Physiology of Pain, Characteristic of pain, Basic consideration of nervous system, Pain receptor, Mechanism of pain causation, Theories of pain, Pathways of pain, Pain Receptors
Pain is one of the most commonly experienced symptom . It is often spoken of as a protective mechanism since it is usually manifested when an environmental change occurs that causes injury to responsive tissue
Pain is one of the most commonly experienced symptom . It is often spoken of as a protective mechanism since it is usually manifested when an environmental change occurs that causes injury to responsive tissue
Pain is defined 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”.
Free nerve endings – responsible for carrying noxious stimulus from both superficial as well as deep somatic and visceral pain sensations therefore reffered as nociceptors
According to type 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.
Pain is one of the most commonly experienced symptom . It is often spoken of as a protective mechanism since it is usually manifested when an environmental change occurs that causes injury to responsive tissue
Pain is one of the most commonly experienced symptom . It is often spoken of as a protective mechanism since it is usually manifested when an environmental change occurs that causes injury to responsive tissue
Pain is defined 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”.
Free nerve endings – responsible for carrying noxious stimulus from both superficial as well as deep somatic and visceral pain sensations therefore reffered as nociceptors
According to type 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.
Physiology of Pain (PPT) Nervous System PhysiologyShaista Jabeen
https://www.youtube.com/channel/UCrrAABI7QDRCJ1yMrQCip_w/videos
https://www.facebook.com/ShaistaJabeeen/
https://www.facebook.com/Human-Physiology-Lectures-100702741804409/
Physiology of Pain (PPT)
Nervous System Physiology
INTRODUCTION
BENEFITS OF PAIN SENSATION
COMPONENTS OF PAIN SENSATION
PATHWAYS OF PAIN SENSATION
FROM SKIN AND DEEPER STRUCTURES
FROM FACE
FROM VISCERA
FROM PELVIC REGION
VISCERAL PAIN
CAUSES OF VISCERAL PAIN
REFERRED PAIN
DEFINITION
EXAMPLES OF REFERRED PAIN
MECHANISM OF REFERRED PAIN
NEUROTRANSMITTERS INVOLVED IN PAIN SENSATION
ANALGESIA SYSTEM
ANALGESIC PATHWAY
GATE CONTROL THEORY
APPLIED PHYSIOLOGY
Short Notes
pdf ppt
Pain pathway gate control theory
Pain management
An unpleasant emotional experience usually initiated by noxious stimulus and transmitted over a specialized neural network to CNS where it is interpreted as such.
1. Exteroceptors: arising from receptors from skin & mucosa. sensed at conscious level
E.g. Merkel corpuscles : Tactile receptors.
Free Nerve ending :Perceive superficial pain.
2. Proprioceptors : From musculoskeletal structures.
The presence , positions & movement of body. below conscious levels.
E.g. 1) Muscle spindles : Skeletal muscle fibers. Mechanoreceptors.
2) Free nerve ending : Perceive deep somatic pain & other sensations.
3. Interoceptors : From viscera of body below conscious level.
E.g. Pacinian corpuscles : perception of touch-pressure.
Free nerve ending : Perceive visceral pain & other sensations.
Pain is the common symptom in many chronic conditions such as cancers, neuropathies, and chronic disease. It is also experienced in trauma varying from mild to severe based on the location and degree of trauma. This presentation is a brief outline on types of pain, classification of pain, pain pathways and management of pain
Physiology of Pain (PPT) Nervous System PhysiologyShaista Jabeen
https://www.youtube.com/channel/UCrrAABI7QDRCJ1yMrQCip_w/videos
https://www.facebook.com/ShaistaJabeeen/
https://www.facebook.com/Human-Physiology-Lectures-100702741804409/
Physiology of Pain (PPT)
Nervous System Physiology
INTRODUCTION
BENEFITS OF PAIN SENSATION
COMPONENTS OF PAIN SENSATION
PATHWAYS OF PAIN SENSATION
FROM SKIN AND DEEPER STRUCTURES
FROM FACE
FROM VISCERA
FROM PELVIC REGION
VISCERAL PAIN
CAUSES OF VISCERAL PAIN
REFERRED PAIN
DEFINITION
EXAMPLES OF REFERRED PAIN
MECHANISM OF REFERRED PAIN
NEUROTRANSMITTERS INVOLVED IN PAIN SENSATION
ANALGESIA SYSTEM
ANALGESIC PATHWAY
GATE CONTROL THEORY
APPLIED PHYSIOLOGY
Short Notes
pdf ppt
Pain pathway gate control theory
Pain management
An unpleasant emotional experience usually initiated by noxious stimulus and transmitted over a specialized neural network to CNS where it is interpreted as such.
