#mucous_membrane__mucosa  mucus-secreting membrane lining all body cavities or passages that communicate with the exterior
  supertype:  tissue_layer__membrane  a pliable sheet of tissue that covers or lines or connects organs or cells of animals
  subtype:  conjunctiva  a transparent membrane covering the eyeball and under surface of the eyelid
     subtype:  pinguecula  a slightly elevated elastic tissue deposit in the conjunctiva that may extend to the cornea but does not cover it
     subtype:  pterygium  a thickened triangular layer of conjunctiva extending from the nasal edge of the eye to the cornea; pterygia arise from irritation of the pinguecula
  subtype:  endometrium  the mucous membrane that lines the uterus; thickens under hormonal control and (if pregnancy does not occur) is shed in menstruation; if pregnancy occurs it is shed along with the placenta at parturition
  subtype:  hymen__maidenhead__virginal_membrane  a fold of tissue that partly covers the entrance to the vagina of a virgin
     subtype:  imperforate_hymen__imperforatehymen  hymen that is completely closed so that menstrual blood cannot flow out

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