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Pain pathways
The document presents a comprehensive overview of pain, including its definitions, history, and the complex neural pathways involved in pain sensation. It explains the mechanisms of nociceptors and the classification of pain pathways, as well as various theories of pain like specificity, pattern, and gate control theories. Additionally, it cites multiple educational resources and emphasizes the emotional and sensory experience of pain associated with potential tissue damage.
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Pain pathways
- 1. Presenter – DrSiddharth
- 2. • Introduction • History •Definitions • Receptors of pain • Neurotransmitters in pain sensation • Theories of pain • Neural pathway of pain • Tracts of spinal cord • Pathways of pain sensation • Conclusion • References
- 3. • Pain isdefined as an “unpleasant emotional experience usually initiated by a noxious stimulus and transmitted over a specialized neural network to the central nervous system where it is interpreted as such”. Monhiem’s • an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage“ • International Association For The Study Of Pain
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- 7. FIELDS has described that thesubjective experience of pain arises by 4 distinct process Transduction Transmission Modulation Perception
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- 12. • Free nerveendings – responsible for carrying noxious stimulus from both superficial as well as deep somatic and visceral pain sensations therefore reffered as nociceptors
- 15. SENSORY NEURONS First OrderSecond Order Third Order
- 19. • According totype of impulses they carry second order neuron can be classified as – • LOW THRESHOLD MECHANOSENSORY( ligth touch, pressure and Proprioception) • NOCIOCEPTIVE SPECIFIC ( Noxious stimulation) • WIDE DYNAMIC RANGE ( wide range of stimulus intensities from nonnoxious to noxious. • SILENT NOCICEPTORS (It is an afferent neuron that appear to remain or silent to any mechanical stimulation .These neuron become active with tissue injury and add to the nociceptive input entering the CNS.
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- 33. • Central pain •Projected pain • Referred pain
- 36. • 3 rulesof referred pain • Follows the trigeminal lamination pattern • Rarely crosses midline • If pain felt outside the nerve that mediates pain it is generally felt cephalic to nerve that is upward towards head not caudally.
- 39. • THEORIES OFPAIN • Specificity Theory • Pattern Theory • Gate Control Theory
- 40. • SPECIFICITY THEORY •DESCARTES 1664, MULLER 1840 • Pain occurs due to stimulation of specific pain receptors (nociceptors) with transmission by nerves directly to the brain • PATTERN THEORY GOLDSCHEIDER – 1894-- stimulus intensity and central summation are critical determinants of pain • Particular patterns of nerve impulses that evoke pain are produced by summation of sensory input within the dorsal horn of spinal cord
- 41. • Ronald Melzackand Patrick D. Wall-1965
- 44. • Endogenous morphine •Enkephalin and endorphins • Forms the basis of acupuncture and use of opiods
- 46. • Textbook OfMedical Physiology -Guyton & Hall 11thedition • Essentials Of Medical Physiology -K. Sembulingam 5th Edition • Textbook Of Local Anaesthesia-monheims • Orofacial Pain- Okeson • Textbook Of Physiology- A .K. Jain • Sicher & Dubrauls Oral Anatomy
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Editor's Notes
- #21 With in the dorsal horn there r interneurons which have excitatory or inhibitory effect on impulses transferred by the primary neurons that meeans when some of these interneurons r stimulated they have excitatory affect on impulse where as other have inhibitory effects n and there is significant population of these interneuron in lamina 2 n 3 collectively knwn as substantia gelatinosa
- #32 Deep afferents converges more than superficial thts y deep pain difficult to localise