Chapter 15 The Senses Lecture Outline PDF

Chapter 15 The Senses Lecture Outline Organization of the Nervous System (Figure 14.2) Access the text alternative for these images Organization of the Nervous System (Figure 14.2) Access the text alternative for these images The Two Divisions of th...

Chapter 15 The Senses Lecture Outline Organization of the Nervous System (Figure 14.2) Access the text alternative for these images Organization of the Nervous System (Figure 14.2) Access the text alternative for these images The Two Divisions of the Nervous System (Figure 14.1) Access the text alternative for these images  Overview of Sensory Receptors and Sensations 2 Sensory receptor—converts signals from the environment, called stimuli, into nerve impulses. 5 ©2020 McGraw-Hill Education  The Structure of Sensory Neurons, Interneurons, and Motor Neurons (Figure 14.3) Access the text alternative for these images 6 ©2020 McGraw-Hill Education (photos) (a): ©McGraw-Hill Education/Dr. Dennis Emery, Dept. of Zoology and Genetics, Iowa State University, photographer; (b): ©David M. Phillips/Science Source  Overview of Sensory Receptors and Sensations 2 Sensory receptor—converts signals from the environment, called stimuli, into nerve impulses. This conversion is called sensory transduction. Exteroceptors—sensory receptors that detect stimuli from outside the body. For example, taste, smell, vision, hearing, and equilibrium. Continuously send messages to the CNS. 7 ©2020 McGraw-Hill Education  Overview of Sensory Receptors and Sensations 3 Sensory receptor, continued. Interoceptors—receive stimuli from inside the body. For example, baroreceptors (pressoreceptors) respond to changes in blood pressure. For example, osmoreceptors monitor water-salt balance. Stretch receptors Are directly involved in homeostasis 8 ©2020 McGraw-Hill Education  Types of Sensory Receptors 1 Sensory receptors are classified into four categories: chemoreceptors, photoreceptors, mechanoreceptors, and thermoreceptors. Chemoreceptors—respond to chemical substances. For example, taste, smell, and blood pH. 9 ©2020 McGraw-Hill Education  Types of Sensory Receptors 2 Sensory receptors, continued. Photoreceptors—respond to light. Mechanoreceptors—stimulated by mechanical forces. For example, hearing, balance, touch, blood pressure, stretch receptors, proprioceptors. Thermoreceptors—stimulated by changes in temperature; regulate body temperature. For example, in the hypothalamus and skin. 10 ©2020 McGraw-Hill Education  Exteroceptors (Table 15.1) Table 15.1 Exteroceptors. Sensory Receptor Stimulus Category Sense Sensory Organ Taste cells Chemicals Chemoreceptor Taste Taste bud Olfactory cells Chemicals Chemoreceptor Smell Olfactory epithelium Rod cells and cone cells Light rays Photoreceptor Vision Eye in retina Hair cells in spiral organ Sound Mechanoreceptor Hearing Ear of the inner ear waves Hair cells in semicircular Motion Mechanoreceptor Rotational Ear canals of the inner ear equilibrium Hair cells in vestibule of Gravity Mechanoreceptor Gravitational Ear the inner ear equilibrium 11 ©2020 McGraw-Hill Education  How Sensation Occurs 1 Sensation—the conscious perception of stimuli. Occurs in the cerebral cortex. The sensation that results depends on which part of the brain receives the nerve signals. Before sensory receptors initiate nerve signals, they also carry out integration. 12 ©2020 McGraw-Hill Education  The Role of the CNS and PNS in Sensation and Sensory Perception (Figure 15.1) Access the text alternative for these images 13 ©2020 McGraw-Hill Education  How Sensation Occurs 2 Sensation, continued. One type of integration is sensory adaptation—a decrease in response to a stimulus over time. For example, smelling an odor at first and later not being aware of it. Sensory receptors send fewer impulses to the brain. 14 ©2020 McGraw-Hill Education  Pain Receptors 1 When tissues are damaged by toxins or mechanical, thermal, or electrical stimuli, they release chemicals called prostaglandins, which bind to nociceptors. Aspirin and ibuprofen reduce pain by inhibiting the enzymes that synthesize prostaglandins. 15 ©2020 McGraw-Hill Education  Exteroceptors (Table 15.1) Table 15.1 Exteroceptors. Sensory Receptor Stimulus Category Sense Sensory Organ Taste cells Chemicals Chemoreceptor Taste Taste bud Olfactory cells Chemicals Chemoreceptor Smell Olfactory epithelium Rod cells and cone cells Light rays Photoreceptor Vision Eye in retina Hair cells in spiral organ Sound Mechanoreceptor Hearing Ear of the inner ear waves Hair cells in semicircular Motion Mechanoreceptor Rotational Ear canals of the inner ear equilibrium Hair cells in vestibule of Gravity Mechanoreceptor Gravitational Ear the inner ear equilibrium 16 ©2020 McGraw-Hill Education  Sense of Smell Sense of smell. 80% of what we perceive as “taste” actually is due to the sense of smell. Can’t taste well with a stuffed-up nose. Olfactory cells—found in the olfactory epithelia in the roof of the nasal cavity. Modified neurons. Each has olfactory cilia, which bear receptor proteins for odor molecules. 17 ©2020 McGraw-Hill Education  The Sense of Smell (Figure 15.5) Access the text alternative for these images 18 ©2020 McGraw-Hill Education  Anatomy and Physiology of the Ear 1 The ear. Has three divisions: outer, middle, and inner. 