SlideShare una empresa de Scribd logo
1 de 20
Descargar para leer sin conexión
Response of neurons & nerve fibers to injury
Types of injury
Wallerian degeneration, regeneration &
Factors for regeneration
RK Goit, Lecturer
Department of Physiology
• Neuron is the basic function unit of the nervous
system.
• In the mature human, if it is destroyed, it is not
replaced.
• It may be injured due to various reasons(cutting,
crushing, pull & pressure).
• These injuries may damage a nerve variously &
the injury is classified according to the extent of
the damage.
Nerve injury
Nerve injury
Seddon (1944) described 3 clinical types of nerve injury:
• Neurapraxia (Class I)
• the term applied to a transient block
• paralysis is incomplete, recovery is rapid & complete,
& there is no nerve degeneration
• pressure is the most common cause
• Axonotmesis (Class II)
• the term applied to a nerve lesion in which the axons
are damaged but the surrounding connective tissue
sheaths remain intact
• Wallerian degeneration occurs peripherally
• functional recovery is more rapid & more complete
than after complete section of the nerve trunk
• crush injuries, traction, & compression are the most
common causes
• Neurotmesis (Class III)
• the term applied to complete section of the
nerve trunk
• occur on severe contusion, stretch, laceration
Sunderland (1951) expanded Seddon’s classification
to 5 degrees:
• First-degree (Class I)
• Seddon’s neurapraxia & first-degree are the same
• Second-degree (Class II)
• Seddon’s axonotmesis & second-degree are the
same
• Third-degree (Class II)
• nerve fiber interruption
• there is a lesion of the endoneurium, but the
epineurium & perineurium remain intact
• recovery from a third-degree injury is possible, but
surgical intervention may be required
• Fourth-degree (Class II)
• only the epineurium remain intact
• surgical repair is required
• Fifth-degree (Class III)
• lesion of complete transection of the nerve
• Recovery is not possible without an appropriate
surgical treatment
Nerve injury
Injury of the Nerve Cell Body
• Severe damage of the nerve cell body may
result in degeneration of the entire neuron
• In the CNS, the tissue macrophages (microglial
cells) remove the debris, & the neighboring
astrocytes replace the neuron with scar tissue
• In the PNS, the tissue macrophages remove the
debris, & the local fibroblasts replace the neuron
with scar tissue
Injury of the Nerve Cell Process
• if the axon of the nerve cell is
divided, degenerative changes will take place
in
1. distal segment of the axon
2. a portion of the axon proximal to the injury
3. the cell body from which the axon arises
Changes in the Distal Segment of the Axon
• wallerian degeneration is the changes that occur
distally to the site of damage on an axon
• axon becomes swollen & irregular; the axon is
broken into fragments, & the debris is digested by
surrounding Schwann cells & tissue macrophages
• entire axon is destroyed within a week
• myelin sheath is converted into lipid droplets
• the droplets are extruded from the Schwann cell
& subsequently are phagocytosed by tissue
macrophages
• Schwann cells now begin to proliferate rapidly &
axonal sprouts grow from the proximal
stump, enter the distal stump, & grow toward the
nerve's end-organs
• if regeneration does not occur, the axon & the
Schwann cells are replaced by fibrous tissue
produced by local fibroblasts
Changes in the Proximal Segment of the Axon
• The changes in the proximal segment of the
axon are similar to those that take place in the
distal segment but extend only proximally above
the lesion as far as the first node of Ranvier
Changes in the nerve cell body
• The changes that occur in the cell body
following injury to its axon are referred to as
retrograde degeneration
• The Nissl material becomes
fine, granular, & dispersed throughout
the cytoplasm (chromatolysis)
• the nucleus moves toward the periphery of the
cell, & the cell body swells & becomes rounded
• Synaptic terminals are replaced by Schwann
cells in the PNS & microglial cells or astrocytes in
the CNS
Recovery of Neurons Following Injury
• the recovery of the nerve cell body &
regeneration of its processes may take several
months
Recovery of the Nerve Cell Body
• RNA & protein synthesis is
accelerated
• a reconstitution of the original Nissl structure
• a decrease in the swelling of the cell body
• a return of nucleus to its characteristic central position
Regeneration of Axons in Peripheral Nerves
• depend on endoneurial tubes & possessed by
Schwann cells
• The following mechanisms are involved:
1. the axons are attracted by chemotropic factors
secreted by the Schwann cells in the distal stump,
2. growth-stimulating factors exist within the distal
stump, &
3. inhibitory factors are present in the perineurium to
inhibit the axons from leaving the nerve
Regeneration of Axons in the CNS
• Central axons may not be as good at
regeneration as peripheral axons
• The regeneration process is aborted by
• failure of oligodendrocytes to serve in the same
manner as Schwann cells,
• laying down of scar tissue by the active astrocytes
• absence of nerve growth factors in the CNS
• neuroglial cells may produce nerve growth-inhibiting
factors
Nerve injury
References
• Clinical Neuroanatomy, 7/E Snell
• Essentials of Medical Physiology, 3/E Mahapatra
• Principles of Neural Science, 5/E Kandel ER,
Schwartz JH, Jessell TM (editors)
Thank You
Thank You

