PHED-2506EL Lecture Notes - Lecture 12: Peripheral Nervous System, Sensory Neuron, Special Senses
14 Dec 2018
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Lecture 12: the peripheral nervous system part 1. Pns provides links to and from the external environment. Consists of all neural structures outside brain and spinal cord that can be broken down into four parts: sensory receptor, transmission lines: nerves and their structure and repair, motor endings and motor activity, reflex activity. Sensory receptors: specialized to respond to changes in environment (stimuli: activation results in graded potentials that trigger nerve impulses. Awareness of stimulus (sensation) and interpretation of meaning of stimulus (perception) occur in the brain. Three ways to classify receptors: type of stimulus, body location, structural complexity. Classification of stimulus type: mechanoreceptors respond to touch, pressure, vibration and stretch, thermoreceptors sensitive to changes in temperature, photoreceptors respond to light energy, chemoreceptors respond to chemicals, nociceptors sensitive to pain-causing stimuli. Classification by location: exteroceptors, respond to stimuli arising outside body, found near the body surface, receptors in skin for touch, pressure, pain and temperature, most special sense organs.
