Somatosensory system
Sensory system for touch, pain, temperature, and body position.
Wikipedia / Wikimedia Commons
The somatosensory system, or somatic sensory system, is a subset of the sensory nervous system responsible for the perception of external and internal stimuli, as well as the regulation of body position and balance (proprioception). It acts as a pathway between different sensory modalities within the body and is spread through all major parts of the vertebrate body, consisting of sensory receptors and neurons in the periphery and deeper neurons within the central nervous system.
- field
- Sensory nervous system
- known_for
- Perception of touch, pain, temperature, and proprioception; mapping of body surface in the somatosensory cortex
- subdivisions
- Mechanosensory (touch) and nociception (pain and temperature)
- key_receptors
- Merkel cell nerve endings, tactile corpuscles, Pacinian corpuscles, bulbous corpuscles, nociceptors, thermoreceptors
Lore & Background
The somatosensory system has been thought of as having two subdivisions: one for mechanosensory information related to touch (including light touch, vibration, pressure, and tension in the skin) and one for nociception detection of pain and temperature. The sense of touch uses cutaneous receptors such as mechanoreceptors, nociceptors, and thermoreceptors. Stimulation of these receptors activates peripheral sensory neurons that convey signals to the spinal cord, potentially driving a reflex, and may also be conveyed to the brain for conscious perception. Somatosensory information from the face and head enters the brain via cranial nerves such as the trigeminal nerve.
Reader's Guide
The somatosensory system is significant for its role in enabling organisms to perceive and respond to their environment through touch, pain, temperature, and proprioception. Its neural pathways preserve the location of physical stimuli, creating a sensory map or homunculus in the somatosensory cortex. The system includes specialized receptors like Merkel cell nerve endings for fine touch and Pacinian corpuscles for vibration, and it supports communication through tactile signing and emotional touch. As of 2024, debate continued on the underlying mechanisms, correctness, and validity of the somatosensory system model, and whether it impacts emotions in the body. The system's structure involves a general somatosensory pathway with first-order, second-order, and third-order neurons, and it integrates with other sensory systems for balance and spatial awareness.
Did You Know?
- Humans can communicate specific emotions through touch alone, including anger, fear, disgust, love, gratitude, and sympathy, at much-better-than-chance levels.
- Pacinian corpuscles react to vibrations around 250 Hz and can detect touch sensations on handheld tools.
- Tactile corpuscles are responsible for the ability to read Braille and feel gentle stimuli.
- The insular cortex plays a role in the sense of bodily-ownership, bodily self-awareness, and conveying information about sensual touch, pain, temperature, itch, and local oxygen status.
More in Sensory Systems 1-24
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