19 ©2020 McGraw-Hill Education  The Three Divisions of the Human Ear (Figure 15.12) stirrup anvil hammer Access the text alternative for these images 20 ©2020 McGraw-Hill Education  Anatomy and Physiology of the Ear 1 The ear. Has three divisions: outer, middle, and inner. Outer ear—consists of the pinna and the auditory canal. Auditory canal—lined with hairs and modified sweat glands that secrete earwax. Guards against the entrance of foreign matter. 21 ©2020 McGraw-Hill Education  Anatomy and Physiology of the Ear 2 The ear, continued. Middle ear—begins at the tympanic membrane (eardrum) and ends at a bony wall containing two small openings covered by membranes. The openings are the oval window and round window. Ossicles—three small bones found here. Malleus (hammer), which touches the tympanic membrane. Incus (anvil). Stapes (stirrup), which touches the oval window. 22 ©2020 McGraw-Hill Education  The Three Divisions of the Human Ear (Figure 15.12) stirrup anvil hammer Access the text alternative for these images 23 ©2020 McGraw-Hill Education  The Three Divisions of the Human Ear (Figure 15.12) stirrup anvil hammer Access the text alternative for these images 24 ©2020 McGraw-Hill Education  The Three Divisions of the Human Ear (Figure 15.12) stirrup anvil hammer Access the text alternative for these images 25 ©2020 McGraw-Hill Education  The Three Divisions of the Human Ear (Figure 15.12) stirrup anvil hammer Access the text alternative for these images 26 ©2020 McGraw-Hill Education  The Three Divisions of the Human Ear (Figure 15.12) stirrup anvil hammer Access the text alternative for these images 27 ©2020 McGraw-Hill Education  The Three Divisions of the Human Ear (Figure 15.12) stirrup anvil hammer Access the text alternative for these images 28 ©2020 McGraw-Hill Education  Auditory Pathway to the Brain Sound waves strike the tympanic membrane; it vibrates https://onlinetonegenerator.com/ This causes vibrations of the hammer, anvil, and then the stirrup The stirrup strikes the oval window, causing it to vibrate This passes the pressure to the fluid within the cochlea 29 ©2020 McGraw-Hill Education  The Three Divisions of the Human Ear (Figure 15.12) stirrup anvil hammer Access the text alternative for these images 30 ©2020 McGraw-Hill Education  The Cochlea 3 Cochlea Volume is a function of the amplitude (strength) of sound waves. Loud noises cause the fluid within the vestibular canal to exert more pressure and the basilar membrane to vibrate to a greater extent. The resulting increased stimulation is interpreted by the brain as volume. 31 ©2020 McGraw-Hill Education  How the Spiral Organ (Organ of Corti) Translates Sound Waves into Nerve Signals (Figure 15.13a,b) Access the text alternative for these images 32 ©2020 McGraw-Hill Education  How the Spiral Organ (Organ of Corti) Translates Sound Waves into Nerve Signals (Figure 15.13c,d) 33 ©2020 McGraw-Hill Education (photo): ©P. Motta/SPL/Science Source  Cochlear Implant https://ais.southampton.ac.uk/cochlear-implant/cochlear-implant-sound-like/ Access the text alternative for these images 34 ©2020 McGraw-Hill Education  Noises That Affect Hearing (Table 15.3) Table 15.3 Noises That Affect Hearing. Type of Noise Sound Level (Decibels) Effect Loud music in car, jet engine, Over 125 Beyond threshold of pain; shotgun, rock concert potential for hearing loss high Nightclub, thunderclap Over 120 Hearing loss likely Earbuds in external ear canal 110 to 120 Hearing loss likely Chain saw, pneumatic drill, 100 to 200 Regular exposure of more than 1 jackhammer, symphony orchestra, minute risks permanent hearing snowmobile, garbage truck, loss. cement mixer Farm tractor, newspaper press, 90 to 100 Fifteen minutes of unprotected subway, motorcycle exposure potentially harmful Lawn mower, food blender 85 to 90 Continuous daily exposure for more than 8 hour can cause hearing damage. Diesel truck, average city traffic 80 to 85 Annoying; constant exposure noise may cause hearing damage. 35 ©2020 McGraw-Hill Education  Noises That Affect Hearing (Table 15.3) Table 15.3 Noises That Affect Hearing. Type of Noise Sound Level (Decibels) Effect “Boom Baby car,” (screaming, crying jet engine, shotgun, actually) Over 120 125 Beyond threshold of pain; rock concert potential for hearing loss high Nightclub, thunderclap Over 120 Hearing loss likely Earbuds in external ear canal 110 to 120 Hearing loss likely Chain saw, pneumatic drill, 100 to 200 Regular exposure of more than 1 jackhammer, symphony orchestra, minute risks permanent hearing snowmobile, garbage truck, loss. cement mixer Farm tractor, newspaper press, 90 to 100 Fifteen minutes of unprotected subway, motorcycle exposure potentially harmful Lawn mower, food blender 85 to 90 Continuous daily exposure for more than 8 hour can cause hearing damage. Diesel truck, average city traffic 80 to 85 Annoying; constant exposure noise may cause hearing damage. 36 ©2020 McGraw-Hill Education  The Three Divisions of the Human Ear (Figure 15.12) stirrup anvil hammer Access the text alternative for these images 37 ©2020 McGraw-Hill Education  Balance Pathway 2 Rotational equilibrium. Semicircular canals As fluid within a semicircular canal flows over and displaces a cupula, the stereocilia of the hair cells bend. The vestibular nerve carries signals generated here to the brain. Appropriate motor output to various skeletal muscles corrects the body’s position in space as needed. 38 ©2020 McGraw-Hill Education  The Mechanoreceptors of the Inner Ear and the Sense of Balance (Figure 15.14a) Access the text alternative for these images 39 ©2020 McGraw-Hill Education  The Mechanoreceptors of the Inner Ear and the Sense of Balance (Figure 15.14b) Access the text alternative for these images 40 ©2020 McGraw-Hill Education