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 nerve endings Thermo-, light touch, and pain receptors Modified and encapsulated nerve endings Merkel disks: light touch Hair Free nerve endings: sense changing position of hairs Meissner’s corpuscle: light touch Pacinian corpuscle: deep pressure and high- frequency vibration Ruffini endings: pressure Epidermis Subcutaneous layer 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 Structures and Function of the Cochlea
Copyright © 2009 Pearson Education, Inc. 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
Copyright © 2009 Pearson Education, Inc. 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 Structure of the Eye Canal of Schlemm Iris Lens Pupil Cornea Aqueous humor Ciliary muscle Sclera Choroid Vitreous humor Retina Fovea Optic disk Optic nerve
Copyright © 2009 Pearson Education, Inc. Table 12.4 Parts of the Eye and Their Function
Copyright © 2009 Pearson Education, Inc. 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 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
Copyright © 2009 Pearson Education, Inc. 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