Skin innervation

Published on October 7, 2014   27 min
0:00
Welcome to this presentation on skin innervation. My name is Martin Schmelz. I'm a neurophysiologist, and having worked mainly on pain and itch.
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In this presentation, we will first focus on structure and sensory function in healthy skin and then switch to skin innervation changes that happen in disease, such as loss of innervation for polyneuropathy and increased innervation that may be found in chronic itch and pain. And finally, we will also touch upon neuronal function beyond sensory tasks.
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When we regard innervation of healthy skin, the most abundant nerve fibers are small nerve fibers with free nerve endings that innervate the dermis, and are particularly dense in the epidermis. In contrast, these thick nerve fibers have specific sensory endings such as the Pacinian corpuscles and the Meissner corpuscles, located in the dermis.
1:09
The myelinated fibers are low threshold mechanosensitive fibers that are important to detect touch and texture. They can be differentiated into superficial and deeply located ones, with the superficial ones having small innervation territories and deep ones, large innervation territories. Merkel and Ruffini endings are slowly adapting, meaning that they encode chronic stimuli, whereas Meissner receptors and Pacinian corpuscles are rapidly adapting, such that they are particularly sensitive to phasic simulation.