TAILIEUCHUNG - Lecture Human anatomy and physiology - Chapter 13: The peripheral nervous system and reflex activity (part a)
In this chapter, you will learn to: Define peripheral nervous system and list its components; classify general sensory receptors by structure, stimulus detected, and body location; outline the events that lead to sensation and perception; describe receptor and generator potentials and sensory adaptation; describe the main aspects of sensory perception. | 13 The Peripheral Nervous System and Reflex Activity: Part A Peripheral Nervous System (PNS) All neural structures outside the brain Sensory receptors Peripheral nerves and associated ganglia Motor endings Figure Central nervous system (CNS) Peripheral nervous system (PNS) Motor (efferent) division Sensory (afferent) division Somatic nervous system Autonomic nervous system (ANS) Sympathetic division Parasympathetic division Sensory Receptors Specialized to respond to changes in their environment (stimuli) Activation results in graded potentials that trigger nerve impulses Sensation (awareness of stimulus) and perception (interpretation of the meaning of the stimulus) occur in the brain Classification of Receptors Based on: Stimulus type Location Structural complexity Classification by Stimulus Type Mechanoreceptors—respond to touch, pressure, vibration, stretch, and itch Thermoreceptors—sensitive to changes in temperature Photoreceptors—respond to light energy (., retina) Chemoreceptors—respond to chemicals (., smell, taste, changes in blood chemistry) Nociceptors—sensitive to pain-causing stimuli (. extreme heat or cold, excessive pressure, inflammatory chemicals) Classification by Location Exteroceptors Respond to stimuli arising outside the body Receptors in the skin for touch, pressure, pain, and temperature Most special sense organs Classification by Location Interoceptors (visceroceptors) Respond to stimuli arising in internal viscera and blood vessels Sensitive to chemical changes, tissue stretch, and temperature changes Classification by Location Proprioceptors Respond to stretch in skeletal muscles, tendons, joints, ligaments, and connective tissue coverings of bones and muscles Inform the brain of one’s movements Classification by Structural Complexity Complex receptors (special sense organs) Vision, hearing, equilibrium, smell, and taste (Chapter 15) Simple receptors for general senses: Tactile sensations (touch, pressure, stretch, .
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