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This chapter discusses the structural basis and the specific molecules involved in the interactions between the skin and different portions of the nervous system.
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The peripheral nervous system provides essential information to the rest of body during injury of “danger signals” such as parasites, UV radiation, toxins, allergens, pH changes, or “stress”. This information can be modulated at various levels including the brain, spinal cord, dorsal root ganglia (DRG), peripheral sensory nerve endings, autonomic nerves and neurons, etc; and through specialized structures like Pacini bodies or specialized cells such as Merkel cells. This closely woven group of structures and their molecules are ultimately and critically involved in normal cutaneous biology and skin diseases (eTable 102-0.1). In conjunction with the spinal cord and the brain, peripheral sensory nerves have afferent functions; their endings detect physical stimuli such as touch, heat or cold, and chemical mediators into the skin from nerve endings and also have efferent functions in the skin. (eFig. 102-0.1). These sensory nerves critically contribute to skin development before birth and to protection and homeostasis after birth. In addition, autonomic nerves modulate both physiological and pathophysiological functions as part of the stress response to external or endogenous stimuli, and form a vital link communicating with the vascular, endocrine, and immune systems (eTable 102-0.1).
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