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Chapter 17, part 1. The Special Senses. 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. - PowerPoint PPT Presentation
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Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
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
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
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.
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
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
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
• 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
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 17.2
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
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 17.3a, b
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
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
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
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 17.4a, b
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
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 17.4c
Figure 17.4 The Sectional Anatomy of the Eye
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Figure 17.5 The Pupillary Muscles
