øyelokksstruktur

The eye's eyelid, known scientifically as the palpebra, is a complex structure that serves crucial protective and functional roles. It consists of several layers, starting with the skin on the outside. Beneath the skin is a layer of muscle, primarily the orbicularis oculi, which controls blinking and eyelid closure, and the levator palpebrae superioris, responsible for raising the upper eyelid. A thin sheet of connective tissue called the tarsal plate provides structural support to the eyelid. Embedded within the tarsal plate are the meibomian glands, which secrete an oily substance that lubricates the eye's surface and prevents rapid evaporation of tears. The inner lining of the eyelid is the conjunctiva, a transparent mucous membrane that also covers the front of the eyeball, contributing to moisture and protection. Eyelashes, located along the eyelid margin, act as a physical barrier against dust and debris. The intricate coordination of these components allows for rapid blinking, which spreads tears, cleans the eye, and protects it from sudden irritants. The upper and lower eyelids meet at the medial and lateral canthi, forming the corners of the eye.