What Are Eye Cones?

A type of visual cell located in the retina. Because it can receive light stimulation and convert light energy into nerve impulses, it is also called photoreceptor. It consists of four parts: the outer segment, the inner segment, the cell body and the terminal leg. Its outer segment is conical, hence the name cone cell. Contains light-sensitive substances (rhodopsin). Under light stimulation, a series of photochemical changes and potential changes can occur in light-sensitive substances, causing cones to emit nerve impulses.

Cone cell

Also known as "photoreceptor cells". Located in the retina, it converts light stimuli into nerve impulses. Optic cells are composed of four parts: the outer segment, the inner segment, the soma, and the terminal leg. The soma is a swollen portion with a nucleus, which is equivalent to an axon at the end, and the dendrites at the inner and outer segments. The outer segment is the light-sensitive part of the visual cell. It has a sheet (or disc) structure formed by invading and folding of the cell membrane, which contains light-sensitive substances. The inner section is slightly thick and contains a large number of mitochondria, which is the most vigorous part of energy metabolism. The outer section is connected to the inner section. From the inner section there are 9 pairs of small cilia extending into the outer section, which play a role in transmitting excitement and material. Optic cells are divided into cone cells and rod cells. The human retina contains approximately 6 to 8 million cone cells and 120 million rod cells distributed in different parts of the retina. There are only cone cells and no rod cells in the central recess of the macula. Only at the edge of the fovea began to have rod cells, and further out, the number of rod cells gradually increased, and the number of cone cells gradually decreased. Visual cells contain light-sensitive substances. Under light stimulation, a series of photochemical changes and potential changes can occur, causing the visual cells to emit nerve impulses, which are transmitted to the bipolar cells via the end feet of the visual cells (cone or rod).
One of hereditary macular degeneration. Cone cell dystrophy mainly damages cone cells and is also accompanied by rod rod damage to varying degrees. The main symptoms are vision loss, acquired color vision abnormalities, and night blindness can also occur when rod cells are damaged. Fundus manifestations: The lesions mainly involve the macula. It may be normal at first, and then the central light reflection disappears. The macular area is blue-gray with gold foil-like reflection, and the retinal pigment epithelium atrophy. Fundus fluorescein angiography: bullseye-like or diffuse depigmentation (window-like defect) in the macula. ERG manifests as a loss of photopic response than scotopic response.


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