Begegnungen mit der Natur 6, Arbeitsheft

17 Neurobiologie How about using English – Structure and function of the eye Schulbuch Seite 66–67 O Complete the text by using the illustration above: Light enters the eye, passing first through the and the , which is watery. Next, the light passes through the flexible . It is a transparent structure, held in place by a ring of fibres called the . The is located in front of the . It is the coloured part of the eye. In the centre, there is a hole called the . Its size determines the amount of light which is allowed to enter the eye. After passing the , which is jelly, the light reaches the internal lining at the back of the eye, the . There, millions of light-sensitive cells are located. If light falls on these cells, they send out nervous impulses which travel in nerve fibres, through the , to the brain and so give rise to the sensation of sight. Accommodation When the contract, the go slack and the lens gets a smaller diameter and becomes thicker. Now the lens bends the light rays more – it is focusing light from nearer objects. When the relax, the lens gets slight. Now it bends light rays less, which is more effective when the viewer looks at more distant objects. eyebrow eye muscle sclera choroid retina yellow spot blind spot optic nerve vitreous humour ciliary muscle suspensory ligaments lid lid eye lashes lens pupil cornea iris aqueous humour Nur zu Prüfzwecken – Eigentum des Verlags öbv