Thursday, August 8, 2019

Exploring Human Eyes Conversion of Visible Light Into Neural Activity Essay

Exploring Human Eyes Conversion of Visible Light Into Neural Activity and Conveying of Visual Information into Visual Cortex - Essay Example Light rays first come in contact with cornea which helps in maintaining the anterior chamber of the eye. The light rays travel via small hole known as a pupil , it contains iris muscles in its surrounding which later pass on to the lens, it aids in converging the beam of light to focus the object depending on the distance. (SK277 Course Team, 2004, p.63) This phenomenon is also known as accommodation reflex. Human eye comprises of two chambers namely the anterior chamber and posterior chamber. ... The diameter of the aperture is enhanced by the activity of radial muscle, whereas as the diameter is decreased when circular muscles act. The image is finally produced on the retina which is made up of several distinct layers, it also possesses receptors for light known as photoreceptors. (SK277 Course Team, 2004, p.63) Before the formation of the image, the light has to pass through the several layers and receptors present in the retina. These photoreceptors can be categorized as rods and cones. Both rods and cons have a distinct function. Data gathered from the rods play a vital role in night vision.These receptors are highly sensitive to the low level of light and are unable to give the details of the object at night. Due to this fact, we can see objects more clearly during daytime as compared to the night. Whereas, cons are responsible for viewing the object during the daytime. The photopigment that is present within rods and cons are capable of absorbing light in them. These pi gments are 125 million in numbers and are made up of a protein known as opsin; they also carry a chemical named as retinene (SK277 Course Team, 2004, p.64) The role of this photoreceptor is to convert the energy generated from the light into biochemical signals via electrical activity which in the end reaches retinal ganglion cells. These cells take the information to the brain for final processing. Now axons present in retinal ganglion cells leads to the production of the optic nerve and optic chiasm, it has overlapping fibers forming optic tract, they end up as a lateral geniculate nucleus in the area of the thalamus. (SK277 Course Team, 2004, p.68) Later, the signals are transferred to the primary visual cortex and secondary visual area. The processing of visual

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