Sensory and Pain pt. 1

I have done some deep research on the physiology of pain and nociception. Upon discovering how sensitive I really am to various stimuli, this made me want to learn more about pain and what causes pain besides injury from noxious stimulus - thermal(extreme temperatures), mechanical(physical damage or force to skin, tissue, and bone), and chemical(caustic or irritating substance damage). I have also learned a better way to describe whatever kind of pain I'm feeling. I can feel both somatic(more acute and well localized) and visceral(achy and poorly localized) pain in my side.

Figuring out better ways to describe and compartmentalize my pain will help me discern better. I have learned about hyperalgesia which is an increased sensitivity to pain. The kind of pain that I feel did not come from an injury and it isn't a visible force. I am certain I was born with this acute sensitivity to earthquakes. It just did not develop until I matured, especially into adulthood and after visiting a tectonic plate boundary for the first time. I don't think earthquake energy or strain energy before manifesting as an earthquake is considered a noxious stimulus, at least not the energy itself. However, the violent shaking in the ground can break a person's ankle if they are standing, walking, or running - That would be a mechanical force.

However, I feel pain from potential earthquakes or earthquakes that have not actually happened yet. I'm learning about somatosensation now. This might involve mechanoreceptors(cells or sense organs that respond to mechanical stimuli such as touch or sound). There are 3 classes of mechanoreceptors: tactile, proprioceptors, and baroreceptors. Mechanoreceptors sense stimuli due to physical deformation of their plasma membranes. They contain mechanically-gated ion channels whose gates open and close in response to pressure, touch, stretching, and sound. There are 4 primary tactile mechanoreceptors in the skin: Merkel's disks, Meissner's corpuscles, Ruffini endings, and Pacinian corpuscle; Two are located toward the surface of the skin and two are located deeper.

A fifth type of mechanoreceptor, Kraus end bulbs, are found only in specialized regions. Merkel's disks are unencapsulated and they respond to light touch. Meissner's corpuscles, Ruffini endings, Pacinian corpuscle, and Kraus end bulbs are all encapsulated. Meissner's corpuscles respond to touch and low frequency vibration. Ruffini endings detect stretch and deformation within joints and warmth. Pacinian corpuscles detect transient pressure and high frequency vibration. Kraus end bulbs detect cold. Meissner corpuscles are found in the upper dermis, but project into the epidermis. They are primarily found in the glabrous(smooth, hairless) skin on the fingertips and eyelids. They respond to fine touch and pressure, but they also respond to low frequency vibration or flutter.

Deeper in the dermis are Ruffini endings. They are found in both glabrous and hairy skin. These are slow-adapting mechanoreceptors that detect skin stretch and deformation within joints. They also contribute to proprioception and kinesthesia. They also detect warmth. Pacinian corpuscles are found deep in the dermis of both glabrous and hairy skin. They are found in bone periosteum, joint capsules, pancreas, and other viscera, breast, and genitals. These are fast-adapting mechanoreceptors that sense deep, transient(not prolonged pressure), and high-frequency vibration. Pacinian corpuscles detect pressure and vibration by being compressed which stimulates their internal dendrites.