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
Development of the human cerebral cortex during neurogenesis at mouse E10.5 to E12.5. Of the six layers found within the cortex, "layer 1 is the most superficial layer of the cortex...composed of Cajal-Retzius neurons and pyramidal cortex cells." This layer is unique in the aspect that these cells migrate to the outer edge of the cortex opposed to the migration experienced by the other 5 layers. Layer one is also characterized by expression of reelin, transcription factor T-box brain 1, and cortical migratory neuronal marker. The second and third layers, or the External Granular layer and External Pyramidal layer respectively, are formed around mouse E13.5 to