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
The Human Body (TV series) The Human Body (TV series) The Human Body is a seven-part documentary series, first shown on 20 May 1998 on BBC One and presented by medical scientist Robert Winston. A co-production between the BBC and The Learning Channel, the series looks at the mechanics and emotions of the human body from birth to death. The series was nominated for numerous awards, winning several, including three BAFTA awards, four RTS awards and a Peabody Award. Described as the BBC's "first major TV series on human biology", it took over two years to make and aimed to be the definitive set of