H UMAN P HYSIOLOGY AN INTEGRATED APPROACH T H I R D E D I T I O N Chapter 10, part A Sensory Physiology

2 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

3 Stimulus Internal External Energy source Receptors Sense organs Transducer Afferent pathway CNS integration General Properties of Sensory Systems

4 Figure 10-4: Sensory pathways

5 Simple receptors Complex neural Special senses Chemoreceptors Mechanoreceptors Thermoreceptors Photoreceptors Sensory Receptor Types

6 Figure 10-1: Sensory receptors

7 Vision Hearing Taste Smell Equilibrium Special Senses – External Stimuli

8 Figure 10-4: Sensory pathways

9 Touch Temperature Pain Itch Proprioception Pathway Somatic Senses – Internal Stimuli Figure 10-10: The somatosensory cortex

10 Receptor Threshold Action potential Sensory neurons Primary – medulla Secondary – thalamus Tertiary – cortex Integration Receptive field Multiple levels Somatic Pathways

11 Somatic Pathways Figure 10-9: Sensory pathways cross the body’s midline

12 Location Lateral inhibition Receptive field Intensity Duration Tonic receptors Phasic receptors Adaptation Sensory Modality

13 Sensory Modality Figure 10-3: Two-point discrimination

14 Sensory Modality Figure 10-6: Lateral inhibition

15 Mechanoreceptors Free nerve endings Pacinian corpuscles Ruffini corpuscles Merkel receptors Meisaner's corpuscles Barroreceptors Touch (pressure)

16 Touch (pressure) Figure 10-11: Touch-pressure receptors

17 Free nerve endings Cold receptors Warm receptors Pain receptors Sensory coding: Intensity Duration Temperature

18 Temperature Figure 10-7: Sensory coding for stimulus intensity and duration

19 Nociceptors Reflexive path Itch Fast pain Slow pain Pain and Itching

20 Pain and Itching Figure 10-12: The gate control theory of pain modulation

H UMAN P HYSIOLOGY AN INTEGRATED APPROACH T H I R D E D I T I O N Chapter 10, part B Sensory Physiology

22 Ischemia Other visceral pain Modulation Thalamus Gate control Magnification Analgesic drugs Aspirin Opiates Referred Pain

23 Referred Pain Figure 10-13: Referred pain

24 Olfactory cell Chemoreceptor Olfactory cilia Olfactory bulb Olfactory nerve CNS integration Amygdala Hippocampus Olfactory Olfactor: Sense of Smell

25 Olfactor: Sense of Smell Figure 10-14a, b: ANATOMY SUMMARY: Olfaction

26 Olfactor: Sense of Smell Figure 10-14c: ANATOMY SUMMARY: Olfaction

27 5 Tastes Taste buds Taste cells Mechanism Transduction Integration Thalamus Gustatory cortex "Specific hunger" Taste: Chemoreceptors Figure 10-16: Summary of taste transduction

28 Sound waves Conduction Air Bone Fluid Membranes To hair cell Hearing: Mechanoreceptors

29 Hearing: Mechanoreceptors Figure 10-19: Sound transmission through the ear

30 Fluid wave moves Tectoral membrane Steriocilia move Ion channels open Depolarization NT release Sensory nerve AP Hearing: Hair Cell Transduction

31 Hearing: Hair Cell Transduction Figure 10-20: The cochlea

32 Hearing: Hair Cell Transduction Figure 10-21: Signal transduction in hair cells

33 Pitch Intensity Localization Integration Medulla Thalamus Auditory cortex Deafness Conductive Sensorineural Hearing: Integration and Problems Figure 10-5: Localization of sound

34 Hearing: Integration and Problems Figure 10-22: Sensory coding for pitch

H UMAN P HYSIOLOGY AN INTEGRATED APPROACH T H I R D E D I T I O N Chapter 10, part C Sensory Physiology

36 Body balance Body position Body movement Propioceptors Vision Vestibular apparatus Equilibrium: Mechanoreceptor

37 Integration Medulla Cerebellum Thalamus Cortex Equilibrium: Mechanoreceptor Figure 10-26: Central nervous system pathways for equilibrium

38 Otolith organs Gravity Calcite crystals Hair cells Semicircular canals Fluid moves Cristae Cupula Hair cells Equilibrium: Vestibular Apparatus

39 Equilibrium: Vestibular Apparatus Figure 10-23a, b: ANATOMY SUMMARY: Vestibular Apparatus

40 Equilibrium: Vestibular Apparatus Figure 10-23c, d: ANATOMY SUMMARY: Vestibular Apparatus

41 Reflected light translated into mental image Pupil limits light, lens focuses light Retinal rods and cones are photoreceptors Vision: Photoreceptors Figure 10-36: Photoreceptors in the fovea

42 Rods – night vision Cones – color & details Bipolar & ganglion cells converge, integrate APs Photoreception and Local Integration

43 Photoreception and Local Integration Figure 10-35: ANATOMY SUMMARY: The Retina

44 Rod cells: monochromatic Cone cells: red, green, & blue Discs: visual pigments Pigmented epithelium Melanin granules Prevents reflection Retina: More Detail

45 Retina: More Detail Figure 10-38: Photoreceptors: rods and cones

46 Photons "bleach" opsin, retinal released, cascade, Na + channel closes, K + opens, hyperpolarization Reduces NT release Phototransduction

47 Phototransduction Figure 10-40: Phototransduction in rods

48 Bipolar Ganglion Movement Color Optic nerve Optic chiasm Optic tract Thalamus Visual cortex Vision: Integration of Signals to Perception Figure 10-29b, c: Neural pathways for vision and the papillary reflex

49 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 Summary