1. Exteroceptors: arising from receptors from skin & mucosa. sensed at conscious level
E.g. Merkel corpuscles : Tactile receptors.
Free Nerve ending :Perceive superficial pain.
2. Proprioceptors : From musculoskeletal structures.
The presence , positions & movement of body. below conscious levels.
E.g. 1) Muscle spindles : Skeletal muscle fibers. Mechanoreceptors.
2) Free nerve ending : Perceive deep somatic pain & other sensations.
3. Interoceptors : From viscera of body below conscious level.
E.g. Pacinian corpuscles : perception of touch-pressure.
Free nerve ending : Perceive visceral pain & other sensations.
Pain is the common symptom in many chronic conditions such as cancers, neuropathies, and chronic disease. It is also experienced in trauma varying from mild to severe based on the location and degree of trauma. This presentation is a brief outline on types of pain, classification of pain, pain pathways and management of pain
Pain 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
Definition n classification •Pathophysiologyof pain. •Physiological Effects of pain. •Pharmacological & non-pharmacological methods of analgesia. •Principles of pain management.METHODS OF CONTROLLING METHODS OF CONTROLLING
Non-pharmacological Preoperative counseling TENS Acupuncture
Pharmacological Opioids •Im •IV infusion •IV PCA Local anaesthetics: •Local Infiltration •Nerve Blocks •Epidural Blocks NSAIDS •IM •IV infusion •IV PCA
NON-PHARMACOLOGICAL METHODS PRE-OP COUNSELLING: Well informed patients about: •Nature of operation •Nature of post operative pain •Methods of analgesia available
Cope better with Post –op Pain
NON-PHARMACOLOGICAL METHODS TENS (Trans Cutaneous electric nerve stimulation)
Stimulates afferent myelinated (A-beta) nerve fibers at 70hz
Inhibitory circuits within sp cord activated
Nerve impulse transmission reduced
Maximum benefit in neurogenic pain
PHARMACOLOGICAL METHODS OPIODS •Activate opiodreceptors within the CNS •Reduce transmission of nerve impulses by modulation in the dorsal horn
PHARMACOLOGICAL METHODS
LOCAL ANAESTHETICS –Blocks the conduction of nerve impulses –Can be given with adrenaline because •Decreases absorption of L.A allowing larger doses •Also acts on alpha 2 receptors which potentiates analgesic effect
PHARMACOLOGICAL METHODS
NASIDS –Blocks synthesis of PG’s –Only suitable for miledto moderate pain
PRINCIPLE OF MANAGEMENT OF PAIN •Pre-emptive analgesia •Balanced or combination analgesia •Analgesia ladder
PHARMACOLOGICAL METHODS
Balanced Analgesia –NASID are used in conjunction with opioids. –Reduces amount of opioids –Reduces side affect of opioids,ASSESMENT OF PAIN •Observe the behaviour of the patient •Monitor analgesic requirement of the patient –Visual Analogue Score( VAS )
–Verbal Rating Score ( VRS ) •None •Mild •Moderate •severe
Behavioral sciences and its application to pedodontics
Behavior modification
Behavior Shaping
Communication and communicative guidance
Tell-show-do
Voice control
Nonverbal communication
Positive reinforcement
Distraction
Nitrous oxide/oxygen inhalation
Protective stabilization
Sedation
General anaesthesia
General anesthesia
HISTORY OF ANESTHESIA, ADVANTAGES AND DISADVANTAGES OF GENERAL ANESTHESIA, INDICATIONS AND CONTRAINDICATIONS OF GENERAL ANESTHESIA, PREOPERATIVE EVALUATION, PREANAESTHETIC MEDICATION, STAGES OF GENERAL ANESTHESIA, VITAL SIGNS, CLASSIFICATION OF GENERAL ANESTHESIA, ASA CLASSIFICATION, Isoflurane, Sevoflurane, Desflurane, Fentanyl , KETAMINE
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
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Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
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These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
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1. PHYSIOLOGY OF PAIN
DR. DHARATI PATEL
DEPARTMENT OF PEDODONTICS AND PREVENTIVE
DENTISTRY
Perhaps the capacity of the human brain falls short of the
ability to understand its own complexity
-Thibodeau
2. Content
Introduction
Definition
Historical aspect
Characteristic of pain
Basic consideration of nervous system
Pain receptor
Mechanism of pain causation
Theories of pain
Pathways of pain
References
3.
