The document discusses pain and its pathways in the human body. It defines pain and describes its characteristics and theories. It discusses the neurochemistry and types of pain receptors. The main pain pathway described is the lateral spinothalamic tract, which carries pain and temperature sensations from the periphery to the thalamus and somatosensory cortex via the dorsal horn and spinal cord. It relays information via three orders of neurons and can be modulated in the substantia gelatinosa of the spinal cord.
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 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 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 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, Characteristic of pain, Basic consideration of nervous system, Pain receptor, Mechanism of pain causation, Theories of pain, Pathways of pain, Pain Receptors
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, Characteristic of pain, Basic consideration of nervous system, Pain receptor, Mechanism of pain causation, Theories of pain, Pathways of pain, Pain Receptors
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
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
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.
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
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
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
2. Pain and its pathways
Abhishek Roy
II Year PG
OMFS
3. Contents
• Introduction
• Definition
• Incidence of pain
• Characteristics of pain
• Theories of pain
• Neurochemistry of pain
• Types of pain
• Pain receptors
• Pain pathway
• Inhibition of pain
• Conclusion
• References
4. Introduction
• Pain is a sensory experience of special
significance to physicians and basic
scientists.
• It is one of the most common symptoms
which physicians are called to treat.
• The study of physiology of pain has taught
us about various pathways of neural
function.
5. Definition of Pain
• The International Association for the Study of
Pain defined it as an unpleasant sensory and
emotional experience associated with actual
or potential tissue damage, or described in
terms of such damage.
6. Incidence of pain
• A study was conducted by Sukhvinder et al
which concluded that toothache (57.6 %) was
the most commonly reported symptom and
burning mouth sensation (6.4 %) was the least
commonly reported. Majority of the patients had
grade 3 level of pain-related disability (34.8 %)
followed by grade 2 (26.8 %), grade 1 (22.4 %)
and grade 4 levels (16 %).
Prevalence of Various Orofacial Pain Symptoms and Their Overall Impact on Quality of Life in a
Tertiary Care Hospital in India
Sukhvinder Singh Oberoi, S. S. Hiremath, R. Yashoda, Charumohan Marya, Amit Rekhi
J Maxillofac Oral Surg. 2014 Dec; 13(4): 533–538. Published online 2013 Sep 14. doi:
10.1007/s12663-013-0576-6
7. Characteristics of Pain
• Threshold and Intensity :
• If the intensity of the stimulus is below the threshold
level (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.
8. Characteristics of Pain (contd.)
• Adaptation – Pain receptors show no adaptation
and so the pain continues as long as receptors
continue to be stimulated.
• Localization of pain - Superficial pain is
comparatively better localized than deep pain.
• Influence of the rate of damage on intensity of
pain. If the rate of tissue injury (extent of damage
per unit time) is high, intensity of pain is also
high.
9. Factors influencing pain perception
• Emotional status
• Fatigue
• Age
• Fear and apprehension
• Previous experience of pain
11. Intensity theory
• Stated by Goldscheider
based on experiments by
Naunyn in 1859
• Pain is produced when any
sensory nerve is stimulated
by a non-specific sensation
and depends on the
application of high intensity
stimulation
• Disproved for examples like
trigeminal neuralgia where
a gentle touch in a pressure
zone provides excruciating
pain.