Más contenido relacionado

La actualidad más candente

La actualidad más candente (20)

Peripheral nerve injury
Peripheral nerve injuryPeripheral nerve injury
Peripheral nerve injury
 
Peripheral Nerve Repair
Peripheral Nerve RepairPeripheral Nerve Repair
Peripheral Nerve Repair
 
Pain gait theory
Pain gait theoryPain gait theory
Pain gait theory
 
Fracture healing
Fracture healing Fracture healing
Fracture healing
 
Pain gate theory
Pain gate theoryPain gate theory
Pain gate theory
 
Evaluating nerve injury and regeneration
Evaluating nerve injury and regenerationEvaluating nerve injury and regeneration
Evaluating nerve injury and regeneration
 
Carpal tunnel syndrome
Carpal tunnel syndromeCarpal tunnel syndrome
Carpal tunnel syndrome
 
classification and diagnostic methods of peripheral nerve injury
classification and diagnostic methods of peripheral nerve injuryclassification and diagnostic methods of peripheral nerve injury
classification and diagnostic methods of peripheral nerve injury
 
Tarsal tunnel syndrome
Tarsal tunnel syndromeTarsal tunnel syndrome
Tarsal tunnel syndrome
 
radial nerve palsy
radial nerve palsy radial nerve palsy
radial nerve palsy
 
Nerve repair and grafting
Nerve repair and graftingNerve repair and grafting
Nerve repair and grafting
 
Carpal tunnel syndrome
Carpal tunnel syndromeCarpal tunnel syndrome
Carpal tunnel syndrome
 
Spinal fractures (injury)
Spinal fractures (injury)Spinal fractures (injury)
Spinal fractures (injury)
 
Complications of fractures
Complications of fracturesComplications of fractures
Complications of fractures
 
Volksmann contracture
Volksmann contracture Volksmann contracture
Volksmann contracture
 
Lecture 2 Electrotherapy- pain physiology
Lecture 2  Electrotherapy- pain physiologyLecture 2  Electrotherapy- pain physiology
Lecture 2 Electrotherapy- pain physiology
 
Pain gate theory
Pain gate theoryPain gate theory
Pain gate theory
 
Spinal arachnoiditis
Spinal arachnoiditisSpinal arachnoiditis
Spinal arachnoiditis
 
Biology of nerve injury and repair
Biology of nerve injury and repairBiology of nerve injury and repair
Biology of nerve injury and repair
 
Gait normal & abnormal
Gait normal & abnormalGait normal & abnormal
Gait normal & abnormal
 

Destacado

Nerve injury and repair
Nerve injury and repairNerve injury and repair
Nerve injury and repairAkashah Ambar
 
Degeneration and regeneration of
Degeneration and regeneration ofDegeneration and regeneration of
Degeneration and regeneration ofM Sohail Raza
 
Hyperbaric Oxygen Therapy.
Hyperbaric Oxygen Therapy. Hyperbaric Oxygen Therapy.
Hyperbaric Oxygen Therapy. Sudarsan Agarwal
 
Ludwig’s angina
Ludwig’s anginaLudwig’s angina
Ludwig’s anginaHardik Vora
 
EVISCERATION, ENUCLEATION, EXENTRATION, CYCLODESTRUCTIVE PROCEDURES
EVISCERATION, ENUCLEATION, EXENTRATION, CYCLODESTRUCTIVE PROCEDURESEVISCERATION, ENUCLEATION, EXENTRATION, CYCLODESTRUCTIVE PROCEDURES
EVISCERATION, ENUCLEATION, EXENTRATION, CYCLODESTRUCTIVE PROCEDURESReshma Peter
 
Fascial space & infections
Fascial space & infectionsFascial space & infections
Fascial space & infectionsSurbhi Singh
 
Pre prosthetic surgery
Pre prosthetic surgeryPre prosthetic surgery
Pre prosthetic surgeryKrupa Mayekar
 
Principles of Exodontia
Principles of ExodontiaPrinciples of Exodontia
Principles of ExodontiaIAU Dent
 

Destacado (16)

Nerve injury and repair
Nerve injury and repairNerve injury and repair
Nerve injury and repair
 
Peripheral Nerve Injuries
Peripheral Nerve InjuriesPeripheral Nerve Injuries
Peripheral Nerve Injuries
 
Degeneration and regeneration of
Degeneration and regeneration ofDegeneration and regeneration of
Degeneration and regeneration of
 
Nerve injury
Nerve injuryNerve injury
Nerve injury
 
Hyperbaric Oxygen Therapy.
Hyperbaric Oxygen Therapy. Hyperbaric Oxygen Therapy.
Hyperbaric Oxygen Therapy.
 
