THIRD EDITION HUMAN PHYSIOLOGY AN INTEGRATED APPROACH Dee

THIRD EDITION HUMAN PHYSIOLOGY AN INTEGRATED APPROACH Dee Unglaub Silverthorn, Ph. D. Chapter 10 Sensory Physiology Power. Point® Lecture Slide Presentation by Dr. Howard D. Booth, Professor of Biology, Eastern Michigan University Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

About this Chapter • What are the senses • How sensory systems work • Body sensors and homeostatic maintenance • Sensing the external environment • Mechanisms and pathways to perception Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

General Properties of Sensory Systems • Stimulus • Internal • External • Energy source • Receptors • Sense organs • Transducer • Afferent pathway • CNS integration Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

The Human Brain Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

General Properties of Sensory Systems Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -4: Sensory pathways

Sensory Receptor Types • Simple receptors • Complex neural • Special senses • Chemoreceptors • Mechanoreceptors • Thermoreceptors • Photoreceptors Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Sensory Receptor Types Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -1: Sensory receptors

The Cerebral Cortex • Three kinds of functional areas • Motor areas • Sensory areas • Association areas Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Functional and Structural Areas of the Cerebral Cortex Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Functional and Structural Areas of the Cerebral Cortex Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 13. 11 b

Special Senses – External Stimuli • Vision • Hearing • Taste • Smell • Equilibrium Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Special Senses – External Stimuli Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -4: Sensory pathways

Homunculus Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Sensory Areas – Sensory Homunculus Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 13. 10

Motor Homunculus Copyright © 2005 Pearson Education, Inc. , Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 13. 10

Somatic Senses – Internal Stimuli • Touch • Temperature • Pain • Itch • Proprioception • Pathway Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -10: The somatosensory cortex

Somatic Pathways • Receptor • Threshold • Action potential • Sensory neurons • Primary – medulla • Secondary – thalamus • Tertiary – cortex • Integration • Receptive field • Multiple levels Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Somatic Pathways Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -9: Sensory pathways cross the body’s midline

Sensory Modality • Tonic receptors: Adapt slowly • Phasic receptors: Adapt quickly Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Sensory Modality Figure 10 -3: Two-point discrimination Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Touch (pressure) • Mechanoreceptors • Free nerve endings • Pacinian corpuscles • Ruffini corpuscles • Merkel receptors • Meissner's corpuscles • Baroreceptors Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Touch (pressure) Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -11: Touch-pressure receptors

Temperature • Free nerve endings • Cold receptors • Warm receptors • Pain receptors • Sensory coding: • Intensity • Duration Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Temperature Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -7: Sensory coding for stimulus intensity and duration

Pain and Itching • Nocioceptors • Reflexive path • Itch • Fast pain • Slow pain Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Pathways of Itch from Skin to Brain. Yosipovitch G, Bernhard JD. N Engl J Med 2013; 368: 1625 -1634. Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Gate Control Theory of Pain Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -12: The gate control theory of pain modulation

Pain • Ischemia • Other visceral pain • Modulation • Thalamus • Gate control • Magnification • Analgesic drugs • Aspirin • Opiates Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Referred Pain Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -13: Referred pain

Olfactor: Sense of Smell • Olfactory cell • Chemoreceptor- Humans have about 400 different types of odorant receptors, Mice 1200 • Olfactory cilia • Olfactory bulb • Olfactory nerve • CNS integration • Amygdala • Hippocampus • Olfactory Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Odor Receptors • According to an analysis of data derived from the human genome project, humans have approximately 400 functional genes coding for olfactory receptors • Most odors activate more than one type of odor receptor • The # of combinations and permutations of olfactory receptors is almost limitless thus the olfactory receptor system is capable of detecting and distinguishing between a practically infinite number of odorant molecules Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Olfactor: Sense of Smell Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -14 a, b: ANATOMY SUMMARY: Olfaction

Olfactor: Sense of Smell Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -14 c: ANATOMY SUMMARY: Olfaction

Taste: Chemoreceptors • 5 Tastes • Taste buds • Taste cells • Mechanism • Transduction • Integration • Thalamus • Gustatory cortex • "Specific hunger" Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -16: Summary of taste transduction

Taste Receptor Physiology • In the last 15 years, advancements in molecular biology have unraveled the proteins that function as taste receptors. There at least five taste qualities that are consciously perceived, sweet, sour, salty, bitter, and umami. Of these five, sour and salty are mediated by ion channels, whereas the perception of sweet, umami, and bitter tastes is mediated by G protein-coupled receptors (GPCRs). These taste GPCRs belong to the TAS 1 R and TAS 2 R gene families. It has been suspected for more than a century that the gut can sense the chemical composition of foods. The description of multiple taste GPCRs in gastrointestinal (GI) cells suggests that there are nutrient-sensing mechanisms in the GI tract, oral, gastric, and intestinal mucosa. Oral sensing seems to mainly influence food discrimination and nutrient appetite, while post-oral chemosensors may relate to nutrient utilization and inhibition of appetite. Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Hearing: Mechanoreceptors • Sound waves • Conduction • Air • Bone • Fluid • Membranes • To hair cell Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Hearing: Mechanoreceptors Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -19: Sound transmission through the ear

Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Hearing: Hair Cell Transduction • Fluid wave moves • Tectoral membrane • Steriocilia move • Ion channels open • Depolarization • NT release • Sensory nerve AP Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Hearing: Hair Cell Transduction Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -20: The cochlea

Hearing: Hair Cell Transduction Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -21: Signal transduction in hair cells

Hearing: Integration and Problems • Pitch • Intensity • Localization • Integration • Medulla • Thalamus • Auditory cortex • Deafness • Conductive • Sensorineural Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -5: Localization of sound

Localization of Sound Underwater • Hearing threshold and the ability to localize sound sources are reduced underwater. The resonance frequency of the external ear is lowered when the external ear canal is filled with water, and the impedance-matching ability of the middle ear is significantly reduced due to elevation of the ambient pressure, the water-mass load on the tympanic membrane, and the addition of a fluid-air interface during submersion. Sound lateralization on land is largely explained by the mechanisms of intensity differences and temporal or phase differences. During submersion, these differences are largely lost due to the increase in underwater sound velocity and cancellation of the head's acoustic shadow effect because of the similarity between the impedance of the skull and the surrounding water. Bone conduction plays the main role in underwater hearing. Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Hearing: Integration and Problems Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -22: Sensory coding for pitch

Equilibrium: Mechanoreceptor • Body balance • Body position • Body movement • Propioceptors • Vision • Vestibular apparatus Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Equilibrium: Mechanoreceptor • Integration • Medulla • Cerebellum • Thalamus • Cortex Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -26: Central nervous system pathways for equilibrium

Equilibrium: Vestibular Apparatus • Otolith organs: sense linear acceleration • Gravity • Calcite crystals • Hair cells • Semicircular canals: sense rotational acceleration • Endolymph Fluid moves which stimulates Each Crista which consists of: Cupula Embedded Hair cells: activate CN VIII Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Semicircular Canals of the Vestibular Apparatus • Have Posterior, Horizontal and Superior Semicircular Canals • They sense Rotational Acceleration in various directions • The Cristae within the Ampula (enlarged chamber at the end of each canal) are the sensory receptors • Endolymph moves the gelatinous cupula with the hair cells embedded in it and stimulates vestibulocochlear nerve (CN VIII) Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Equilibrium: Vestibular Apparatus Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -23 a, b: ANATOMY SUMMARY: Vestibular Apparatus

Otolith Organs of the Vestibular Apparatus • Otolith Organs of the Utricle and Saccule Sense Linear Acceleration and Head Position • They are arranged horizontally (Utricle-if head tips back gravity causes othliths to slide) and vertically (Saccule-senses vertical forces such as an elevator dropping) • Macula are the sensory receptors of the utricle and saccule • Otoliths are crystals that move in response to gravitational forces Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Equilibrium: Vestibular Apparatus Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -23 c, d: ANATOMY SUMMARY: Vestibular Apparatus

Vision: Photoreceptors • Reflected light translated into mental image • Pupil limits light, lens focuses light • Retinal rods and cones are photoreceptors Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -36: Photoreceptors in the fovea

Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Cataract Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Retina (Right Eye) Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Retina (Left Eye) Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Hypercholesterolemia • Accumulations of lipids leak from surrounding capillaries and microaneuryisms, they may form a circinate pattern. Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Hypertension Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Proliferative diabetic retinopathy Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Panretinal laser photocoagulation Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Photoreception and Local Integration • Rods – night vision • Cones – color & details • Bipolar & ganglion cells converge, integrate APs Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Photoreception and Local Integration Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -35: ANATOMY SUMMARY: The Retina

Retina: More Detail • Rod cells: monochromatic • Cone cells: red, green, & blue • Discs: visual pigments • Pigmented epithelium • Melanin granules • Prevents reflection Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Retina: More Detail Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -38: Photoreceptors: rods and cones

Vision: Integration of Signals to Perception • Bipolar • Ganglion • Movement • Color • Optic nerve • Optic chiasm • Optic tract • Thalamus • Visual cortex Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 10 -29 b, c: Neural pathways for vision and the papillary reflex

Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Summary • Sensory pathway: receptor, sensory neuron(s) & CNS • Somatic senses: touch, temperature, pain & proprioception communicate body information to CNS • Special senses: taste, smell, hearing, equilibrium, & vision • Outside conditions for CNS integration into perception • Receptors transduce mechanical, chemical or photon energy into GPs then to APs Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings