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Fundamentals of Anatomy & Physiology
SIXTH EDITION
Frederic H. M
artini
PowerPoint® Lecture Slide Presentation prepared by Dr. Kathleen A. Ireland, Biology Instructor, Seabury Hall, Maui, Hawaii
Chapter 17, part 1The Special Senses
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Learning Objectives
• Describe the sensory organs of smell, and trace the olfactory pathways to their destination in the brain.
• Identify the accessory and internal structures of the eye, and explain their function.
• Explain how light stimulates the production of nerve impulses, and trace the visual pathways to their destination in the brain.
• Describe the structures of the external and middle ear and explain how they function.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Learning Objectives
• Describe the parts of the inner ear and their roles in equilibrium and hearing.
• Trace the pathways for the sensations of equilibrium and hearing to their destinations in the brain.
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SECTION 17-1 Olfaction
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• Contain olfactory epithelium with olfactory receptors, supporting cells, basal cells• Olfactory receptors are modified neurons
• Surfaces are coated with secretions from olfactory glands
• Olfactory reception involved detecting dissolved chemicals as they interact with odorant binding proteins
Olfactory organs
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Figure 17.1 The Olfactory Organs
Figure 17.1a, b
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• Olfactory pathways• No synapse in the thalamus for arriving
information• Olfactory discrimination
• Can distinguish thousands of chemical stimuli• CNS interprets smells by pattern of receptor activity
• Olfactory receptor population shows considerable turnover
• Number of receptors declines with age
Olfaction
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SECTION 17-2 Gustation
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• Clustered in taste buds• Associated with lingual papillae
Taste receptors
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• Contain basal cells which appear to be stem cells
• Gustatory cells extend taste hairs through a narrow taste pore
Taste buds
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Figure 17.2 Gustatory Reception
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• Taste buds are monitored by cranial nerves• Synapse within the solitary nucleus of
the medulla oblongata• Then on to the thalamus and the primary
sensory cortex
Gustatory pathways
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• Primary taste sensations• Sweet, sour, salty, bitter• Receptors also exist for umami and
water• Taste sensitivity shows significant
individual differences, some of which are inherited
• The number of taste buds declines with age
Gustatory discrimination
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SECTION 17-3 Vision
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• Eyelids (palpebrae) separated by the palpebral fissue
• Eyelashes• Tarsal glands• Lacrimal apparatus
Accessory structures of the eye
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Figure 17.3 Eternal Features and Accessory Structures of the Eye
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external structures of the eye
• Conjunctiva covers most of eye• Cornea is transparent anterior portion
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Lacrimal apparatus
• Secretions from the lacrimal gland contain lysozyme
• Tears form in the lacrimal glands, wash across the eye and collect in the lacrimal lake
• Pass through the lacrimal punctae, lacrimal canaliculi, lacrimal sac and nasolacrimal duct
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The eye
• Three layers• Outer fibrous tunic
• Sclera, cornea, limbus• Middle vascular tunic
• Iris, ciliary body, choroid• Inner nervous tunic
• Retina
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Figure 17.4 The Sectional Anatomy of the Eye
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internal structures of the eye
• Ciliary body• Ciliary muscles and ciliary processes,
which attach to suspensory ligaments of lens
• Retina• Outer pigmented portion• Inner neural part
• Rods and cones
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Figure 17.4 The Sectional Anatomy of the Eye
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Figure 17.5 The Pupillary Muscles