Ludwig’s angina
Ludwig’s anginaLudwig’s angina
Ludwig’s angina
 
Dental elevators
Dental elevatorsDental elevators
Dental elevators
 
Pre Prosthetic Surgery
Pre Prosthetic SurgeryPre Prosthetic Surgery
Pre Prosthetic Surgery
 
EVISCERATION, ENUCLEATION, EXENTRATION, CYCLODESTRUCTIVE PROCEDURES
EVISCERATION, ENUCLEATION, EXENTRATION, CYCLODESTRUCTIVE PROCEDURESEVISCERATION, ENUCLEATION, EXENTRATION, CYCLODESTRUCTIVE PROCEDURES
EVISCERATION, ENUCLEATION, EXENTRATION, CYCLODESTRUCTIVE PROCEDURES
 
Hyperbaric oxygen therapy
Hyperbaric oxygen therapyHyperbaric oxygen therapy
Hyperbaric oxygen therapy
 
space infection
space infectionspace infection
space infection
 
Syncope
SyncopeSyncope
Syncope
 
Fascial space & infections
Fascial space & infectionsFascial space & infections
Fascial space & infections
 
Pre prosthetic surgery
Pre prosthetic surgeryPre prosthetic surgery
Pre prosthetic surgery
 
Dental Elevators
 Dental Elevators Dental Elevators
Dental Elevators
 
Principles of Exodontia
Principles of ExodontiaPrinciples of Exodontia
Principles of Exodontia
 

Similar a Nerve injury

Degeneration & regeneration of nerve fiber.ppt by Dr. PANDIAN M.
Degeneration & regeneration of nerve fiber.ppt by Dr. PANDIAN M.Degeneration & regeneration of nerve fiber.ppt by Dr. PANDIAN M.
Degeneration & regeneration of nerve fiber.ppt by Dr. PANDIAN M.Pandian M
 
Degeneration and regeneration of nerve fiber BY PANDIAN MTHIS PPT ONLY FIOR...
Degeneration and   regeneration of nerve fiber BY PANDIAN MTHIS PPT ONLY FIOR...Degeneration and   regeneration of nerve fiber BY PANDIAN MTHIS PPT ONLY FIOR...
Degeneration and regeneration of nerve fiber BY PANDIAN MTHIS PPT ONLY FIOR...Pandian M
 
Degenerationandregenerationof 151229165931
Degenerationandregenerationof 151229165931Degenerationandregenerationof 151229165931
Degenerationandregenerationof 151229165931mahmmud shuvale
 
Nerve Injuries and its management techniues.pptx
Nerve Injuries and its management techniues.pptxNerve Injuries and its management techniues.pptx
Nerve Injuries and its management techniues.pptxHanineHassan2
 
Neuroanatomy and physiology
Neuroanatomy and physiologyNeuroanatomy and physiology
Neuroanatomy and physiologyRekha Pathak
 
central nervous system
central nervous systemcentral nervous system
central nervous systemVenkeyReddy
 
Peripheral Nerve Injury: Radial Nerve Palsy
Peripheral Nerve Injury: Radial Nerve PalsyPeripheral Nerve Injury: Radial Nerve Palsy
Peripheral Nerve Injury: Radial Nerve PalsySijan Bhattachan
 
Peripheral nerve injuries-ASSESSMENT AND TENDON TRANSFERS IN RADIAL NERVE PALSY
Peripheral nerve injuries-ASSESSMENT AND TENDON TRANSFERS IN RADIAL NERVE PALSYPeripheral nerve injuries-ASSESSMENT AND TENDON TRANSFERS IN RADIAL NERVE PALSY
Peripheral nerve injuries-ASSESSMENT AND TENDON TRANSFERS IN RADIAL NERVE PALSYsuchitra_gmc
 
Introduction to periphral nervous sys
Introduction to periphral nervous sysIntroduction to periphral nervous sys
Introduction to periphral nervous sysHaneen Hassan
 
Degeneration and regeneration of nerve fibers
Degeneration and regeneration of nerve fibersDegeneration and regeneration of nerve fibers
Degeneration and regeneration of nerve fibersmariaidrees3
 
Lect 1 introduction to nerve
Lect 1 introduction to nerveLect 1 introduction to nerve
Lect 1 introduction to nerveAyub Abdi
 
Nerve Physiology
Nerve Physiology Nerve Physiology
Nerve Physiology Saran A K
 
Neuron structure and functions by Dr. Pandian M, Dept of Physiology, DYPMCK...
Neuron   structure and functions by Dr. Pandian M, Dept of Physiology, DYPMCK...Neuron   structure and functions by Dr. Pandian M, Dept of Physiology, DYPMCK...
Neuron structure and functions by Dr. Pandian M, Dept of Physiology, DYPMCK...Pandian M
 
Neuroplasticity and neurodegeneration
Neuroplasticity and neurodegenerationNeuroplasticity and neurodegeneration
Neuroplasticity and neurodegenerationAdonis Sfera, MD
 
Presentation[1].pptx
Presentation[1].pptxPresentation[1].pptx
Presentation[1].pptxFasihAsghar
 
Peripheral nerve injury
Peripheral nerve injuryPeripheral nerve injury
Peripheral nerve injuryFakhri Mnahi
 

Similar a Nerve injury (20)

Degeneration & regeneration of nerve fiber.ppt by Dr. PANDIAN M.
Degeneration & regeneration of nerve fiber.ppt by Dr. PANDIAN M.Degeneration & regeneration of nerve fiber.ppt by Dr. PANDIAN M.
Degeneration & regeneration of nerve fiber.ppt by Dr. PANDIAN M.
 
Degeneration and regeneration of nerve fiber BY PANDIAN MTHIS PPT ONLY FIOR...
Degeneration and   regeneration of nerve fiber BY PANDIAN MTHIS PPT ONLY FIOR...Degeneration and   regeneration of nerve fiber BY PANDIAN MTHIS PPT ONLY FIOR...
Degeneration and regeneration of nerve fiber BY PANDIAN MTHIS PPT ONLY FIOR...
 
Degenerationandregenerationof 151229165931
Degenerationandregenerationof 151229165931Degenerationandregenerationof 151229165931
Degenerationandregenerationof 151229165931
 
Nerve Injuries and its management techniues.pptx
Nerve Injuries and its management techniues.pptxNerve Injuries and its management techniues.pptx
Nerve Injuries and its management techniues.pptx
 
Neuroanatomy and physiology
Neuroanatomy and physiologyNeuroanatomy and physiology
Neuroanatomy and physiology
 
Pathology of nervous system
Pathology of nervous systemPathology of nervous system
Pathology of nervous system
 
Nervous System.pptx
Nervous System.pptxNervous System.pptx
Nervous System.pptx
 
central nervous system
central nervous systemcentral nervous system
central nervous system
 
Peripheral Nerve Injury: Radial Nerve Palsy
Peripheral Nerve Injury: Radial Nerve PalsyPeripheral Nerve Injury: Radial Nerve Palsy
Peripheral Nerve Injury: Radial Nerve Palsy
 
Peripheral nerve injuries-ASSESSMENT AND TENDON TRANSFERS IN RADIAL NERVE PALSY
Peripheral nerve injuries-ASSESSMENT AND TENDON TRANSFERS IN RADIAL NERVE PALSYPeripheral nerve injuries-ASSESSMENT AND TENDON TRANSFERS IN RADIAL NERVE PALSY
Peripheral nerve injuries-ASSESSMENT AND TENDON TRANSFERS IN RADIAL NERVE PALSY
 
Introduction to periphral nervous sys
Introduction to periphral nervous sysIntroduction to periphral nervous sys
Introduction to periphral nervous sys
 
Nervous System .pdf
Nervous System .pdfNervous System .pdf
Nervous System .pdf
 
PAIN AND PAIN PATHWAYS
PAIN AND PAIN PATHWAYSPAIN AND PAIN PATHWAYS
PAIN AND PAIN PATHWAYS
 
Degeneration and regeneration of nerve fibers
Degeneration and regeneration of nerve fibersDegeneration and regeneration of nerve fibers
Degeneration and regeneration of nerve fibers
 
Lect 1 introduction to nerve
Lect 1 introduction to nerveLect 1 introduction to nerve
Lect 1 introduction to nerve
 
Nerve Physiology
Nerve Physiology Nerve Physiology
Nerve Physiology
 
Neuron structure and functions by Dr. Pandian M, Dept of Physiology, DYPMCK...
Neuron   structure and functions by Dr. Pandian M, Dept of Physiology, DYPMCK...Neuron   structure and functions by Dr. Pandian M, Dept of Physiology, DYPMCK...
Neuron structure and functions by Dr. Pandian M, Dept of Physiology, DYPMCK...
 
Neuroplasticity and neurodegeneration
Neuroplasticity and neurodegenerationNeuroplasticity and neurodegeneration
Neuroplasticity and neurodegeneration
 
Presentation[1].pptx
Presentation[1].pptxPresentation[1].pptx
Presentation[1].pptx
 
Peripheral nerve injury
Peripheral nerve injuryPeripheral nerve injury
Peripheral nerve injury
 

Más de Rajesh Goit

Evoked potentials, clinical importance & physiological basis of consciousness...
Evoked potentials, clinical importance & physiological basis of consciousness...Evoked potentials, clinical importance & physiological basis of consciousness...
Evoked potentials, clinical importance & physiological basis of consciousness...Rajesh Goit
 
Blood brain barrier
Blood brain barrierBlood brain barrier
Blood brain barrierRajesh Goit
 
Origin and spread of cardiac impulse, pacemaker, conducting system of heart, ...
Origin and spread of cardiac impulse, pacemaker, conducting system of heart, ...Origin and spread of cardiac impulse, pacemaker, conducting system of heart, ...
Origin and spread of cardiac impulse, pacemaker, conducting system of heart, ...Rajesh Goit
 
