Human eye Human eye The human eye is an organ which reacts to light and pressure. As a sense organ, the mammalian eye allows vision. Human eyes help to provide a three dimensional, moving image, normally coloured in daylight. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth. The human eye can differentiate between about 10 million colors and is possibly capable of detecting a single photon. Similar to the eyes of other mammals, the human eye's non-image-forming photosensitive ganglion cells in the retina receive light signals which affect adjustment
Induced stem cells form whole embryos from the remaining part. This meant that the cells can change their differentiation pathway. In 1924 Spemann and Mangold demonstrated the key importance of cell–cell inductions during animal development. The reversible transformation of cells of one differentiated cell type to another is called metaplasia. This transition can be a part of the normal maturation process, or caused by an inducement. One example is the transformation of iris cells to lens cells in the process of maturation and transformation of retinal pigment epithelium cells into the neural retina during regeneration in adult newt eyes. This process allows the