Mechanoreceptors can detect pressure at inside or outside body surfaces {touch, sense}. Compression, tension, and torsion stresses cause body-surface strains. Touch analyzes material properties, such as temperature, texture, surface curvature, density, hardness, and elasticity. Touch is a synthetic sense, with some analysis. Protozoa have touch and stretch receptors.
physical properties
Touch events include tissue stresses, motions, and vibrations, which displace surfaces and regions. Stresses vary in area, pressure, and vibration states. Pressures include compression, tension, and torsion. Stresses and stress changes stress skin mechanical receptors.
types
People can feel "butterflies", tickle, tingle, gentle touch, regular pressure, and sharp pressure. People can feel motion and vibrations up to 20 Hz. People can feel object temperature, texture, surface curvature, density, hardness, and elasticity.
Touches relate in only one consistent and complete way. Touches are not symmetric, so touches have unique relations. Touches cannot substitute. Touches have specific sense qualities and so can never switch to other touches. Touches do not have opposites. Touch has same physical properties, and touch processes are similar, so touch perceptions are similar, for all undamaged people.
Touch is pleasurable for babies and parents and for sexual relations. Perhaps, the first touch was for food or mating.
properties
Touch habituates quickly. Touch is in real time, with a half-second delay. Touch can detect low pressure or speed. Touch is painful at high pressure or speed. Touches do not mix to make new touches. Age reduces vibration sensitivity.
source location
Touch can locate body and objects {where system}.
From one location, touch detects only one source.
Touch can detect multiple sensations simultaneously.
Touch has no fixed coordinate origin (egocenter), so coordinates change with task.
evolution
Humans have higher touch sensitivity than other mammals. Lower animals have even less touch sensitivity. Perhaps, the first touch was for food or mating.
Protozoa have touch and stretch receptors.
development
Newborns can turn in touched-cheek direction.
effects
Pressure and touch receptor activity increases muscle flexor activity and decreases muscle extensor activity.
Emotions generate brain-gut hormones that cause abdominal feelings.
relations to other senses
Hearing, temperature, and touch involve mechanical energy.
Touch can feel vibrations below 20 Hz. Sound vibrates eardrum and other body surfaces but is not felt as touch. Touch uses higher energy level than hearing. Hearing uses waves that travel far, but touch uses vibrations that travel short. Hearing and touch have no input from most spatial locations. Hearing has sound attack and decay, and touch has temporal properties.
Touch can feel air near smell receptors and react to noxious smells. Touch locates smell receptors in upper nose.
Touch can feel solutions on tongue and react to noxious tastes. Touch locates tongue taste receptors.
Touch coordinates with vision.
Nociceptive and thermal receptor systems interact. Tactile and thermal receptor systems interact.
Consciousness>Consciousness>Sense>Touch
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Date Modified: 2022.0224