Structure of cardiac muscle excitation contraction coupling properties of car...
Structure of cardiac muscle excitation contraction coupling properties of car...Structure of cardiac muscle excitation contraction coupling properties of car...
Structure of cardiac muscle excitation contraction coupling properties of car...Rajesh Goit
 
Electrocardiography
ElectrocardiographyElectrocardiography
ElectrocardiographyRajesh Goit
 
Neuromuscular transmission
Neuromuscular transmissionNeuromuscular transmission
Neuromuscular transmissionRajesh Goit
 
Muscles classification
Muscles classificationMuscles classification
Muscles classificationRajesh Goit
 
Muscle contraction
Muscle contractionMuscle contraction
Muscle contractionRajesh Goit
 
Isotonic & isometric contraction
Isotonic & isometric contractionIsotonic & isometric contraction
Isotonic & isometric contractionRajesh Goit
 
Factors influencing force of contracton
Factors influencing force of contractonFactors influencing force of contracton
Factors influencing force of contractonRajesh Goit
 
Electromyography
ElectromyographyElectromyography
ElectromyographyRajesh Goit
 
Introduction of gastrointestinal tract
Introduction of gastrointestinal tractIntroduction of gastrointestinal tract
Introduction of gastrointestinal tractRajesh Goit
 
Gastrointestinal hormomes & their role in secretomotor fuction of the gut
Gastrointestinal hormomes & their role in secretomotor fuction of the gutGastrointestinal hormomes & their role in secretomotor fuction of the gut
Gastrointestinal hormomes & their role in secretomotor fuction of the gutRajesh Goit
 
Functions of spleen and lymph nodes
Functions of spleen and lymph nodesFunctions of spleen and lymph nodes
Functions of spleen and lymph nodesRajesh Goit
 

Más de Rajesh Goit (16)

Hemostasis
HemostasisHemostasis
Hemostasis
 
Reflexes
ReflexesReflexes
Reflexes
 
Evoked potentials, clinical importance & physiological basis of consciousness...
Evoked potentials, clinical importance & physiological basis of consciousness...Evoked potentials, clinical importance & physiological basis of consciousness...
Evoked potentials, clinical importance & physiological basis of consciousness...
 
Blood brain barrier
Blood brain barrierBlood brain barrier
Blood brain barrier
 
Origin and spread of cardiac impulse, pacemaker, conducting system of heart, ...
Origin and spread of cardiac impulse, pacemaker, conducting system of heart, ...Origin and spread of cardiac impulse, pacemaker, conducting system of heart, ...
Origin and spread of cardiac impulse, pacemaker, conducting system of heart, ...
 
Structure of cardiac muscle excitation contraction coupling properties of car...
Structure of cardiac muscle excitation contraction coupling properties of car...Structure of cardiac muscle excitation contraction coupling properties of car...
Structure of cardiac muscle excitation contraction coupling properties of car...
 
Electrocardiography
ElectrocardiographyElectrocardiography
Electrocardiography
 
Neuromuscular transmission
Neuromuscular transmissionNeuromuscular transmission
Neuromuscular transmission
 
Muscles classification
Muscles classificationMuscles classification
Muscles classification
 
Muscle contraction
Muscle contractionMuscle contraction
Muscle contraction
 
Isotonic & isometric contraction
Isotonic & isometric contractionIsotonic & isometric contraction
Isotonic & isometric contraction
 
Factors influencing force of contracton
Factors influencing force of contractonFactors influencing force of contracton
Factors influencing force of contracton
 
Electromyography
ElectromyographyElectromyography
Electromyography
 
Introduction of gastrointestinal tract
Introduction of gastrointestinal tractIntroduction of gastrointestinal tract
Introduction of gastrointestinal tract
 
Gastrointestinal hormomes & their role in secretomotor fuction of the gut
Gastrointestinal hormomes & their role in secretomotor fuction of the gutGastrointestinal hormomes & their role in secretomotor fuction of the gut
Gastrointestinal hormomes & their role in secretomotor fuction of the gut
 
Functions of spleen and lymph nodes
Functions of spleen and lymph nodesFunctions of spleen and lymph nodes
Functions of spleen and lymph nodes
 

Último

Physiology of Smooth Muscles -Mechanics of contraction and relaxation
Physiology of Smooth Muscles -Mechanics of contraction and relaxationPhysiology of Smooth Muscles -Mechanics of contraction and relaxation
Physiology of Smooth Muscles -Mechanics of contraction and relaxationMedicoseAcademics
 
"Radical excision of DIE in subferile women with deep infiltrating endometrio...
"Radical excision of DIE in subferile women with deep infiltrating endometrio..."Radical excision of DIE in subferile women with deep infiltrating endometrio...
"Radical excision of DIE in subferile women with deep infiltrating endometrio...Sujoy Dasgupta
 
SGK RỐI LOẠN KALI MÁU CỰC KỲ QUAN TRỌNG.pdf
SGK RỐI LOẠN KALI MÁU CỰC KỲ QUAN TRỌNG.pdfSGK RỐI LOẠN KALI MÁU CỰC KỲ QUAN TRỌNG.pdf
SGK RỐI LOẠN KALI MÁU CỰC KỲ QUAN TRỌNG.pdfHongBiThi1
 
