Somatosensory system
The
somatosensory system is a complex sensory system. It is made up of a number of different receptors, including thermoreceptors, photoreceptors, mechanoreceptors and chemoreceptors. It also comprises essential processing centres, or sensory modalities, such as proprioception, mechanoreception, thermoception, and nociception. The sensory receptors cover the skin and epithelia, skeletal muscles, bones and joints, internal organs, and the cardiovascular system. While
touch is considered one of the five traditional senses, the impression of touch is formed from several modalities including pressure, skin stretch, vibration and temperature. In medicine, the colloquial term "touch" is usually replaced with "
somatic senses" to better reflect the variety of mechanisms involved. Somatic senses are sometimes referred to as
somesthetic senses, with the understanding that somesthesis includes touch, proprioception and also haptic perception.