, their pupils can dilate to up to four times their original size. Conversely, an angry, negative mood causes the pupils to contract to what are commonly known as 'beady little eyes' or 'snake eyes'. Lighter eyes can look more attractive because it's easier to see the dilation taking place.
The term papilla (plural: papillae) generally means a nipple-like structure, and may refer to: Mammary papilla, or nipple. Amphibian papilla and basal papilla, part of the inner ear of the frog. Interdental papilla, part of the gingiva between teeth.
The radula is a special structure used by many mollusks to scrape food off rocks, to feed off of plants or create depressions in rocks that the mollusk uses for habitat. The radula has many rows of tiny teeth that are replaced as they wear down. Each row of teeth consist of marginal teeth, one or more lateral teeth and a median tooth. One animal that has a radula is the common periwinkle, which uses its radula to scrape algae off rocks for food. The limpet is a marine invertebrate that uses its radula to create a home by boring a shallow hole into a rock. 1  List. 2  Article. 3  Article. 4  Article. 5  Article. 6  Article. 7  Article. 8  Article.