Red Blood Cells_anemia & polycythemia.pdf
Red Blood Cells_anemia & polycythemia.pdfRed Blood Cells_anemia & polycythemia.pdf
Red Blood Cells_anemia & polycythemia.pdfMedicoseAcademics
 
PAIN/CLASSIFICATION AND MANAGEMENT OF PAIN.pdf
PAIN/CLASSIFICATION AND MANAGEMENT OF PAIN.pdfPAIN/CLASSIFICATION AND MANAGEMENT OF PAIN.pdf
PAIN/CLASSIFICATION AND MANAGEMENT OF PAIN.pdfDolisha Warbi
 
FDMA FLAP - The first dorsal metacarpal artery (FDMA) flap is used mainly for...
FDMA FLAP - The first dorsal metacarpal artery (FDMA) flap is used mainly for...FDMA FLAP - The first dorsal metacarpal artery (FDMA) flap is used mainly for...
FDMA FLAP - The first dorsal metacarpal artery (FDMA) flap is used mainly for...Shubhanshu Gaurav
 
Male Infertility, Antioxidants and Beyond
Male Infertility, Antioxidants and BeyondMale Infertility, Antioxidants and Beyond
Male Infertility, Antioxidants and BeyondSujoy Dasgupta
 
blood bank management system project report
blood bank management system project reportblood bank management system project report
blood bank management system project reportNARMADAPETROLEUMGAS
 
High-Performance Thin-Layer Chromatography (HPTLC)
High-Performance Thin-Layer Chromatography (HPTLC)High-Performance Thin-Layer Chromatography (HPTLC)
High-Performance Thin-Layer Chromatography (HPTLC)kishan singh tomar
 
Bulimia nervosa ( Eating Disorders) Mental Health Nursing.
Bulimia nervosa ( Eating Disorders) Mental Health Nursing.Bulimia nervosa ( Eating Disorders) Mental Health Nursing.
Bulimia nervosa ( Eating Disorders) Mental Health Nursing.aarjukhadka22
 
Unit I herbs as raw materials, biodynamic agriculture.ppt
Unit I herbs as raw materials, biodynamic agriculture.pptUnit I herbs as raw materials, biodynamic agriculture.ppt
Unit I herbs as raw materials, biodynamic agriculture.pptPradnya Wadekar
 
SGK RỐI LOẠN TOAN KIỀM ĐHYHN RẤT HAY VÀ ĐẶC SẮC.pdf
SGK RỐI LOẠN TOAN KIỀM ĐHYHN RẤT HAY VÀ ĐẶC SẮC.pdfSGK RỐI LOẠN TOAN KIỀM ĐHYHN RẤT HAY VÀ ĐẶC SẮC.pdf
SGK RỐI LOẠN TOAN KIỀM ĐHYHN RẤT HAY VÀ ĐẶC SẮC.pdfHongBiThi1
 
MedMatch: Your Health, Our Mission. Pitch deck.
MedMatch: Your Health, Our Mission. Pitch deck.MedMatch: Your Health, Our Mission. Pitch deck.
MedMatch: Your Health, Our Mission. Pitch deck.whalesdesign
 
How to cure cirrhosis and chronic hepatitis naturally
How to cure cirrhosis and chronic hepatitis naturallyHow to cure cirrhosis and chronic hepatitis naturally
How to cure cirrhosis and chronic hepatitis naturallyZurück zum Ursprung
 
Breast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptx
Breast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptxBreast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptx
Breast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptxNaveenkumar267201
 
CONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdf
CONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdfCONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdf
CONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdfDolisha Warbi
 
ANATOMICAL FAETURES OF BONES FOR NURSING STUDENTS .pptx
ANATOMICAL FAETURES OF BONES  FOR NURSING STUDENTS .pptxANATOMICAL FAETURES OF BONES  FOR NURSING STUDENTS .pptx
ANATOMICAL FAETURES OF BONES FOR NURSING STUDENTS .pptxWINCY THIRUMURUGAN
 
Female Reproductive Physiology Before Pregnancy
Female Reproductive Physiology Before PregnancyFemale Reproductive Physiology Before Pregnancy
Female Reproductive Physiology Before PregnancyMedicoseAcademics
 
Neurological history taking (2024) .
Neurological  history  taking  (2024)  .Neurological  history  taking  (2024)  .
Neurological history taking (2024) .Mohamed Rizk Khodair
 

Último (20)

Physiology of Smooth Muscles -Mechanics of contraction and relaxation
Physiology of Smooth Muscles -Mechanics of contraction and relaxationPhysiology of Smooth Muscles -Mechanics of contraction and relaxation
Physiology of Smooth Muscles -Mechanics of contraction and relaxation
 
"Radical excision of DIE in subferile women with deep infiltrating endometrio...
"Radical excision of DIE in subferile women with deep infiltrating endometrio..."Radical excision of DIE in subferile women with deep infiltrating endometrio...
"Radical excision of DIE in subferile women with deep infiltrating endometrio...
 
