Chapter 16.5, Problem 16AYLO

Summary Introduction

To discuss:

How light absorption generates an optic nerve signal.

Introduction:

The perception of items that are present in the surroundings is termed as sight or vision. This perception occurs by means of reflection or emission of light from those objects. The retina, the neural component, is one of the principle components of the eyeball. It consists of three cell layers that are composed of ganglion cells, bipolar cells, and photoreceptor cells. The photoreceptor cells are involved in the absorption of light and produce an electrical or chemical signal. These cells are of three kinds, namely cones, rods, and some ganglion cells. These cone and rod cells generate visual images and are related to ependymal cells present in the brain. Photopsin and rhodopsin is the visual pigment present in a cone cell and rod cell, respectively. Cone cells are responsible for photopic vision (day vision) and trichromatic vision (color vision), and rod cells are responsible for scotopic vision (night vision).