The pain system has skin receptors with ion channels, neurons, fibers, fiber tracts, and brain regions. Pain chemical receptors send to dorsal-horn neurons, which send to cortical regions. Cortex and thalamus control pain {pain, anatomy}.
Skin and body receptors (nociceptor) chemically bind endomorphins, prostaglandins, bradykinin peptides, and protein hormones (such as nerve growth factor), molecules released by inflammation and tissue damage [Woolf and Salter, 2000].
fibers
Body organs and mesentery have pain fibers. Internuncial neurons have pain fibers. Pain fibers are A, C, III, IV, and nociceptive fibers. Large myelinated fibers detect moderate stimulation. Small myelinated fibers detect all stimulations. Myelinated fibers detect sharp localized skin pain. Unmyelinated fibers detect dull deep unlocalized body pain. Itching nerves are separate from pain nerves.
brain
Anterior cingulate gyrus, frontal lobe, Lissauer's tract, locus coeruleus, nociceptive system, protopathic pathway, raphé nuclei, reticular formation, sensory reticular formation, sensory thalamus, spinal cord, spinoreticular tract, and spinothalamic tract affect pain. Throbbing pain, burning pain, and sharp pain use different brain regions. Cingulate cortex receives pain information [Chapman and Nakamura, 1999]. Cortex has pain center connected to sense areas. Reticular formation regulates pain.
brain pathways
Feeling pain and reacting to it involve separate pathways. Spinothalamic tract and central gray-matter path carry pain fibers. Internuncial neurons have pain fibers. Body organs and mesentery have pain fibers. Lemniscal tract has no pain fibers but affects pain. Abdominal pain signals travel in subdiaphragmatic vagus nerve to nucleus tractus solitarius, nucleus raphe magnus, and spinal-cord dorsolateral funiculus [Ritter et al., 1992].
Consciousness>Consciousness>Sense>Pain>Anatomy
1-Consciousness-Sense-Pain-Anatomy
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Date Modified: 2022.0224