SGK RỐI LOẠN KALI MÁU CỰC KỲ QUAN TRỌNG.pdf
SGK RỐI LOẠN KALI MÁU CỰC KỲ QUAN TRỌNG.pdfSGK RỐI LOẠN KALI MÁU CỰC KỲ QUAN TRỌNG.pdf
SGK RỐI LOẠN KALI MÁU CỰC KỲ QUAN TRỌNG.pdf
 
Red Blood Cells_anemia & polycythemia.pdf
Red Blood Cells_anemia & polycythemia.pdfRed Blood Cells_anemia & polycythemia.pdf
Red Blood Cells_anemia & polycythemia.pdf
 
PAIN/CLASSIFICATION AND MANAGEMENT OF PAIN.pdf
PAIN/CLASSIFICATION AND MANAGEMENT OF PAIN.pdfPAIN/CLASSIFICATION AND MANAGEMENT OF PAIN.pdf
PAIN/CLASSIFICATION AND MANAGEMENT OF PAIN.pdf
 
Rheumatoid arthritis Part 1, case based approach with application of the late...
Rheumatoid arthritis Part 1, case based approach with application of the late...Rheumatoid arthritis Part 1, case based approach with application of the late...
Rheumatoid arthritis Part 1, case based approach with application of the late...
 
FDMA FLAP - The first dorsal metacarpal artery (FDMA) flap is used mainly for...
FDMA FLAP - The first dorsal metacarpal artery (FDMA) flap is used mainly for...FDMA FLAP - The first dorsal metacarpal artery (FDMA) flap is used mainly for...
FDMA FLAP - The first dorsal metacarpal artery (FDMA) flap is used mainly for...
 
Male Infertility, Antioxidants and Beyond
Male Infertility, Antioxidants and BeyondMale Infertility, Antioxidants and Beyond
Male Infertility, Antioxidants and Beyond
 
blood bank management system project report
blood bank management system project reportblood bank management system project report
blood bank management system project report
 
High-Performance Thin-Layer Chromatography (HPTLC)
High-Performance Thin-Layer Chromatography (HPTLC)High-Performance Thin-Layer Chromatography (HPTLC)
High-Performance Thin-Layer Chromatography (HPTLC)
 
Bulimia nervosa ( Eating Disorders) Mental Health Nursing.
Bulimia nervosa ( Eating Disorders) Mental Health Nursing.Bulimia nervosa ( Eating Disorders) Mental Health Nursing.
Bulimia nervosa ( Eating Disorders) Mental Health Nursing.
 
Unit I herbs as raw materials, biodynamic agriculture.ppt
Unit I herbs as raw materials, biodynamic agriculture.pptUnit I herbs as raw materials, biodynamic agriculture.ppt
Unit I herbs as raw materials, biodynamic agriculture.ppt
 
SGK RỐI LOẠN TOAN KIỀM ĐHYHN RẤT HAY VÀ ĐẶC SẮC.pdf
SGK RỐI LOẠN TOAN KIỀM ĐHYHN RẤT HAY VÀ ĐẶC SẮC.pdfSGK RỐI LOẠN TOAN KIỀM ĐHYHN RẤT HAY VÀ ĐẶC SẮC.pdf
SGK RỐI LOẠN TOAN KIỀM ĐHYHN RẤT HAY VÀ ĐẶC SẮC.pdf
 
MedMatch: Your Health, Our Mission. Pitch deck.
MedMatch: Your Health, Our Mission. Pitch deck.MedMatch: Your Health, Our Mission. Pitch deck.
MedMatch: Your Health, Our Mission. Pitch deck.
 
How to cure cirrhosis and chronic hepatitis naturally
How to cure cirrhosis and chronic hepatitis naturallyHow to cure cirrhosis and chronic hepatitis naturally
How to cure cirrhosis and chronic hepatitis naturally
 
Breast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptx
Breast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptxBreast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptx
Breast cancer -ONCO IN MEDICAL AND SURGICAL NURSING.pptx
 
CONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdf
CONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdfCONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdf
CONNECTIVE TISSUE (ANATOMY AND PHYSIOLOGY).pdf
 
ANATOMICAL FAETURES OF BONES FOR NURSING STUDENTS .pptx
ANATOMICAL FAETURES OF BONES  FOR NURSING STUDENTS .pptxANATOMICAL FAETURES OF BONES  FOR NURSING STUDENTS .pptx
ANATOMICAL FAETURES OF BONES FOR NURSING STUDENTS .pptx
 
Female Reproductive Physiology Before Pregnancy
Female Reproductive Physiology Before PregnancyFemale Reproductive Physiology Before Pregnancy
Female Reproductive Physiology Before Pregnancy
 
Neurological history taking (2024) .
Neurological  history  taking  (2024)  .Neurological  history  taking  (2024)  .
Neurological history taking (2024) .
 