4. Introduction
Pain is an unpleasant sensory action
Seriously impairs the lives of millions of people around the world
Described in many ways by patient
5. Pain is
Subjective
Protective
and it is modified by developmental, behavioural, personality
and cultural factors
It is a symptom
Associated signs are crying, sweating, increased heart
rate, blood pressure, behavioral changes etc.
6. Produced by real or potential injury to the body
localized to the area stimulated but the experience involves the
whole being.
Pain also imply that the same painful experience may evoke
widely different degrees of suffering in different persons, and
even in the same person under different circumstances.
It is expressed in terms of damage done by the injury
7. In 1984, Bonica reported that nearly 1/3rd of the population in
industrialized nations suffer to some extent from chronic pain.
This results in loss of billions annually in health care services, loss
of work, decreased productivity and disability compensation
The clinical management of pain is the primary concern of health
professionals around the world.
8. Benefits of pain
Pain is a protective mechanism for the body, it occurs whenever any
tissues are being damaged, and it causes the individual to react to
remove the pain stimulus
Gives warning signal – creates awareness of injury
Prevents further damage – causing reflex withdrawal of the body
Forces the person to rest or to minimize the activities thus enabling
the rapid healing of injurious part
9. Definition
• Poin/Poena – punishment
Pain
• “An unpleasant sensory or emotional experience associated with
actual or potential tissue damage, described in terms of such
damage“
International Association for the Study of Pain
(1979)
American Pain Society[APS]2003
• Pain is whatever the experiencing person says it is, existing
whenever he/she says it does
Margo Mc Caffey (1999)
10. Cancer Web
(2011)
• An unpleasant sensation induced by noxious
stimuli and generally received by specialized
nerve endings.
Bell
• The subject’s conscious perception of
modulated nociceptive impulses that generate
an unpleasant sensory and emotional
experiences associated with actual or potential
tissue damage or described in terms of such
damage.
Monheim’s
• An unpleasant emotional experience usually
initiated by noxious stimulus and transmitted
over a specialized neural network to CNS
where it is interpreted as such damage.
12. Inducing pain
ALGOGENIC
Pain that occurs without noxious stimulation at the site of pain
ALLODYNIA
absence to pain perception
ANALGESIA
Absence of all sensation
ANESTHESIA
Unpleasant sensation with or without stimulus
DYSESTHESIA
Diminished response to noxious stimulus
HYPOALGESIA
Increased pain from a stimulus that normally provokes pain
HYPERALGESIA
Reduced cutaneous sensation
HYPOASTHESIA
Increased response to mild stimulus
HYPERASTHESIA
An abnormal sensation perceived without an apparent stimulus
PARASTHESIA
13. Pain in disturbance of a nerve
NEURALGIA
The mechanism that provides for the reception and conversion of noxious
and or potentially noxious stimuli into neural impulses and the
transmission of such impulses by A-delta and C-fibers to the CNS where
they are modulated and acted on.
NOCICEPTION
an afferent neural pathway that mediates pain
NOCICEPTIVE
PATHWAY
a sensory receptor preferentially sensitive to noxious or
potentially noxious stimuli.
NOCICEPTOR
Increased responsiveness of nociceptive neurons to their normal
input
SENSITIZATION
pain that is felt in a tooth
ODONTALGIA
14. Historical aspect
Homer pain was due to arrows shot by the gods
Aristotle a “passion of the soul” that somehow resulted from
intensification of other sensory experience
Plato pain and pleasure arose from within the body i.e. pain is an
emotional experience more than a localized body disturbance
Bible anguish of the soul
Freud symptoms such as pain could develop as a solution to
emotional conflicts
15. 1664 AD - Descartes introduced the concept of pain
pathway.
Recent years – Specialization of nociceptive pathways
have been identified.
16. Incidence of pain
According to Cohen – It was found that 21.8% of adult in the
United States experience orofacial pain symptoms within 6
months of study.
The most common pain was toothache, which was estimated
to have occurred in 12.3% of the population
18. Threshold and Intensity
If the intensity of the stimulus is below the threshold (sub-
threshold) pain is not felt. As the intensity increases more and
more, pain is felt more and more according to the Weber-
Fechner’s law.
