Question

describe vision from the special senses

Answer 1

VISION:Vision is a special sense in human body. The initiation of vision is started in the photoreceptor cell in the eye that is rod and cone cell in the retina. The retina has ten layers layer of pigmented epithelium, layer of rod and cone cells, external limiting membrane, outer nuclear layer, outer plexiform layer, inner nuclear layer, inner plexiform layer, ganglion cell layer, nerve fibre and inner limiting membrane. At first the image of an object fall on retinal, then the photosensitive ganglion cell in the retinal structure helps in the transmission of visual signal to the visual cortex. The signal from this ganglionic cell pass through the optic nerve (nerve fibre layer) to the brain. The image is also processed in the image processing cells of the retina and the visual pathway. The image fall on the retina is actually a inverted image due to the presence of transperant, biconvex lens in the eye. This lens invert the original image and fall on the retina. Retina then processed the image and sent the signal via optic nerve to the visual cortex. The optic nerve from the left eye crosses the optic nerve from the right eye and form optic chiasma. This is the reason by which the right eye sent sigal to the left visual cortex and left eye sent signal to the right visual cortex. Arter reaching the visual cortex the signal is perceived according to their colour, form, contrast. Visual signal are also transmitted to the posterior parietal cortex for the perception of motions, depth of the object. The inferior temporal cortex is also received signal from the visual pathway for the identification of colour, form of the object.

This way the signal from the object fall on retina through lens, cornea, and form inverted image after that the signal transmitted to the visual cortex and others area of the brain for the sensation of the object and ultimately form a original image of the object in our mind to sens it. This is the mechanism by which body visualized the object in the environment through vision which is a special sense in our body.