Nerve injury

  • 1. Response of neurons & nerve fibers to injury Types of injury Wallerian degeneration, regeneration & Factors for regeneration RK Goit, Lecturer Department of Physiology
  • 2. • Neuron is the basic function unit of the nervous system. • In the mature human, if it is destroyed, it is not replaced. • It may be injured due to various reasons(cutting, crushing, pull & pressure). • These injuries may damage a nerve variously & the injury is classified according to the extent of the damage.
  • 5. Seddon (1944) described 3 clinical types of nerve injury: • Neurapraxia (Class I) • the term applied to a transient block • paralysis is incomplete, recovery is rapid & complete, & there is no nerve degeneration • pressure is the most common cause • Axonotmesis (Class II) • the term applied to a nerve lesion in which the axons are damaged but the surrounding connective tissue sheaths remain intact • Wallerian degeneration occurs peripherally • functional recovery is more rapid & more complete than after complete section of the nerve trunk • crush injuries, traction, & compression are the most common causes
  • 6. • Neurotmesis (Class III) • the term applied to complete section of the nerve trunk • occur on severe contusion, stretch, laceration Sunderland (1951) expanded Seddon’s classification to 5 degrees: • First-degree (Class I) • Seddon’s neurapraxia & first-degree are the same • Second-degree (Class II) • Seddon’s axonotmesis & second-degree are the same
  • 7. • Third-degree (Class II) • nerve fiber interruption • there is a lesion of the endoneurium, but the epineurium & perineurium remain intact • recovery from a third-degree injury is possible, but surgical intervention may be required • Fourth-degree (Class II) • only the epineurium remain intact • surgical repair is required • Fifth-degree (Class III) • lesion of complete transection of the nerve • Recovery is not possible without an appropriate surgical treatment
  • 9. Injury of the Nerve Cell Body • Severe damage of the nerve cell body may result in degeneration of the entire neuron • In the CNS, the tissue macrophages (microglial cells) remove the debris, & the neighboring astrocytes replace the neuron with scar tissue • In the PNS, the tissue macrophages remove the debris, & the local fibroblasts replace the neuron with scar tissue
  • 10. Injury of the Nerve Cell Process • if the axon of the nerve cell is divided, degenerative changes will take place in 1. distal segment of the axon 2. a portion of the axon proximal to the injury 3. the cell body from which the axon arises
  • 11. Changes in the Distal Segment of the Axon • wallerian degeneration is the changes that occur distally to the site of damage on an axon • axon becomes swollen & irregular; the axon is broken into fragments, & the debris is digested by surrounding Schwann cells & tissue macrophages • entire axon is destroyed within a week
  • 12. • myelin sheath is converted into lipid droplets • the droplets are extruded from the Schwann cell & subsequently are phagocytosed by tissue macrophages • Schwann cells now begin to proliferate rapidly & axonal sprouts grow from the proximal stump, enter the distal stump, & grow toward the nerve's end-organs • if regeneration does not occur, the axon & the Schwann cells are replaced by fibrous tissue produced by local fibroblasts
  • 13. Changes in the Proximal Segment of the Axon • The changes in the proximal segment of the axon are similar to those that take place in the distal segment but extend only proximally above the lesion as far as the first node of Ranvier
  • 14. Changes in the nerve cell body • The changes that occur in the cell body following injury to its axon are referred to as retrograde degeneration • The Nissl material becomes fine, granular, & dispersed throughout the cytoplasm (chromatolysis) • the nucleus moves toward the periphery of the cell, & the cell body swells & becomes rounded • Synaptic terminals are replaced by Schwann cells in the PNS & microglial cells or astrocytes in the CNS
  • 15. Recovery of Neurons Following Injury • the recovery of the nerve cell body & regeneration of its processes may take several months Recovery of the Nerve Cell Body • RNA & protein synthesis is accelerated • a reconstitution of the original Nissl structure • a decrease in the swelling of the cell body • a return of nucleus to its characteristic central position
  • 16. Regeneration of Axons in Peripheral Nerves • depend on endoneurial tubes & possessed by Schwann cells • The following mechanisms are involved: 1. the axons are attracted by chemotropic factors secreted by the Schwann cells in the distal stump, 2. growth-stimulating factors exist within the distal stump, & 3. inhibitory factors are present in the perineurium to inhibit the axons from leaving the nerve
  • 17. Regeneration of Axons in the CNS • Central axons may not be as good at regeneration as peripheral axons • The regeneration process is aborted by • failure of oligodendrocytes to serve in the same manner as Schwann cells, • laying down of scar tissue by the active astrocytes • absence of nerve growth factors in the CNS • neuroglial cells may produce nerve growth-inhibiting factors
  • 19. References • Clinical Neuroanatomy, 7/E Snell • Essentials of Medical Physiology, 3/E Mahapatra • Principles of Neural Science, 5/E Kandel ER, Schwartz JH, Jessell TM (editors) Thank You