Visual system Structure The eye, especially the retina

Visual system

Structure The eye, especially the retina The optic nerve The optic chiasma The optic tract The lateral geniculate body The optic radiation The visual cortex The visual association cortex. Different species are able to see different parts of the light spectrum; for example, bees can see into the ultraviolet, while pit vipers can accurately target prey with their pit organs, which are sensitive to infrared radiation.

Eye structure Parts of eye that response for vision: Cornea Pupil Lens Hyaloid canal Vitreous humour Macula of retina Retina Optic disc

Lens The crystalline lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina. The lens, by changing shape, functions to change the focal distance of the eye so that it can focus on objects at various distances, thus allowing a sharp real image of the object of interest to be formed on the retina. This adjustment of the lens is known as accommodation. It is similar to the focusing of a photographic camera via movement of its lenses.

Hyaloid canal Hyaloid canal is a small transparent canal running through the vitreous body from the optical nerve disc to the lens; in the fetus it contains a prolongation of the central artery of the retina, the hyaloid artery. Other names: Cloquet's canal, Stilling's canal. The function of the canal is to provide an adjustable reservoir of mobile liquid which may be easily and rapidly displaced backwards in positive accommodation, forwards in negative accommodation.