Sclera in lobe-finned fishes, various reptiles, and birds. The ring has disappeared in many groups, including living amphibians, some reptiles and fish, and all mammals. The eyes of all non-human primates are dark with small, barely visible sclera. The collagen of the sclera is continuous with the cornea. From outer to innermost, the four layers of the sclera are: The sclera is opaque due to the irregularity of the Type I collagen fibers, as opposed to the near-uniform thickness and parallel arrangement of the corneal collagen. Moreover, the cornea bears more mucopolysaccharide (a carbohydrate that has among its repeating units a
Catholic theology of the body God in his image. This is considered important even today, as the existence of a soul is the basis for much Church teachings on the human body, in areas such as abortion. Ambrose of Milan and Augustine of Hippo applied these views in their teachings on the human body, virginity and celibacy. Thomas Aquinas developed a systematic view, which dominated Church teachings and ecumenical councils including Vatican II. All recent popes contributed from different angles to the theology of the body. Current issues include the dignity of the body in light of its divine origin and destination, its eventual resurrection;