12. Specificity Theory
• Postulated by Johannes Muller
in 1842
• Pain is a specific modality
equivalent to vision and
hearing
• It is mediated by free nerve
endings just as Meissner
corpuscles for touch and
Ruffini end organs for warmth
• No longer tenable as free
nerve endings are almost
absent from hairy skin and
cannot be specific receptors to
warmth and cold
13. Pattern Theory
• Goldscheider,1894
• Pain sensation depends
upon spatio-temporal
pattern of nerve impulses
reaching brain
• Warmth, cold and pain
describe reproducable
codes of neural activity
evoked from skin by
changes in environment
14. Gate Control Theory
• Proposed by Melzack and Wall in 1965
• This theory of pain takes into account the relative
input 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
15. Gate Control Theory (contd.)
• 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
18. Neurochemistry of Pain
Damage to tissue cells produces
leakage of intracellular contents
including potassium and histamine,
both of which either activate or
sensitize the nociceptor
• Other compounds such as
acetylcholine, serotonin, and ATP
maybe released by tissue damage and
are known to either activate or
sensitize nociceptors
• Another group of compounds that
synthesize the regions of tissue
damage are the metabolic products of
arachidonic acid. These compounds
are considered inflammatory
mediators and include both
prostaglandins and leukotrienes
• Bradykinin is one of the most potent
pain producing substances that
appears in injured tissue. Bradykinin is
a powerful vasodilator and causes
increased capillary permeability
21. Pain Receptors
• Sensory Receptors -
• Sensory input from various external stimuli is thought to be
received by specific peripheral receptors that act as
transducers and transmit by nerve action potentials along
specific nerve pathways toward the central nervous system.
• Termed first–order afferents, these peripheral terminals of
afferent nerve fibers differ in the form of energy to which they
respond at their respective lowest stimulus intensity, that is,
are differentially sensitive.
• The impulse interpreted is nociceptive (causing pain) if it
exceeds the pain threshold, that is, the intensity of the stimulus
is so great that the receptor is no longer differentially sensitive.
22.
23. Nociceptors
• A nerve ending that responds to noxious stimuli that can
actually or potentially produce tissue damage.
• Free nerve endings - The receptors for fast pain are
sensitive to mechanical or thermal stimuli of noxious
strength.
• The receptors for slow pain are sensitive not only to
noxious mechanical and thermal stimuli but also to a wide
variety of chemicals associated with inflammation :
histamine, serotonin, bradykinin, acetylcholine, potassium
ions and hydrogen ions.
28. First Order Neuron
• Each sensory receptor is attached to a first
order primary afferent neuron that carries
the impulses to the CNS
• The axons of these first-order neurons are
found to have varying thickness
• The larger fibers conduct impulses more
rapidly than smaller fibers
29. Second Order Neuron
• The primary afferent neuron carries impulse
into the CNS and synapses with the second-
order neuron
• This second-order neuron is sometimes
called a transmission neuron since it transfers
the impulse on to the higher centers
• The synapse of the primary afferent and the
second-order neuron occurs in the dorsal
horn of the spinal cord
30. Third Order Neuron
• Cell bodies of third order neurons of the
nociception-relaying pathway are housed in -
» the ventral posterior lateral nuclei
» the ventral posterior inferior nuclei
» the intralaminar thalamic nuclei
Third order neuron fibers from the thalamus
relay thermal sensory information to the
somatosensory cortex
33. Spinothalamic tract
• It is a sensory pathway from the skin to
thalamus
• Sensory information is relayed upward from
the ventral posterolateral nucleus in the
thalamus, to the somatosensory cortex of the
postcentral gyrus.
• The pathway decussates at the level of the
spinal cord, rather than in the brainstem like
the dorsal column-medial lemniscus pathway
and lateral corticospinal tract
34. Spinothalamic tract (contd.)
• The spinothalamic tract consists of two
adjacent pathways
– anterior
– lateral
• The anterior spinothalamic tract carries
information about crude touch
• The lateral spinothalamic tract conveys
pain and temperature
36. Lateral Spinothalamic tract
• It is also called the lateral spinothalamic
fasciculus
• It carries pain and temperature sensory
information (protopathic sensation) to the
thalamus
• It is composed primarily of fast-conducting,
sparsely myelinated A delta fibers and
slow-conducting, unmyelinated C fibers
37. Lateral Spinothalamic tract
• From the site of pain
generation(from the periphery)
the pain senses are carried by
Aδ & C fibres
• Their cell bodies are situated
in the dorsal root ganglion.
