As surfaces sensitivity is defined as the detection of stimuli lying in the skin receptors . These receptors are divided into mechano , thermo and pain receptors , with the help of which pressure , touch and vibrations as well as temperature and pain can be felt . Surface sensitivity is part of exteroception . The mechanical part of the surface sensitivity is called the sense of touch , whereby the passive perception is called tactile (from Latin tangere , 'to touch') and the active perception is called haptic .
From a systematic point of view, surface sensitivity consists of a protopathic component (temperature and pain - mainly protecting the body and therefore "fast", but above all undifferentiated in the spatial sense) and an epicritical component ( tactile acuity , requires a little more time).
In humans and other mammals, tactile perception is made possible by mechanoreceptors in the skin . These include the so-called Merkel cells , Ruffini , Meissner and Vater-Pacini bodies , the information of which is transmitted to the CNS via class Aβ nerve fibers .
Protopathic sensations (temperature and pain) come from thermoreceptors and pain receptors . They are mediated by afferents of class Aδ and especially C via free nerve endings .
The surface sensitivity can be disturbed due to damage to the nerves , the conduction pathways in the central nervous system or a lack of sensory integration . Perception can be increased ( hyperesthesia ) or decreased ( hypesthesia ), it can be absent ( anesthesia ) or abnormal sensations can occur ( paresthesia ).
With increased tactile perception, one also speaks of tactile defense . This oversensitivity results in a defensive attitude towards the stimuli received. This can be directed against contact by people, but also against materials (sand, mud, dust, paste, felt) or surfaces (metal, wood).
- Martin Grunwald (Ed.): Human Haptic Perception. Basics and Applications. Birkhäuser, Basel a. a. 2008, ISBN 978-3-7643-7611-6 (English).
- Graphic sense of touch - drawing with all human mechanoreceptors
- Touch in the Scholarpedia (English)
- ↑ a b M. Gerstorfer: Crash Course Physiology. Urban & FischerVerlag, 2004, ISBN 3-437-43480-2 , p. 212, (online) .