copyright © 2009 pearson education, inc. chapter 12 sensory mechanisms types of receptors somatic...
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Copyright © 2009 Pearson Education, Inc.
Chapter 12 Sensory Mechanisms
Types of receptors
Somatic senses
Special senses
Copyright © 2009 Pearson Education, Inc. Table 12.1 (1 of 2)
Types of Receptors
Copyright © 2009 Pearson Education, Inc. Table 12.1 (2 of 2)
Types of Receptors
Copyright © 2009 Pearson Education, Inc. Figure 12.1
Sensory Receptors in Skin
Free nerveendings
Thermo-,light touch,and painreceptors
Modified and encapsulatednerve endings
Merkel disks:light touch
Hair
Free nerveendings:sensechangingpositionof hairs
Meissner’scorpuscle:light touch
Paciniancorpuscle:deep pressureand high-frequencyvibration
Ruffini endings:pressure
Epidermis
Subcutaneouslayer
Dermis
Copyright © 2009 Pearson Education, Inc.
Special Senses- Taste
Taste buds Chemoreceptors that bind with dissolved
substances
Taste categories Sweet
Salty
Sour
Bitter
Umami
Copyright © 2009 Pearson Education, Inc. Figure 12.5d
Locations and Structure of the Receptors for Taste
Copyright © 2009 Pearson Education, Inc.
Smell
Olfactory receptor cells Chemoreceptors that bind with odorants
Correlation between taste and smell Chewed food releases chemicals that come
in contact with olfactory receptors
Copyright © 2009 Pearson Education, Inc. Figure 12.6
Olfactory Receptors and the Mucus-Producing Olfactory Glands
Copyright © 2009 Pearson Education, Inc.
Hearing
Mechanoreceptors detect sound waves
Copyright © 2009 Pearson Education, Inc. Figure 12.9
Structure of the Human Ear
Copyright © 2009 Pearson Education, Inc. Table 12.3
Structures and Functions of the Ear
Copyright © 2009 Pearson Education, Inc. Figure 12.10
Structures and Function of the Cochlea
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Balance: Inner Ear
Specialized structures of inner ear Vestibular apparatus
Three semicircular canals and vestibule
Sensing rotational movement Ampulla with mechanoreceptors in cupula
Sensing head rotation and acceleration Uticle and saccule in vestibule with otoliths
Copyright © 2009 Pearson Education, Inc. Figure 12.13a–c
Sensing Head Position and Acceleration
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Vision
Detecting and interpreting visual stimuli by converting light energy to nerve impulses and transmitting them to the brain
Structures Sclera and cornea
Aqueous humor, iris, lens
Vitreous humor, retina, optic nerve
Fovea centralis, optic disc
Copyright © 2009 Pearson Education, Inc. Figure 12.14
Structure of the Eye
Canal ofSchlemm
IrisLens
Pupil
Cornea
Aqueoushumor
Ciliarymuscle
ScleraChoroid
Vitreoushumor
RetinaFovea
Opticdisk
Opticnerve
Copyright © 2009 Pearson Education, Inc. Table 12.4
Parts of the Eye and Their Function
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Regulating Light and Focusing
Focusing (continued) Eye shape
Normal shape allows focusing at fovea
Myopia: eye longer, nearsighted
Hyperopia: eye shorter, farsighted
Astigmatism: irregularities in cornea or lens
Copyright © 2009 Pearson Education, Inc. Figure 12.16a
Examples of Abnormal Vision
Copyright © 2009 Pearson Education, Inc. Figure 12.16b
Examples of Abnormal Vision
Copyright © 2009 Pearson Education, Inc. Figure 12.16c
Examples of Abnormal Vision
Copyright © 2009 Pearson Education, Inc. Figure 12.16d
Examples of Abnormal Vision
Copyright © 2009 Pearson Education, Inc. Figure 12.17
Structure of the Retina
Copyright © 2009 Pearson Education, Inc.
Disorders of Sensory Mechanisms
Disorders of the ear Deafness
Nerve
Conduction
Otitis media
Inflammation of the middle ear
Ménière’s syndrome
Inner ear condition impairs hearing and balance
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Disorders of Sensory Mechanisms
Disorders of the eye Retinal detachment
Retina separates from choroid Cataracts
Lens becomes opaque Glaucoma
Pressure inside the eye rises Color blindness
Inability to distinguish the full range of colors