• The central processes of the
neuron, lying in the ‘sensory
root’ of the spinal nerve enter
the dorsal horn to terminate in
the SGR ( Substantia
gelatinosa Rolandi), situated in
the tip of dorsal horn
38. Lateral Spinothalamic tract
• From the SGR, 2nd order
neuron arises,
decussates and then
moves up through the
white matter of spinal
cord to reach the brain
• These secondary
neurons are situated in
the posterior horn,
specifically in the Rexed
laminae regions I,II, IV, V
and VI
39. Lateral Spinothalamic tract
• The Rexed laminae comprise
a system of ten layers of grey
matter (I-X), identified in the
early 1950s by Bror Rexed to
label portions of the grey
columns of the spinal cord
• Specific importance in pain
pathway are -
– Region II - Substantia
Gelatinosa of Rolando which
carries out modulation of pain
– Region VI - Base of dorsal
horn through which “fast pain”
travels and flexion reflex is
controlled
40. Lateral Spinothalamic tract
• These fibers will ascend through
the brainstem, including the
medulla oblongata, pons and
midbrain, as the spinal
lemniscus until synapsing in the
ventroposteriorlateral (VPL)
nucleus of the thalamus
• The third order neurons in the
thalamus will then project
through the internal capsule and
corona radiata to various
regions of the cortex, primarily
the main somatosensory cortex,
Brodmann areas 3, 1, and 2.
41. Lateral Spinothalamic tract
• At SGR, there is a synapse between 1st
order & 2nd order neuron. Also there is
synapse of 2nd & 3rd order neuron at
thalamus
• The neurotransmitter at the synapse
between Aδ fiber & 2nd order neuron at
SGR is glutamate while the NT between C
fiber & 2nd order neuron (slow pain) at
SGR is substance P
42. Primary somatosensory cortex
• The primary somatosensory
cortex is located in the
postcentral gyrus, and is part
of the somatosensory system
• Conventionally, areas 3,1,2
have been regarded as the
primary somatosensory cortex
• Recent studies by Kaas has
shown that only area 3 should
be referred to as "primary
somatosensory cortex", as it
receives the bulk of the
thalamocortical projections
from the sensory input fields
44. Neospinothalamic Tract for Fast Pain
• The fast type A(δ) pain fibers transmit
mainly mechanical and acute thermal pain
• They terminate mainly in lamina I at the
dorsal horn and these excite second order
neurons of the neospinothalamic tract
45. Paleospinothalamic tract for Slow
Pain
• This pathway transmits pain mainly from
peripheral slow chronic Type C pain fibers
• In this pathway, the peripheral fibers
terminate almost entirely in lamina II and III
of dorsal horns of spinal cord, together
called as substantia gelatinosa
46.
47. Inhibition of pain
• Pain sensations may be controlled by interrupting
the pain impulse between receptor and
interpretation centers of brain
• This may be done chemically, surgically or by
other means
• Most pain sensations respond to pain reducing
drugs/analgesics which in general act to inhibit
nerve impulse conduction at synapses
• Occasionally however, pain may be controlled
only by surgery.
50. Surgical Approaches
• Sympathectomy – excision of portion of
neural tissue from autonomic nervous
system
• Cordotomy – severing of spinal cord tract,
usually the lateral spinothalamic
• Rhizotomy – cutting of sensory nerve roots
• Prefrontal lobotomy – destruction of tracts
that connect the thalamus with prefrontal
and frontal lobes of cerebral cortex
51. Transcutaneous Electrical
Nerve Stimulation (TENS)
• With TENS, cutaneous bipolar surface electrodes are
placed in the painful body regions and low voltage
electric currents are passed
• Best results have been obtained when intense stimulation
is maintained for at least an hour daily for more than 3
weeks
• TNS portable units are in wider spread use in pain clinics
throughout the world and has been proved most effective
against neuropathic pain
52. Transcutaneous Electrical
Nerve Stimulation (TENS)
• TENS is a method of electrical stimulation
which primarily aims to provide a degree of
symptomatic pain relief by exciting sensory
nerves and thereby stimulating either the
pain gate mechanism and/or the opioid
system
53. Conclusion
• Pain is a multidimensional experience involving
both the sensation evolved by noxious stimuli but
also the relation to it
• The sensation of pain therefore depends in part
on the patient past experience, personality and
level of anxiety
• The most important part of managing pain is
understanding the problem and cause of pain.
• It is only through proper diagnosis that
appropriate therapy can be selected
54. References
• Bell`s ‘Orofacial pain’, 5th edition, Jeffrey P. Okeson
• Text book of Medical Physiology, 2nd edition, Chaudhari
• Text book of Medical Physiology, 10th edition, Arther C
Gyton
• Text book of ‘Oral medicine’- 10th edition, Burkett’s
• Gray's Anatomy – 38th Edition, Churchill Eivingstone
• Online sources