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Chapter 12 Sensory Mechanisms. Types of receptors Somatic senses Special senses. Types of Receptors. Table 12.1 (1 of 2). Types of Receptors. Table 12.1 (2 of 2). Sensory Receptors in Skin. Hair. Epidermis. Merkel disks: light touch. Thermo-, light touch, and pain receptors.
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Chapter 12 Sensory Mechanisms • Types of receptors • Somatic senses • Special senses
Types of Receptors Table 12.1 (1 of 2)
Types of Receptors Table 12.1 (2 of 2)
Sensory Receptors in Skin Hair Epidermis Merkel disks:light touch Thermo-,light touch,and painreceptors Meissner’scorpuscle:light touch Dermis Ruffini endings:pressure Free nerveendings:sensechangingpositionof hairs Paciniancorpuscle:deep pressureand high-frequencyvibration Subcutaneouslayer Modified and encapsulatednerve endings Free nerveendings Figure 12.1
Special Senses- Taste • Taste buds • Chemoreceptors that bind with dissolved substances • Taste categories • Sweet • Salty • Sour • Bitter • Umami
Locations and Structure of the Receptors for Taste Figure 12.5d
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
Olfactory Receptors and the Mucus-Producing Olfactory Glands Figure 12.6
Hearing • Mechanoreceptors detect sound waves
Structure of the Human Ear Figure 12.9
Structures and Functions of the Ear Table 12.3
Structures and Function of the Cochlea Figure 12.10
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
Sensing Head Position and Acceleration Figure 12.13a–c
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
Structure of the Eye Sclera Choroid Canal ofSchlemm Retina Fovea Iris Opticdisk Lens Pupil Opticnerve Cornea Aqueoushumor Vitreoushumor Ciliarymuscle Figure 12.14
Parts of the Eye and Their Function Table 12.4
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
Examples of Abnormal Vision Figure 12.16a
Examples of Abnormal Vision Figure 12.16b
Examples of Abnormal Vision Figure 12.16c
Examples of Abnormal Vision Figure 12.16d
Structure of the Retina Figure 12.17
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
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