This document discusses various types of reflexes in the human body. It begins by defining a reflex as a sudden involuntary response to a stimulus that involves a reflex arc. Reflex arcs consist of receptors, afferent neurons, centers in the CNS, efferent neurons, and effector organs. Reflexes are then classified based on the number of synapses (monosynaptic, bisynaptic, polysynaptic) and whether they are superficial, deep, or visceral. Specific reflexes discussed in detail include the stretch reflex, inverse stretch reflex, and reciprocal innervation. The stretch reflex is a monosynaptic reflex that causes muscle contraction when a muscle is stretched, while the inverse stretch reflex is bisynaptic and causes relaxation
Properties of nerve fiber by Pandian M, Dept Physiology DYPMCKOP, this ppt fo...Pandian M
Describe the types, functions & properties of nerve fibres
3.2.1 Classify nerve fibres
3.2.2 Classify nerve fibres based on the diameter & conduction velocity
3.2.3 Describe the salient features of Erlanger & Gasser
classification of nerve fibres
3.2.4 State the functions of type A, B & C nerve fibres
3.2.5 Compare & contrast the numerical classification with the
Erlanger & Gasser classification in the sensory nerve fibres
Properties of nerve fiber by Pandian M, Dept Physiology DYPMCKOP, this ppt fo...Pandian M
Describe the types, functions & properties of nerve fibres
3.2.1 Classify nerve fibres
3.2.2 Classify nerve fibres based on the diameter & conduction velocity
3.2.3 Describe the salient features of Erlanger & Gasser
classification of nerve fibres
3.2.4 State the functions of type A, B & C nerve fibres
3.2.5 Compare & contrast the numerical classification with the
Erlanger & Gasser classification in the sensory nerve fibres
Reflexes are important to understand for all medical professional it is an assessment tool for patients with neurological conditions.
a god knowledge of primitive reflexes can be effective for pediatric health care as well. it helps us in identifying any developmental delay in children.
Spasticity is a common motor control disorder frequently encountered in the
spectrum of the upper motor neuron (UMN) syndrome. It can result in pain,
fatigue, joint restrictions, functional impairments, and skin breakdown that may
negatively affect many domains of life by causing social avoidance and
diminished life satisfaction . Spasticity was originally defined as a velocity dependent increase in tonic stretch reflexes or muscle tone with exaggerated
tendon jerks resulting from increased excitability of the stretch reflex . This
definition has been criticized for being too narrow and inadequately depicting
the clinical sequelae. In 2005, a European Thematic Network to Develop
Standardized Measures of Spasticity (the SPASM consortium) suggested
broadening the definition to reflect a more clinical entity . They defined
spasticity as “disordered sensory-motor control, resulting from an upper motor
neuron lesion, presenting as intermittent or sustained involuntary activation of
muscles.
Reflex activity is the response to a peripheral stimulation that occurs without our consciousness.
Is an involuntary response to a stimulus.
It is a type of protective mechanism.
Principles and Methods of Heart Rate Variability BiofeedbackSaran A K
Biofeedback is a type of therapy that teaches a person to change and control physiological processes through practice.
Heart Rate Variability is a specific type of biofeedback that noninvasively measures harmony of autonomic nervous system.
Stress, anxiety, and maladaptive thought patterns result in incoherence.
With practice and guided exercises, individuals can utilize techniques to improve self-regulation and psychosocial functioning.
Empowers patient to be their own agent for change.
Vagus nerve stimulation involves using a device to stimulate the vagus nerve with electrical impulses. There's one vagus nerve on each side of your body. The vagus nerve runs from the lower part of the brain through the neck to the chest and stomach. When the vagus nerve is stimulated, electrical impulses travel to areas of the brain. This alters brain activity to treat certain conditions.
Vagus nerve stimulation can be done in many ways with many devices. An implantable vagus nerve stimulator has been approved by the Food and Drug Administration (FDA) to treat epilepsy and depression. The device works by sending stimulation to areas of the brain that lead to seizures and affect mood.
Reflexes are important to understand for all medical professional it is an assessment tool for patients with neurological conditions.
a god knowledge of primitive reflexes can be effective for pediatric health care as well. it helps us in identifying any developmental delay in children.
