This document summarizes key concepts about synapses and synaptic transmission. It defines a synapse as the junction point between neurons. It classifies synapses based on their structure and function. It describes the anatomical components of a synapse including the presynaptic terminal, synaptic cleft, and postsynaptic membrane. It explains the events that occur during synaptic transmission including the release of neurotransmitters from the presynaptic terminal and their effects on the postsynaptic membrane. It also discusses properties of synapses such as synaptic delay, summation, inhibition, and plasticity which are important for neural communication and functions like learning and memory.
this ppt shares what synapses are and how information of one neuron is transmitted to other through the synapses. it also includes the properties and plasticity of synaptic transmission
Synaptic transmission types I Steps of chemical neurotransmission I Nervous S...HM Learnings
Synaptic transmission - types I Steps of chemical neurotransmission I Nervous System Physiology
This video will be about the following things:
1. Synatic transmission- Definition
2. Types of synaptic transmission
3. Process of electrical neurotransmission
4. Process of chemical neurotransmission
5. Difference between electrical and chemical neurotransmission
6. Steps of chemical neurotransmission
7. Synthesis of neurotransmitters and neuropeptides
8. Storage of neurotransmitters and neuropeptides
9. Synaptic vesicle proteins
10. Release of neurotransmitters
11. SNARE complex formation
12. Recycling of synaptic vesicle (exo-endocytic cycle)
13.Binding of neurotransmitters to postsynaptic receptors
14. Termination of action of released neurotransmitter
You can also watch the same topic on HM Learnings Youtube channel.
You can also follow HM Learnings on facebook, instagram and twitter for daily updates
this ppt shares what synapses are and how information of one neuron is transmitted to other through the synapses. it also includes the properties and plasticity of synaptic transmission
Synaptic transmission types I Steps of chemical neurotransmission I Nervous S...HM Learnings
Synaptic transmission - types I Steps of chemical neurotransmission I Nervous System Physiology
This video will be about the following things:
1. Synatic transmission- Definition
2. Types of synaptic transmission
3. Process of electrical neurotransmission
4. Process of chemical neurotransmission
5. Difference between electrical and chemical neurotransmission
6. Steps of chemical neurotransmission
7. Synthesis of neurotransmitters and neuropeptides
8. Storage of neurotransmitters and neuropeptides
9. Synaptic vesicle proteins
10. Release of neurotransmitters
11. SNARE complex formation
12. Recycling of synaptic vesicle (exo-endocytic cycle)
13.Binding of neurotransmitters to postsynaptic receptors
14. Termination of action of released neurotransmitter
You can also watch the same topic on HM Learnings Youtube channel.
You can also follow HM Learnings on facebook, instagram and twitter for daily updates
Nervous system forms an interconnecting fibers of communication network.
In the ‘hard-wiring’ of the nerves, the signals travel in the form of a flow of electrical current called nerve impulses.
The stimulus-response reactions afford internal constancy in the face of environmental changes.
this ppt explains the concept of the gap junction, inotropic, and metabotropic.
the difference between the temporal summation and the spatial summation.
explanation of the function of the neurotransmitter.
difference between the inhibitory and excitatory postsynaptic potential.
Nervous system forms an interconnecting fibers of communication network.
In the ‘hard-wiring’ of the nerves, the signals travel in the form of a flow of electrical current called nerve impulses.
The stimulus-response reactions afford internal constancy in the face of environmental changes.
this ppt explains the concept of the gap junction, inotropic, and metabotropic.
the difference between the temporal summation and the spatial summation.
explanation of the function of the neurotransmitter.
difference between the inhibitory and excitatory postsynaptic potential.
Nerve Impulse is defined as a wave of electrical chemical changes across the neuron that helps in the generation of the action potential in response to the stimulus. This transmission of a nerve impulse across the neuron membrane as a result of a change in membrane potential is known as Nerve impulse conduction.
