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Chapter 10, part A. Sensory Physiology. 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. General Properties of Sensory Systems. Stimulus Internal External
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Chapter 10, part A Sensory Physiology
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
General Properties of Sensory Systems • Stimulus • Internal • External • Energy source • Receptors • Sense organs • Transducer • Afferent pathway • CNS integration
General Properties of Sensory Systems Figure 10-4: Sensory pathways
Sensory Receptor Types • Structural types: • Simple receptors • Complex neural • Special senses • Types according to the nature of stimulus • Chemoreceptors • Mechanoreceptors • Thermoreceptors • Photoreceptors
Sensory Receptor Types Figure 10-1: Sensory receptors
Special Senses – External Stimuli • Vision • Hearing • Taste • Smell • Equilibrium
Special Senses – External Stimuli Figure 10-4: Sensory pathways
Somatic Senses – Internal Stimuli • Touch • Temperature • Pain • Itch • Proprioception • Pathway 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
Somatic Pathways Figure 10-9: Sensory pathways cross the body’s midline
Sensory Modality • Location • Lateral inhibition • Receptive field • Intensity • Duration • Tonic receptors • Phasic receptors • Adaptation
Sensory Modality Figure 10-3: Two-point discrimination
Sensory Modality Figure 10-6: Lateral inhibition
Touch (pressure) • Mechanoreceptors • Free nerve endings • Pacinian corpuscles • Ruffini corpuscles • Merkel receptors • Meisaner's corpuscles • Barroreceptors
Touch (pressure) Figure 10-11: Touch-pressure receptors
Temperature • Free nerve endings • Cold receptors • Warm receptors • Pain receptors • Sensory coding: • Intensity • Duration
Temperature Figure 10-7: Sensory coding for stimulus intensity and duration
Pain and Itching • Nociceptors • Reflexive path • Itch • Fast pain • Slow pain
Pain and Itching Figure 10-12: The gate control theory of pain modulation
Referred Pain Figure 10-13: Referred pain