Spasticity is a common motor control disorder frequently encountered in the
spectrum of the upper motor neuron (UMN) syndrome. It can result in pain,
fatigue, joint restrictions, functional impairments, and skin breakdown that may
negatively affect many domains of life by causing social avoidance and
diminished life satisfaction . Spasticity was originally defined as a velocity dependent increase in tonic stretch reflexes or muscle tone with exaggerated
tendon jerks resulting from increased excitability of the stretch reflex . This
definition has been criticized for being too narrow and inadequately depicting
the clinical sequelae. In 2005, a European Thematic Network to Develop
Standardized Measures of Spasticity (the SPASM consortium) suggested
broadening the definition to reflect a more clinical entity . They defined
spasticity as “disordered sensory-motor control, resulting from an upper motor
neuron lesion, presenting as intermittent or sustained involuntary activation of
muscles.
Reflex activity is the response to a peripheral stimulation that occurs without our consciousness.
Is an involuntary response to a stimulus.
It is a type of protective mechanism.
Principles and Methods of Heart Rate Variability BiofeedbackSaran A K
Biofeedback is a type of therapy that teaches a person to change and control physiological processes through practice.
Heart Rate Variability is a specific type of biofeedback that noninvasively measures harmony of autonomic nervous system.
Stress, anxiety, and maladaptive thought patterns result in incoherence.
With practice and guided exercises, individuals can utilize techniques to improve self-regulation and psychosocial functioning.
Empowers patient to be their own agent for change.
Vagus nerve stimulation involves using a device to stimulate the vagus nerve with electrical impulses. There's one vagus nerve on each side of your body. The vagus nerve runs from the lower part of the brain through the neck to the chest and stomach. When the vagus nerve is stimulated, electrical impulses travel to areas of the brain. This alters brain activity to treat certain conditions.
Vagus nerve stimulation can be done in many ways with many devices. An implantable vagus nerve stimulator has been approved by the Food and Drug Administration (FDA) to treat epilepsy and depression. The device works by sending stimulation to areas of the brain that lead to seizures and affect mood.
Brief Overview of Autonomic Function TestsSaran A K
For most of us, stress maybe be a exam, a presentation or some personal goal you are working on. Stress is a word with broad meaning and is part and parcel of our day to day life. Now lets think or a patient with say, orthostatic hypotension, the mere act of standing up from a chair is a stress that he gives to the body. So regardless of whatever the stressor is, there is a system in our body which works tirelessly day after night in the background, that carefully orchestrates the body machinery to meet the challenges we throw at it. That strives for the golden state, that we physiologists love , homeostasis or the maintenance of milieu interior. That system to which we should be thankful to is the autonomic system.
Now in this presentation, we will talk about it but mainly about a brief overview of the autonomic function tests that are used for its assessment.
DM Seminar on Polysomnography. Sleep in itself is a myriad of wonders. In this presentation, we take a look at the neurobiology of sleep and how it is regulated in the human body. We also take a sneak peak into polysomnography as a window for monitoring sleep.
Sleep in itself is a myriad of wonders. In this presentation, we take a look at the neurobiology of sleep and how it is regulated in the human body. We also take a sneak peak into polysomnography as a window for monitoring sleep.
COVID 19 pandemic have had devastating impact on all aspects of life especially on the health systems. Back in March 2020, there was a war time emergency to scale up heath facilities in view of saving life without taxing the system. In response to the heavy patient load experienced at GMC, Calicut, NIT-K Mega Boys Hostel located 20 kms away from GMC Calicut was converted into a 500 bedded first line treatment centre within a short deadline of one week.
An oral paper presentation on the topic "Cardiorespiratory fitness: A cross-sectional study by comparison of the athletic and non-athletic medical UG students using VO2 max" based on the post graduate dissertation done in 2019-2021
Shear stress Effects on Left Coronary Artery Saran A K
Throughout the last decade, many studies have found the effect of shear stress on coronary vasculature. Ischaemic Heart Disease is a leading cause of death worldwide, killing an Indian every minute. The most common cause of myocardial ischemia is Atherosclerosis and on the basis of several data, atherosclerosis appears to be more prevalent in the left coronary arterial system compared to the right. The reason for this has remained an enigma for a long while but can be explained by using shear stress. Now, we will see how the shear stress breaks the coronary circuit
The blood circulates in a closed system of branching conduits. Haemodynamics refers to the studies of blood flow and related forces in moving the blood through the circulatory system. It
discusses the physical principles of blood flow t through the blood vessels with reference to the interrelationships among pressure, flow, and resistance.
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.
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 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
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.
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.
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.
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
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
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
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
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.
