Retina The retina in its anatomical origin - is a part of the central nervous system that carried far away on the periphery. It is light-receiving s

Inner layer of the eye (retina, crystalline lens, vitreous body, visual pathways and nerve)

Retina

The retina in its anatomical origin — is a part of the central nervous system that carried far away on the periphery. It is light-receiving structure of the eye that converts light stimulus into nerve impulses, carrying out the primary processing of the visual signal.

Crystalline lens

The crystalline lens (diagram 167) — is a transparent disk-shaped elastic body suspended with special bundles to the ciliary body. It is similar to a lenticular lens of 10 mm in diameter. The crystalline lens contains no blood vessels and nerves — it feeds the intercellular fluid.

Vitreous body

Vitreous body (diagram 167) is located behind the crystalline lens and fills most of the eye cavity. This is a transparent gelatinous mass without blood vessels and nerves. Vitreous body is important eyes "filler"; it keeps its spherical shape and ensures the supply of light to the retina.

Diagram 167. Structure of the eye: 1 — retina; 2 — vitreous; 3 — the visual axis; 4 — the optical axis; 5 — the central fossa; 6 — yellow spot; 7 — the optic nerve; 8 — the sclera; 9 — choroid; 10 — ciliary body; 11 — rear camera; 12 — front camera; 13 — lens; 14 — cornea; 15 — iris; 16 — ciliary muscle; 17 — conjunctiva

Visual pathways

The axons of the nerve cells inner layer in the retina form a sensitive optic nerve, which has over a million nerve fibers (diagram 167). He gets out of the eye and passes through a hole in the skull cavity. Taken from http://worldofschool.org

Visual nerve

The visual nerve is a peripheral part of the visual pathways. They also include optic chiasm and optic tract. The central part of the visual pathways is formed by the front colliculus of the midbrain and visual thalamic nuclei. In these structures occurs an analysis of visual signals. One part of the fibers of the optic nerve, which starts from the outer half of the retina of each eye passes to the same named (right, left) occipital areas of cortex — visual centers. The same fibers that originate from the inner half of the retina of each eye intersect at the location of the optic chiasm and go to the opposite side, approaching the oppositely named areas of the occipital cortex, i.e. the optic nerve fibers of the left — to the right, right — to the left. As a result, visual images, which are formed in the centers of the cerebral cortex, are the consequence of information income from both eyes.

Categories:
Questions:
  • Explain the interrelation of the crystalline lens structure and functions.

  • Prove the relationship between the structure and functions of the vitreous body.