2.- OUR SENSES 1.- Sight and hearing A) The sense of sight You use the sense of sight to distinguish the shape, colour, size and distance of objects. The eyes are the organs of sight. Eyelids, eyebrows and eyelashes protect the eyes. First, light passes through the cornea and then through the pupil that is a hole in the centre of the iris. The iris is a coloured ring. Behind the iris is the lens that helps you to focus. At the back of the eye, the retina captures the light and the optic nerve takes the information to the brain. B) The sense of hearing You use the sense of hearing to distinguish sounds. The ears are the sense organs of hearing and have three parts: the outer ear, middle ear and the inner ear. The pinna captures the sound that travels through the ear canal to the ear drum, which vibrates with the sound. The small bones move when the eardrum vibrates. The cochlea captures the sound vibrations and the auditory nerve takes the information to the brain.
2.- Touch, smell and taste. A) The sense of tousch. You use the sense of touch to identify characteristics of objects (rough, smooth, hard or soft, cold or hot‌) The skin is the organ of touch and has a lot of touch receptors which send the information to the brain. B) The sense of smell You use the sense of smell to distinguish smells and the nose is the sense organ of smell, The smell enters the nose through the nostrils and reach the olfactory epithelium inside the nasal cavity. The epithelium has smell receptors which send the information to the brain trough the olfactory nerve. c) The sense of taste You use the sense of taste to distinguish different flavours (sweet, salty, sour and bitter). The tongue is the organ of taste and is covered with taste buds which send the information to the brain through the nerves.
3.- Looking after your senses Good hygiene and protection are the two basic ways to look after your senses. A) Looking after your eyes
Don’t touch your eyes with dirty hands. Read or study with enough light. Protect your eyes with sunglasses or goggles in the swimming pool. Visit your doctor.
B) Looking after your ears
Wash your ears daily. Don´t put objects in your ears. Avoid noisy sounds. Visit yur doctor.