Sclera pass. The thickness of the sclera varies from 1mm at the posterior pole to 0.3 mm just behind the rectus muscle insertions. The sclera's blood vessels are mainly on the surface. Along with the vessels of the conjunctiva (which is a thin layer covering the sclera), those in the episclera render the inflamed eye bright red. In many vertebrates, the sclera is reinforced with plates of cartilage or bone, together forming a circular structure called the sclerotic ring. In primitive fish, this ring consists of four plates, but the number is lower in many living ray-finned fishes, and much higher
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