Secretions from different glands feed into the same spinnerets, like a soft ice cream machine that can make chocolate or vanilla. A spinneret consists of hundreds of microscope tubes coming from the silk glands. The glands are called major ampullate and minor ampullate, and the number of each varies in different species. The terms minor ampullate and major ampullate are also used to describe certain silks and silk proteins. Although researchers are just now working out the precise chemical structures of silk proteins, silks have long been named according to their macroscopic functions.
Bridgeline silk is the first strand, on which an entire web is constructed.
Trapline silk, extending from the center of a web, vibrates when prey makes contact, telling the spider that dinner has arrived. The focus of much research is dragline silk, known to consist of two types of major ampullate proteins. This particular thread always extends from the spider to the web. Should the animal encounter danger, it scurries back to the safety of the web on the dragline. Dragline silk also makes up the spokes of a web.