This law ensures that while our body can perceive pain due to
low intensity stimulus, a severe crushing injury will not cause
death due to pain sensation, yet as stimulus increases, sense of
perception also increases.
19. Adaptation
Pain receptors show no adaptation and so the pain continues as
long as receptors continue to be stimulated.
Localization of pain
Pain sensation is somewhat poorly localized. However superficial
pain is comparatively better localized than deep pain.
Rate of damage
damage = intensity of pain
If the rate of tissue injury (extent of damage per unit time) is
high, intensity of pain is also high.
21. The human being is a phenomenal organism with the
complexity far beyond the imagination of the best
scientific minds
Because of its complexity, a master control system, the
“Nervous system” …coordinate all the activities.
In order to manage the patients pain problem
understanding the normal function of the nervous system is
necessary
26. Neuron
It is a structural and functional unit of nervous system
Called as “ nerve cell”
It is different from other cells in the body in 2 ways:
1. It has processes called as axon & dendrites
2. Does not have centrosome- cannot differentiate
27. Classification
1.Depending upon the number of poles
Unipolar
Bipolar
Multipolar
2. Depending on function
Motor
Sensory
3. Depending on length
Golgi type I
Golgi type II
33. 1. Nerve cell body
Known as soma or perikaryon
Irregular in shape
Consists of cytoplasm known as- neuroplasm
Covered by cell membrane
Cytoplasm contains large nucleus, nissl bodies, neurofibrils,
mitochondria and golgi apparatus
2. Dendrite
Branched process of neuron
It contains nissl granules and neurofibrils
Conductive in nature- transmits impulses towards cell body
34. 3. Axon
Arise from nerve cell body
Extends for a long distance away from cell body
35. Internal structure
It has a long central core of cytoplasm – axoplasm
Axoplasm covered by tubular membrane-axolemma
Axoplasm+ axolemma = axis cylinder of nerve fibre
Mylein sheath
Axons insulated by myelin sheath
Does not form a continuous sheath and is absent at intervals- node
of Ranvier
Segment of nerve fibre between the nodes – internode
Responsible for faster nerve conduction where the impulse jumps
from one node to other
Acts as an insulator
36. Neurilemma
Surrounding the myelin sheath there is thin membrane –
neurilemma/ sheath of Schwann
Contains – Schwann cells
The cells have flat & elongated nuclei
37. Classification of nerve-fibers
1. Depending on structure
Myelinated
Nonmyelinated
2. Depending on distribution
Somatic
Visceral
3. Depending on origin
Cranial
Spinal
4. Depending on function
Motor
sensory
38. 5. Depending on secretion of neurotransmitter
Adrenergic
Cholinergic
39. Depending on diameter and conduction
Type A fibers
Alpha fibers: size - 13 to 20 µm, velocity - 70 to 120 m/ s.
Beta fibers: size – 6 to 13 µm, velocity – 40 to 70 m/s.
Gamma fibers: size – 3 to 8 µm, velocity – 15 to 40 m/s.
Delta fibers: size – 1 to 5 µm, velocity – 5 to 15 m/s.
Type B fibres
Size- 1 to 2 µm, 3-10 m/s.
Type C fibers
Size – 0.5 to 1 µm, velocity – 0.5 to 2 m/s.
44. Sensory Receptors :
Input to the nervous system is provided by sensory receptors that
detect such sensory stimuli such as touch, sound, pain, cold and
warmth.
All the stimuli capable of evoking pain are noxious because they are
associated with actual or potential tissue injury.
Sherrington postulated the existence of sensory receptors that sensed
noxious agents and called nociceptors.
Perception of pain
44
nociception
45. Pain Receptors:
Pain Receptors Are Free Nerve Endings.
Widespread in the superficial layers of the skin, periosteum, the
arterial walls, the joint surfaces, and the falx and tentorium in the
cranial vault.
Most other deep tissues are only sparsely supplied with pain
endings.
45
47. Fields has described that the subjective experience of pain arises by
four distinct processes
Transduction
Transmission
Modulation
Perception
48. A pain sensation to reach the cortex from the nosiceptors it requires
three neuron sets.
NOCICEPTORS
BRAIN STEM SPINAL CORD
THALAMUS
CEREBRAL CORTEX
Spinal nerve
Cranial nerve
B
B
C
C
A A
A - 1st order neuron
B - 2nd order
C - 3rd order.