- 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
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
2. DEPT. OF PHYSIOLOGY, GMCM 3
Specific Learning Objectives
• Reflex
• Reflex Arc
• Classification of Reflex
• Stretch Reflex
• Inverse Stretch Reflex
• Reciprocal Innervation
• Withdrawal Reflex
• Properties of Reflexes
• Summary
DEPT. OF PHYSIOLOGY, GMCM
3. The sudden and involuntary response to a stimuli is
called a reflex.
DEPT. OF PHYSIOLOGY, GMCM 4
4. • It is a mechanism by which a sensory impulse is
automatically converted into a motor effect through
the involvement of CNS.
• It is mediated at the subcortical level and does not
involve the cerebral cortex.
DEPT. OF PHYSIOLOGY, GMCM 5
5. Specific Learning Objectives
• Reflex
• Reflex Arc
• Classification of Reflex
• Stretch Reflex
• Inverse Stretch Reflex
• Reciprocal Innervation
• Withdrawal Reflex
• Properties of Reflexes
• Summary
DEPT. OF PHYSIOLOGY, GMCM 6
DEPT. OF PHYSIOLOGY, GMCM
6. The basic unit of an integrated reflex activity is the
reflex arc.
DEPT. OF PHYSIOLOGY, GMCM 7
7. The arc consists of
1. Receptor
2. Afferent neuron
3. Centre – one or more synapses
4. Efferent neuron
5. Effector organ
Afferent Limb
Efferent Limb
DEPT. OF PHYSIOLOGY, GMCM 8
9. Afferent neuron carries sensory input from receptor
to center.
• Afferent neurons enter the centre in dorsal roots of
spinal nerves or cranial nerves.
• Have their cell bodies in DRG or in homologous
ganglia on cranial nerves.
DEPT. OF PHYSIOLOGY, GMCM 10
10. Centre is the part where connection between afferent
and efferent somatic neurons occur- integrating
region
• One or more synapses
• Generally, in brain or spinal cord.
DEPT. OF PHYSIOLOGY, GMCM 11
11. Efferent nerve transmit motor impulses from center to
effector organ.
• Efferent fibers leave via ventral roots or corresponding
motor cranial nerves.
DEPT. OF PHYSIOLOGY, GMCM 12
12. Bell –Magendie law
The principle that in spinal cord the dorsal roots are
sensory and ventral roots are motor is known as Bell
–Magendie law.
DEPT. OF PHYSIOLOGY, GMCM 13
14. Activity in a Reflex Arc
DEPT. OF PHYSIOLOGY, GMCM 15
15. Activity in the reflex arc starts in a sensory receptor with a
receptor potential whose magnitude is proportionate
to the strength of the stimulus (graded).
DEPT. OF PHYSIOLOGY, GMCM 16
16. Activity in a Reflex Arc
DEPT. OF PHYSIOLOGY, GMCM 17
22. Activity in a Reflex Arc
DEPT. OF PHYSIOLOGY, GMCM 23
23. When these reach the effector, they again set up a graded
response, the end plate potential.
DEPT. OF PHYSIOLOGY, GMCM 24
24. Activity in a Reflex Arc
DEPT. OF PHYSIOLOGY, GMCM 25
25. Specific Learning Objectives
• Reflex
• Reflex Arc
• Classification of Reflex
• Stretch Reflex
• Inverse Stretch Reflex
• Reciprocal Innervation
• Withdrawal Reflex
• Properties of Reflexes
• Summary
DEPT. OF PHYSIOLOGY, GMCM 26
DEPT. OF PHYSIOLOGY, GMCM
26. Classification of Reflex
1. Depending on the number of synapses between
afferent and efferent neurons
a. Monosynaptic Reflex
b. Bisynaptic Reflex
c. Polysynaptic Reflex
DEPT. OF PHYSIOLOGY, GMCM 27
27. a. Monosynaptic Reflex Arc
• Simplest reflex arc
• Single synapse between afferent & efferent neurons
• e.g. stretch reflex
DEPT. OF PHYSIOLOGY, GMCM 28
29. b. Bisynaptic or Disynaptic reflex
• Two synapses between afferent and efferent neuron
• e.g. Inverse stretch reflex , reciprocal innervation
DEPT. OF PHYSIOLOGY, GMCM 30
31. c. Polysynaptic reflex arc
• Reflex arc in which one or more interneurons are
interposed between afferent and efferent neurons
• Number of synapses in the arc vary from 2 to many
hundreds.
• e.g. Withdrawal reflex
DEPT. OF PHYSIOLOGY, GMCM 32
33. a. Monosynaptic
• Stretch Reflex
b. Bisynaptic Reflex (2 synapses)
• Inverse Stretch Reflex, Reciprocal Innervation
c. Polysynaptic Reflex (upto 100 synapses)
• Withdrawal Reflex, Superficial Reflexes
e.g.
