Chapter 16.5, Problem 10AYLO

Summary Introduction

To discuss:

The structure and action of the pupillary constrictor and dilator; anatomy of their autonomic innervation; and the photo pupillary reflex.                                       

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, and these cell layers 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 and they are cones, rods, and some ganglion cells. These cone and rod cells generate visual images and these cells are related 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).