These tears are rich in salts, lysozyme, and immunoglobulins. They protect the eyes from insects and dust particles. The eyelashes are hair-like outgrowth projecting from the eyelids. They protect the eyes from dust, insects, etc., by their reflection action. Eyelids and lashes:Įyelids are delicate layers of tissue that cover the eye. These help to prevent sweat, dust, and other waste from falling over the eye and the head.

These are arch-shaped ridges projecting from the frontal bone. These are the parts that help in the safety and smooth functioning of the eye. The retinal chamber is filled with vitreous humor. The point at which the nerves from the retina converge is called the optic spot. The light received from the lens is converted into a nerve impulse and carried backward as the optic nerve into the brain for further processing. The cones are color sensitive and recognize the colors. The rods are light-sensitive and recognize the dark and bright light. It consists of photosensitive cells, namely the rods and cones.

This retina is the only part of the eye that perceives the light and converts it into electrical energy. This neural coat of the eye is an essential part of the eye. This is the innermost layer of the eye made of nerve cells. When it constricts, it becomes thicker and when it dilates, it becomes thin.

It helps to focus the objects based on their distance and concentrate the refracted light onto the retina. The lens is a biconvex, transparent and elastic structure that can alter its shape. Light enters through the pupil and the size of the pupil is regulated by the iris.This iris separates the aqueous chamber into anterior and posterior chambers.Iris has a hole in its center called the pupil.Consists of the colored portion of the eye known as the iris.The choroid coat is the middle layer of the eyeball.Its front surface, the cornea, is transparent to let light enter the eye.Close when objects are placed near the eye: reflex arc Įxternal Structures of the Eye 1.The posterior lining of the eye contains photoreceptors.From 2 outgrowths of the brain that form the optic nerves & the optic cup:.Send information to brain directly via optic nerve.

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