DEPT. OF PHYSIOLOGY, GMCM 34
34. 2. Clinical Classification
a. Superficial Reflexes – elicited by stimulating skin or
mucus membrane. e.g.
Conjunctival Reflex
Corneal Reflex
Abdominal Reflex
Plantar Reflex
DEPT. OF PHYSIOLOGY, GMCM 35
35. b. Deep reflexes – basically stretch reflexes, elicited by
striking tendon of muscle
• cause stretching of the muscle
• results in contraction of the same muscle
e.g. biceps jerk, knee jerk, ankle jerk
DEPT. OF PHYSIOLOGY, GMCM 36
36. c. Visceral Reflex
e.g.
• Baroreceptor reflex
• Micturition reflex
• Defecation reflex
DEPT. OF PHYSIOLOGY, GMCM 37
37. d. Pathological Reflexes
Reflexes found only in pathological states
e.g.
Babinski’s sign (extensor plantar response)
DEPT. OF PHYSIOLOGY, GMCM 38
38. 3. Based on development
a. Unconditioned / Inborn – present at the time of birth
b. Conditioned /Acquired reflex – develops after birth,
acquired by training or experience
DEPT. OF PHYSIOLOGY, GMCM 39
39. Specific Learning Objectives
• Reflex
• Reflex Arc
• Classification of Reflex
• Stretch Reflex
• Inverse Stretch Reflex
• Reciprocal Innervation
• Withdrawal Reflex
• Properties of Reflexes
• Summary
DEPT. OF PHYSIOLOGY, GMCM 40
DEPT. OF PHYSIOLOGY, GMCM
40. Stretch Reflex
• When a skeletal muscle with an intact nerve supply is
stretched, it contracts.
• This response is called the stretch reflex.
• Sense organ – muscle spindle
DEPT. OF PHYSIOLOGY, GMCM 41
41. • Muscle spindle is a small encapsulated spindle like
structure located within fleshy part of muscle.
• Intrafusal muscle fiber- send information to CNS about
muscle length or rate of change of length.
DEPT. OF PHYSIOLOGY, GMCM 42
43. 1. Stimulus - stretch of the muscle
2. Sense organ / receptor - muscle spindle (intrafusal)
3. Afferent nerve – group Ia fibre
4. Centre – spinal cord (alpha motor neuron)
DEPT. OF PHYSIOLOGY, GMCM 44
44. 5. Efferent nerve – axons of alpha motor neuron
6. Effector organ – extrafusal muscle fibres
7. Effect- contraction of same muscle
DEPT. OF PHYSIOLOGY, GMCM 45
45. Stretch Reflex is an example of monosynaptic reflex.
DEPT. OF PHYSIOLOGY, GMCM 46
46. • Typical example – Knee jerk
• Tapping on patellar tendon
(Quadriceps muscle) with a
knee hammer stretches the
muscle
• Response – extension of knee
• Centre - L2, L3 and L4
DEPT. OF PHYSIOLOGY, GMCM 47
48. Reaction time
The time between the application of stimulus and the
response.
For knee jerk , it is 19 – 24 milliseconds
DEPT. OF PHYSIOLOGY, GMCM 49
49. This includes
• Time taken for impulse to traverse the afferent and
efferent fibers –Conduction time
• Central delay –Time taken for reflex activity to traverse
the spinal cord
DEPT. OF PHYSIOLOGY, GMCM 50
50. Conduction time can be calculated from
• Conduction velocity in Afferent and Efferent fibers
• Distance from muscle to spinal cord
• V= L/t
DEPT. OF PHYSIOLOGY, GMCM 51
51. Central Delay is 0.6-0.9 milliseconds for knee jerk
Central Delay = Reaction Time – Conduction Time
DEPT. OF PHYSIOLOGY, GMCM 52
52. • Minimum synaptic delay – 0.5 milliseconds
• So in knee jerk, 1 synapse could have been traversed
• Hence knee jerk is a monosynaptic reflex.
DEPT. OF PHYSIOLOGY, GMCM 53
53. Other examples of stretch reflex- deep tendon reflexes
1. Biceps jerk
2. Triceps jerk
3. Supinator Jerk
4. Ankle jerk
DEPT. OF PHYSIOLOGY, GMCM 54
55. Function of stretch reflex
1. Muscle spindle regulate the muscle length.
2. Stretch reflex helps to maintain muscle tone and
posture.