51. All or none phenomenon:
The action potential either happens completely or it doesn’t happen at all.
Coding for stimulus intensity:
Once generated all action potentials are independent of the stimulus
strength, and all action potentials are alike. Strong stimuli cause nerve impulses
to be generated more often in a given interval of time than do weak stimuli.
Thus stimulus intensity is coded for by the number of impulses generated per
sec- i.e. by frequency of impulse transmission.
52. Absolute and Relative refractory period:
When a patch of neuron membrane is generating an action potential and it’s Na
voltage gates are open, the neuron is incapable of responding to another
stimulus no matter how strong it may be Absolute refractory period.
Relative refractory period is the interval following the absolute refractory
period when the Na gates are closed, and the K gates are open, and
repolarization is occurring. During this time the axons threshold for impulse
generation is substantially elevated. A threshold stimulus is unable to trigger an
action potential, but an exceptionally strong stimulus can reopen the Na gates
and allow another impulse to be generated.
53. Synapse Or Synaptic Junction:
It is a unique junction that mediates the transfer of information from one
neuron to the next, or neuron to an effector cell.
Types
1. Electrical
2. Chemical
54. Neuronal Sensitization:
When the excitatory neurotransmitters are released in the synaptic cleft, the
post synaptic neuron is excited and an impulse is started and carried down the
axon. If the excitatory neurochemicals remain in the region of the synapse, the
neuron can be depolarized quicker with the next release of neurotransmitter.
This process is called sensitization. This could be the cause for hyperalgesic
state in inflammatory tissues.
56. It is often assumed that pain is a warning that damage has
occurred. But this is not strictly true.
Because pain may occur when there is no obvious disease as in
primary neuralgias and many diseases does not cause pain, at
least in the early stages.
So these are various theories being put forward on how nerve
impulses give rise to sensation of pain.
56
57. INTENSITY THEORY
According to this view, pain is produced when any sensory nerve
is stimulated beyond a certain level.
In other words pain is supposed to be a non-specific sensation
and depends only on high intensity stimulation.
But the trigeminal system provides an example against this
theory. In case of trigeminal neuralgia the patient can suffer
excruciating pain from a stimulus no greater than a gentle touch
provided it is applied to a trigger zone.
Although, the intensity theory is not accepted, it remains true
to say that intensity of stimulation is a factor in causing pain.
57
58. Specificity Theory (Johannes Muller, 1842)
According to this view, pain is a specific modality equivalent to vision and
hearing etc.
Just as there are Meissner corpuscles for the sensation of touch, Ruffini end
organs supposedly for warmth and Krause end organs supposedly for cold, so
also pain is mediated by free nerve endings.
Certain psychophysical studies have been regarded as supporting specificity
theory. Specialization is known to exist in nervous system and there are well
known tracts.
But concept of specific nerve ending is no long tenable. The Krause and
Ruffini endings are absent from the dermis of about all hairy skin, so it is
certain that these structures cannot be receptors for cold and warmth.
58
59. Protopathic and Epicritic theory:
Head and Rivers (1908) postulated the existence of two
cutaneous sensory nerves extending from the periphery to the
CNS.
The protopathic system is primitive, yielding diffuse impression
of pain, including extremes of temperature and is upgraded.
The epicritic system is concerned with tough discrimination and
small changes in temperature and is phylogenetically a more
recent acquisition.
59
60. Pattern theory (Goldscheider, 1894):
This theory states that pain sensation depends upon
spatio – temporal pattern of nerve impulses reaching
the brain.
According to Woddell (1962) warmth, cold and pain
are words used to describe reproducible spatio –
temporal pattern, or codes of neural activity evoked
from skin by changes in environment.
The precise pattern of nerve impulse entering the
CNS will be different for different regions and will
vary from person to person because of normal
anatomical variations. 60
61. Gate Control Theory
This theory proposed by Melzack and Wall in 1965 and recently
re-evaluated is receiving considerable attention.
This theory of pain takes into account the relative in put of
neural impulses along large and small fibers, the small nerve
fibers reach the dorsal horn of spinal cord and relay impulses
to further cells which transmit them to higher levels.
The large nerve fibers have collateral branches, which carry
impulses to substantia gelatinosa where they stimulate
secondary neurons.
61
62. The substantia gelatinosa cells terminate on the smaller nerve
fibers just as the latter are about to synapse, thus reducing
activity, the result is, ongoing activity is reduced or stopped –gate is
closed.
