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Unformatted text preview: 15: The Special Senses Objectives 1. Describe the structure and function of accessory eye structures, eye layers, the lens, and humors of the eye. 2. Outline the causes and consequences of cataracts and glaucoma. 3. Trace the pathway of light through the eye to the retina, and explain how light is focused for distant and close vision. 4. Outline the causes and consequences of astigmatism, myopia, hyperopia, and presbyopia. 5. Describe the events involved in the stimulation of photoreceptors by light, and compare and contrast the roles of rods and cones in vision. 6. Compare and contrast light and dark adaptation. 7. Trace the visual pathway to the visual cortex, and briefly describe the steps in visual processing. 8. Describe the location, structure, and afferent pathways of taste and smell receptors, and explain how these receptors are activated. 9. Describe the structure and general function of the outer, middle, and internal ears. 10. Describe the sound conduction pathway to the fluids of the internal ear, and follow the auditory pathway from the spiral organ (of Corti) to the temporal cortex. 11. Explain how the balance organs of the semicircular canals and the vestibule help maintain dynamic and static equilibrium. I. The Eye and Vision (pp. 548569; Figs. 15.115.20) [If it's bold, it's particularly gold!] A. Introduction Most animals have a way to sense light, from the primitive light-sensitive eyespots in flatworms, to the compound eyes of insects and the camera eye [using a lens] of vertebrates, including humans. While vision is our dominant sense, with some 70% of our body's sensory receptors found in our eyes, they are not the "perfect adaptation" that is sometimes claimed. More about that later... B. Accessory Structures of the Eye 1. Eyebrows are short, coarse hairs overlying the supraorbital margins of the eye that shade the eyes and keep perspiration out. 2. Eyelids (palpebrae), eyelashes, and their associated glands help to protect the eye from physical danger as well as from drying out. The tarsal glands [Meibomian glands] produce an oily secretion for lubrication and retention of tears; "dry eyes" are associated with dysfunction of these glands and infections are called a chalazion. 3. Conjunctiva is a transparent mucous membrane that lines the eyelids and the whites of the eyes. The conjunctiva produces a lubricating mucus that prevents the eye from drying out. Inflammation of the conjunctiva is called conjunctivitis while pinkeye is a bacterial or viral infection of this structure....
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This note was uploaded on 01/09/2012 for the course BIO 242 taught by Professor Jimellinger during the Spring '12 term at Bellevue College.
- Spring '12