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An introduction to skin and skin disease
Published in Rashmi Sarkar, Anupam Das, Sumit Sethi, Concise Dermatology, 2021
Recently, very fine nerve fibres have been identified in the epidermis, but most of the fibres run alongside the blood vessels in the dermal papillae and deeper in the dermis. There are several types of specialized sensory receptor in the upper dermis that detect particular sensations. Free nerve endings perceive touch, temperature, pain, and itch. Pacinian corpuscles respond to deep pressure and vibrations. Other sensory receptors include Golgi-Mazzoni corpuscles, Krause end bulbs, Meissner’s corpuscle (responding to dynamic pressure), Ruffini corpuscles (responding to stretching of the skin), and mucocutaneous end organs.
Comparative Anatomy, Physiology, and Biochemistry of Mammalian Skin
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
Pacinian corpuscles and Meissner corpuscles decrease in number with age.116,253 The corpuscles that remain are usually larger. The Krause end-bulbs are thought by some investigators to be a stage in the growth or degeneration cycle of peripheral nerves.116 Some investigators believe that Meissner’s corpuscles, Pacinian corpuscles, mucocutaneous end organs, the hair follicle network, and free nerve endings are the only type of sensory receptors that are present in the skin of mammals. All other structures that have been described are considered artifacts due to shrinking, compression, section thickness, or plane of sectioning.217,219,254
Homeostasis
Published in David Sturgeon, Introduction to Anatomy and Physiology for Healthcare Students, 2018
The final type of nerve ending found in the dermis are thermoreceptors which, as their name suggests, respond to changes in temperature. There are two types of thermoreceptor: hot and cold. Although both are found throughout the body, there are about four times as many cold receptors as there are hot. The parts of the body with the greatest concentrations are the face and ears which explains why they often feel cold before the rest of the body on a chilly winter’s day (unless or course you are wearing that item of 1970s chic – the knitted balaclava). Cold receptors (also known as Krause’s end bulbs) start to perceive cold when the surface of the skin reaches about 35°C (normal skin or shell temperature is about 36°C). Maximal rate of firing occurs at temperatures between about 20-30°C. As temperature declines further, firing becomes less frequent which explains why we experience numbness, particularly to our extremities (hand, feet and face). Hot receptors (Ruffini’s corpuscles), on the other hand, begin to respond when the temperature of the skin reaches about 30°C. Once it rises above about 45°C, pain receptors (nociceptors) will be activated to prevent tissue damage from occurring. Thermoreceptors can provide seemingly contradictory information, however, and you may have wondered why you sometimes feel cold when first standing under a hot shower. This is because cold receptors can also be activated by skin temperatures of about 45°C resulting in a brief sensation of cold followed by a prolonged sensation of heat (and possibly pain).
Quantitative sensory testing (QST) in the orofacial region of healthy Chinese: influence of site, gender and age
Published in Acta Odontologica Scandinavica, 2018
Yanting Wang, Xueyin Mo, Jinglu Zhang, Yuan Fan, Kelun Wang, Svensson Peter
Interestingly, the present study showed no significant differences in MDT or MPT between the younger and older groups. In the oral region, encapsulated sensory corpuscles such as Krause’s end-bulbs have been found in monkey fungiform papillae [35], but the influence of aging on these receptors has not been evaluated. Taguchi et al. also found that nociceptive behaviors in response to noxious levels of cold and heat were facilitated in aged animals, while mechanical sensitivity measured by von Frey hairs remained unchanged. These discrepancies between the changes in peripheral afferents and the behavioral outcomes might be explained by facilitatory changes in the central nervous system [36].