The theory also proposes that large diameter fiber input has ability
to modulate synaptic transmission of small diameter fibers within
the dorsal horn.
Large diameter fibers transmit signals that are initiated by
pressure, vibration and temperature; small diameter fibers transmit
painful sensations.
Activation of large fiber system inhibits small fiber synaptic
transmission, which closes the gate to central progression of
impulse carried by small fibers.
62
67. Sensory pathways for transmitting
somatic signals into CNS
Somatic segment Spinal cord Brain
1. The dorsal columm-medial lemniscal system or
2. The anterolateral system.
Partially at the level of the thalamus.
68. Dorsal column-medial lemniscal system
Composed of large, myelinated nerve fibers
At velocities of 30-110m/sec.
Has a high degree of spatial orientation.
Rapidly and with temporal and spatial fidelity.
Touch, vibrating, position from the joints, pressure.
69. Anterolateral pathway
Composed of smaller myelinated fibers.
At velocities ranging from a few meter per second up to 40m/sec.
Less spatial orientation.
Does not need transmitted rapidly or with great spatial fidelity.
Ability to transmit the broad spectrum of sensory modalities-
Pain, warmth, cold, and crude tactile sensations.
70. Anatomy:
Originate mainly in: dorsal lamina I, IV, V and VI.
Upper terminals mainly two folds:
Reticular nuclei of the brain stem
The ventrobasal complex and the intralaminar nuclei.
Small fraction : Ventrobasal complex of thalamus.
Most of : Reticular nuclei Intralaminar nuclei Further proceed.
71. Dual pathways for pain
Free nerve endings
Use two separate pathways.
1. Fast pain pathway
2. Slow pain pathway
72. Neospinothelmic tract for fast
pain:
Elicited by either mechanical or thermal pain
stimuli
By small type AꝽ
At velocities between 6 to 30 m/sec.
Terminate mainly in lamina I.
Can be localized much more exactly.
Glutamate is neurotransmitter at the type AꝽ
pain nerve fiber.
73. • A few fibers: reticular areas of brain
stems.
• Most of : Ventrobasal complex.
• Can be localized much more exactly.
• Glutamate is neurotransmitter at
the type AꝽ pain nerve fiber.
74. Paleospinothalmic pathway for
slow pain
Elicited by chemical types of pain stimuli.
Sometimes by thermal or mechanical.
By type C fibers.
Although transmit signals from AꝽ fibers also.
At velocities between 0.5 and 2m/sec.
Terminate in laminae II and III together called substantia
gelatinosa then through short fiber neurons entering to
lamina V.
75. Type C secrete glutamate and substance P.
Glutamate act instantaneously and last for few milliseconds.
Substance P released slowly, building up in concentration over a period
of seconds or even minutes.
Localization is poor.
Localized to major part but not specific point.
synaptic , diffuse connectivity.
76. • Slow pathway terminates mostly into the brainstem only.
• 1/10 to ¼ pass : Thalamus.
• Most of terminate:
1. Reticular nuclei of medulla, pons, mesencephalon
2. Tectal area of mesencephalon deep to the sup. and inf. colliculi.
3. The periaqueductal gray region.
• This region is important.
77. Surgical interruption
Severe and intractable pain: pain nervous pathway can be
cut at any one of several points.
Lower part of body: cordotomy for few week to a few
months.
Cordotomy not always successful.
Second, cauterize specific pain areas.
79. 1. Bell`s ‘Orofacial pain’, 5th edition, Jeffrey P. Okeson.
2. Text book of Medical Physiology, 2nd edition, Chaudhari.
3. Text book of Medical Physiology, 10th edition, Arther C Gyton.
4. Dental Clinics of North America 1978: 22 (1); 1-61.
5. Text book of ‘Oral medicine’- 10th edition, Burkett’s.
6. Gray's Anatomy – 38th Edition, Churchill Eivingstone.
7. Understanding “Medical physiology”- 3rd edition, R L Bijlani.
8. Core Topics in Pain – Anita Holdcroft, Sian Jagger.
79
80. 80
9. Pain – Wikipedia, the free encyclopedia
10. Rolf-Detlef Treede. Neurophysiological studies of pain pathways in
peripheral and central nervous system disorders. J Neurol (2003) 250 : 1152–
1161.
11. Ascending Sensory Pathways, Chapter 10.
12. Pain pathway & Medications – Painexplained.ca, The Canadian Pain Society.