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 interior surface of the rumen forms numerous papillae. The papillae can be long and foliated or short and pointed. They are up to 6mm in length. Animals fed on rough grass or in the dry season have longer papillae, whereas animals fed on digestible feed or in the wet season have shorter papillae (1-2mm in length).