Human Eye and Colour Vision - Case Study Example

Each receptor has a specific pigment to absorb a specific wavelength of light. The transmembrane proteins are found in these cells. This protein is also known as Opsin. It has a prosthetic group called retinal. It is a derivative of Vitamin A. This is used by all four receptors. Night-blindness and color-blindness are results of the deficiency of Vitamin A in any or all type of receptors. The retina consists of bipolar and ganglion cells. These cells form the path from cones and rods to the brain and transfer the responses.

Ganglionic cells are always very active. The response to different wavelength is due to the cone cells present in the human eye. Rods and cones are absent at the blind spot of the eye. This is the place where no image is formed hence called Blindspot. Light enters our eyes through the lens at the front of the eye and is focused onto the retina inside the back of the eye. The retina is covered with millions of light-sensitive cells which pass on signals to the brain via the optic nerve. Vision is based on the visual stimulus.

The rod cells help differentiating darkness, light and detecting motion and movements. These are active in low light or darkness. The cone cells are sensitive to the colour differences. Each eye has around 120 million rod cells and six million cone cells. The receptive field of the eye consists of a retinal ganglion cell. These cells receive inputs from one to thousands of photoreceptors. These receptors are arranged in a center-suthe round array with on centers and off perimeters or vice versa.

Each eye has nearly 126 million of photoreceptors. The cone cells are concentrated towards the centre of the retina. This is the area where more light falls. These long, medium and small to the new cells are interspersed in the retina. There are several layers of these cells. These layers support the image processing in the brain. The photopigments in the cone cells are adjusted for a specific band of the spectrum of light. These detect the wavelengths of light. Wavelengths of light belong to certain predominant colour bands i.e. red, green and blue.

  The light which falls on retina is most of the time consist of overlapping wavelengths of light.