DEPT. OF PHYSIOLOGY, GMCM 56
56. Specific Learning Objectives
• Reflex
• Reflex Arc
• Classification of Reflex
• Stretch Reflex
• Inverse Stretch Reflex
• Reciprocal Innervation
• Withdrawal Reflex
• Properties of Reflexes
• Summary
DEPT. OF PHYSIOLOGY, GMCM 57
DEPT. OF PHYSIOLOGY, GMCM
57. Inverse Stretch Reflex
• Up to a point, the harder a muscle is stretched, the
stronger is the reflex contraction.
• However, when the tension becomes great enough,
contraction suddenly ceases and the muscle relaxes.
DEPT. OF PHYSIOLOGY, GMCM 58
58. This relaxation in response to strong stretch is called the
inverse stretch reflex or autogenic inhibition.
DEPT. OF PHYSIOLOGY, GMCM 59
59. • Stimulus – Strong stretch of the muscle
• Sense organ / receptor – Golgi Tendon Organ
• Afferent nerve – group Ib fibre
DEPT. OF PHYSIOLOGY, GMCM 60
60. • The Ib fibers enter the spinal cord through dorsal root ,
synapse with an inhibitory interneuron.
• It in turn terminate directly on the motor neuron
supplying the same muscle and causes relaxation of
the muscle.
DEPT. OF PHYSIOLOGY, GMCM 61
63. Inverse stretch reflex - protective reflex to prevent
tearing of the muscle or avulsion of the tendon from its
attachments to bone.
DEPT. OF PHYSIOLOGY, GMCM 64
64. Specific Learning Objectives
• Reflex
• Reflex Arc
• Classification of Reflex
• Stretch Reflex
• Inverse Stretch Reflex
• Reciprocal Innervation
• Withdrawal Reflex
• Properties of Reflexes
• Summary
DEPT. OF PHYSIOLOGY, GMCM 65
DEPT. OF PHYSIOLOGY, GMCM
65. • When we stretch the protagonist muscle, it will contract
through the stretch reflex pathway.
• The afferent neuron give a collateral which synapse
with an inhibitory interneuron.
Reciprocal Innervation
DEPT. OF PHYSIOLOGY, GMCM 66
66. That in turn inhibit the motor neuron supplying the
antagonist muscle producing relaxation of antagonist
muscle.
DEPT. OF PHYSIOLOGY, GMCM 67
69. DEPT. OF PHYSIOLOGY, GMCM 70
Specific Learning Objectives
• Reflex
• Reflex Arc
• Classification of Reflex
• Stretch Reflex
• Inverse Stretch Reflex
• Reciprocal Innervation
• Withdrawal Reflex
• Properties of Reflexes
• Summary
DEPT. OF PHYSIOLOGY, GMCM
70. Withdrawal Reflex
• Typical polysynaptic reflex
• Also called as nociceptive reflex.
• In response to a noxious stimulation of the skin or
subcutaneous tissues and muscle. e.g. pinprick, heat
DEPT. OF PHYSIOLOGY, GMCM 71
72. • Receptors – Nociceptors, free nerve endings of Aδ & C
fibers
• Response –flexor muscle contraction and inhibition of
extensor muscle.
• Helps the stimulated body part to be flexed and
withdrawn from the stimulus.
DEPT. OF PHYSIOLOGY, GMCM 73
73. Mild stimulus
• Flexor muscle contraction and inhibition of extensor
muscles.
• Part stimulated is flexed and withdrawn from the
stimulus.
• Flexor reflex
DEPT. OF PHYSIOLOGY, GMCM 74
75. Strong stimulus
• Not only flexion and withdrawal of that limb but also
extension of the opposite limb.
• This is called crossed extensor response.
• This is due to irradiation of stimulus and recruitment
of motor units.
DEPT. OF PHYSIOLOGY, GMCM 76
77. Many interneurons are involved in the circuit between
the incoming sensory neuron and the motor neurons of
the opposite side of the cord - responsible for the
crossed extension.
DEPT. OF PHYSIOLOGY, GMCM 78
78. Survival value of withdrawal reflex is difficult to demonstrate
in normal animals , but can be easily demonstrated in spinal
animal. (Sherrington)
DEPT. OF PHYSIOLOGY, GMCM 79
79. When the hind limb of a spinal cat is pinched
• the stimulated limb is withdrawn
• the opposite hind limb extends
• the ipsilateral forelimb is extended and
• the contralateral forelimb is flexed.
