Sebaceous gland glands are in the areola that surrounds the nipple in the female breast. These glands secrete an oily fluid that lubricates the nipple, and also secrete volatile compounds that are thought to serve as an olfactory stimulus for the newborn. During pregnancy and lactation these glands, also called Montgomery's glands, become enlarged. Meibomian glands, in the eyelids, secrete a form of sebum called meibum onto the eye, that slows the evaporation of tears. It also serves to create an airtight seal when the eyes are closed and its lipid quality also prevents the eyelids from sticking together. The meibomian glands
Sealant despite not having great strength, convey a number of properties. They seal top structures to the substrate, and are particularly effective in waterproofing processes by keeping moisture out (or in) the components in which they are used. They can provide thermal and acoustical insulation, and may serve as fire barriers. They may have electrical properties, as well. Sealants can also be used for simple smoothing or filling. They are often called upon to perform several of these functions at once. A caulking sealant has three basic functions: It fills a gap between two or more substrates; it forms a barrier