part of part of contributes to morphology of protects camera-type eye organ part eyelid A fold of skin that covers and protects part of the eyeball. Examples: upper eyelid, lower eyelid, nictitating membrane BTO:0002241 Consider adding 'eye surface', like MA EHDAA2:0000487 EHDAA:9037 EMAPA:17829 EV:0100338 FMA divides this into skin, fascia, conjunctiva FMA:54437 GAID:72 In humans the upper and lower eyelid consists of the following layers, starting anteriorly: (1) skin, (2) a layer of subcutaneous connective tissue, (3) a layer of striated muscle fibres of the orbicularis muscle, (4) a layer of submuscular connective tissue, (5) a fibrous layer, including the tarsal plates, (6) a layer of smooth muscle, (7) the palpebral conjunctiva. MA:0000268 MESH:D005143 OpenCyc:Mx4rvVi4m5wpEbGdrcN5Y29ycA UBERON:0001711 UMLS:C0015426 VHOG:0000016 blephara blepharic blepharon eye lid palpebra palpebrae palpebral uberon ectoderm-derived structure ocular surface region