Called as Shifting Reaction.
DEPT. OF PHYSIOLOGY, GMCM 80
80. • This puts the animal in a position to run away from the
offending stimulus.
• This occurs because of irradiation of stimulus and
recruitment of motor units.
DEPT. OF PHYSIOLOGY, GMCM 81
81. Special features of withdrawal response
1. Withdrawal reflex is a protective reflex
Flexion of the stimulated limb gets it away from the
source of irritation, and extension of the other limb
supports the body.
DEPT. OF PHYSIOLOGY, GMCM 82
82. 2. After Discharge
After the painful stimulus is removed, the crossed
extensor reflex has an even longer period of after
discharge than does the flexor reflex.
DEPT. OF PHYSIOLOGY, GMCM 83
84. a. Because of the synaptic delay at each synapse, activity in
the branches with fewer synapses reaches the motor
neurons first, followed by activity in the longer pathways
Prolonged bombardment of the motor neurons from a
single stimulus - prolonged responses.
DEPT. OF PHYSIOLOGY, GMCM 85
85. b. Some of the branch pathways turn back on themselves,
permitting activity to reverberate.
Such reverberating circuits are common in the brain
and spinal cord.
DEPT. OF PHYSIOLOGY, GMCM 86
86. 3. Withdrawal reflex is prepotent
• They block the spinal pathways from any other reflex
activity taking place at the moment.
• This reflex gets priority when we consider other
reflexes occurring at that time
DEPT. OF PHYSIOLOGY, GMCM 87
87. 4. Local sign
• Dependence of the exact response on the location
of the stimulus.
• If the medial surface of the limb is stimulated, the
response includes some abduction, whereas stimulation
of the lateral surface will produce some adduction with
flexion.
DEPT. OF PHYSIOLOGY, GMCM 88
88. DEPT. OF PHYSIOLOGY, GMCM 89
Specific Learning Objectives
• Reflex
• Reflex Arc
• Classification of Reflex
• Stretch Reflex
• Inverse Stretch Reflex
• Reciprocal Innervation
• Withdrawal Reflex
• Properties of Reflexes
• Summary
DEPT. OF PHYSIOLOGY, GMCM
89. 1. Adequate Stimulus
• The quality of the stimulus that triggers a reflex is
generally very precise and is called the adequate
stimulus for the particular reflex.
• e.g. stretch of the muscle is the adequate stimulus for
stretch reflex.
DEPT. OF PHYSIOLOGY, GMCM 90
90. 2. Final Common Pathway
• The motor neurons that supply the extrafusal
fibers in skeletal muscles are the efferent side of
many reflex arcs.
• All neural influences affecting muscular contraction
ultimately funnel through them to the muscles.
DEPT. OF PHYSIOLOGY, GMCM 91
91. 3. One way conduction
DEPT. OF PHYSIOLOGY, GMCM 92
92. 4. Convergence
• Many to one projection.
• Termination of several neurons on one target neuron.
• e.g. many group Ia afferent fibers from muscle spindle
converging on a single α motor neuron.
DEPT. OF PHYSIOLOGY, GMCM 93
95. Divergence
• One to many projection
• Single presynaptic neuron divide into many branches.
• e.g. termination of pain fibers in withdrawal response on
many motor neurons via different sets of interneurons in
the spinal cord.
DEPT. OF PHYSIOLOGY, GMCM 96
97. 4. Occlusion
Response to simultaneous stimulation of two
presynaptic neurons < sum total of response obtained
when they are stimulated separately.
DEPT. OF PHYSIOLOGY, GMCM 98
98. Decrease in response since pre synaptic fibers overlap and
share post synaptic neurons.
DEPT. OF PHYSIOLOGY, GMCM 99
100. Neurons are in the subliminal fringe if they are not
discharged by an afferent volley, but have their
excitability increased.
DEPT. OF PHYSIOLOGY, GMCM 101
104. 8. Habituation
• Progressive decrease of the amplitude or frequency of
a motor response to repeated sensory stimulation.
• Not caused by sensory receptor adaptation or motor
fatigue.
DEPT. OF PHYSIOLOGY, GMCM 105
105. 9. Sensitization
Increased response of the target neuron to an afferent
stimulation, when the previously habituated stimulus is
paired with a noxious stimuli.
DEPT. OF PHYSIOLOGY, GMCM 106
106. Properties of Reflex
1. Adequate stimulus
2. Final common pathway
3. One way conduction
4. Reaction time
5. Summation
DEPT. OF PHYSIOLOGY, GMCM 107