Tarsus (eyelids) is a groove in the inner surface of each eyelid. Along the inner margin of the tarsus are modified sebaceous glands known as tarsal glands (or meibomian glands), aligned vertically within the tarsi: 30 to 40 glands in the upper lid, and 20 to 30 in the lower lid, which secrete a lipid-rich product which helps keep the lacrimal secretions or tears from evaporating too quickly, thus keeping the eye moist. Tarsus (eyelids) The tarsi (tarsal plates) are two comparatively thick, elongated plates of dense connective tissue, about in length; one is found in each eyelid, and contributes to its
Sealant sealants is that sealants typically have lower strength and higher elongation than adhesives do. When sealants are used between substrates having different thermal coefficients of expansion or differing elongation under stress, they need to have adequate flexibility and elongation. Sealants generally contain inert filler material and are usually formulated with an elastomer to give the required flexibility and elongation. They usually have a paste consistency to allow filling of gaps between substrates. Low shrinkage after application is often required. Many adhesive technologies can be formulated into sealants. Sealant Sealant is a substance used to block the passage of fluids through