>> As a child you probably learned about the five senses of sight, smell, taste, sound and touch. This chapter on the special senses also covers five senses; vision, smell, taste, hearing and balance. As you learned in the chapter on the peripheral nervous system, the sensation of touch is experienced through the simple receptors of the general senses. In contrast the five special senses, which consist of the other four commonly referenced senses, plus balance or equilibrium. Each have special sensory receptors that are housed in organs and structures located in the head. As a healthcare professional it's very important for you to understand the anatomy and physiology of these organs and structures so that you can evaluate and treat diseases that affect them. For example, in order to watch for signs and symptoms of common diseases affecting the eye in your patients, you will need to know that the eye contains internal chambers and fluids. Normally fluids within the eye form and drain at the same rate; however, if the draining of fluid is blocked and backs up, pressure within the eye may increase. Glaucoma is a condition where the pressures inside the eye increase to dangerous levels compressing the retina and optic nerve. Unless the condition is detected early the eventual result is blindness. Late signs of glaucoma include seeing halos around lights and blurred vision. Having a solid understanding of the anatomy and physiology of the eye will allow you to detect signs of glaucoma and other diseases affecting your patient's vision and conduct relevant exams and treatment.