Mechanism of Nerve Impulse Conduction
Nerve impulse conduction is a major process occurring in the body responsible for organized functions of the body. So, for conduction of nerve impulse there are two mechanisms:
Continuous conduction
Saltatory conduction
Classification and structure of synapsesAlaaAlchyad
Synapses can be classified by the type of cellular structures serving as the pre- and post-synaptic components. ... The axon can synapse onto a dendrite, onto a cell body, or onto another axon or axon terminal, as well as into the bloodstream or diffusely into the adjacent nervous tissue.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Biological screening of herbal drugs: Introduction and Need for
Phyto-Pharmacological Screening, New Strategies for evaluating
Natural Products, In vitro evaluation techniques for Antioxidants, Antimicrobial and Anticancer drugs. In vivo evaluation techniques
for Anti-inflammatory, Antiulcer, Anticancer, Wound healing, Antidiabetic, Hepatoprotective, Cardio protective, Diuretics and
Antifertility, Toxicity studies as per OECD guidelines
Macroeconomics- Movie Location
This will be used as part of your Personal Professional Portfolio once graded.
Objective:
Prepare a presentation or a paper using research, basic comparative analysis, data organization and application of economic information. You will make an informed assessment of an economic climate outside of the United States to accomplish an entertainment industry objective.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
2. Objectives
1.Define synapse
2. Discuss the classification of synapses
3.Describe the functional anatomy of synapse
4.Describe the events occurring at the synapse
5.Discuss the properties of synapse
Reference:
Guyton and Hall-TB of Medical Physiology 13th edition: page 543-55
3. Defn:
A junction point where axon or other part of nerve
cell (presynaptic cell) terminates on the dendrites or
other part of another neuron (postsynaptic cell).
8. Type I (Gray’s I
synapses)
Type II (Gray’s II
synapses)
Structure Asymmetric symmetric
Synaptic space wide Narrow
Post synaptic
membrane
thickened thin
ECF in cleft present absent
NTs. NT:5HT,Glutamate,
NE,E,DOPA
NT GABA,Glycine
Action Excitatory Inhibitory
Type Axo-dendritic Axo-somatic
9. Structure of chemical synapse
1. Presynaptic
• A flat,
• 20-μm2 membrane area,
• Synaptic knob ,
• tuft, bulb of axon
2. Synaptic cleft
• (20-30 nm)
3. Postsynaptic neuron
• Grid
• Sub synaptic membrane,
• Sub synaptic web.
10.
11. Post synaptic receptors - 2 components
1. Binding site that face
the cleft to bind the NT
2. Ionophore: It passes through
the membrane to the interior.
12. Ion channels
Channels Cation channels Anion channels
Ions Na+ (most common) Cl¯ (mainly)
Other ions K+,Ca2
+
Action Opening of Na+ channels
increase membrane
potential in positive
direction toward
threshold level of
excitation (+) neuron.
Opening of Cl¯ channels
diffusion of negative charges
into the membrane decrease
membrane potential making
it more negative away
from threshold level (-)
neuron.
13. Second messenger system in the post-synaptic membrane.
Significance: when prolonged post-synaptic changes are
needed to stay for days,months,Years
Ex: memory storage.
14. Chemical (common) Electrical
NT NT liberated No NT
Synaptic Cleft 20-30 nm 2 nm
Delay 1-3 msec Absent
Sensitive hypoxia Sensitive Insensitive
Process Active Passive
Transmission Slower Fast
Direction of flow Unidirectional pre-post. Bi/Unidirectional
Inhibitory Effect Inhibitory +/- No
Post synaptic
duration
Longer-mediated by
second messengers.
No
Direction of Ions
current transmission
From outside to inside From cell inside to
inside.
18. 3:Reverberating
Defn: Impulse pass from presynaptic neuron & again back to
presynaptic neuron to cause continuous stimulation of
presynaptic neuron.
Significance:
Breathing, coordinated muscular activities,
waking up, & short term memory.
19. 4:Parallel after discharge circuits:
Defn: Involve a single presynaptic cell that stimulates a group of
neurons ,which then synapse with a common postsynaptic cell.
Significance :
Precise activities like calculations
20. Graded Potentials
• Amplitude varies with conditions of
initiating
• Can be summed up.
• No threshold, refractory period
• Duration varies with initiating conditions
• Can be depolarization/ hyperpolarization
• Mechanism depends on ligand-sensitive
channels or other chemical or physical
changes
• Initiated by environmental stimulus
(receptor)
• Affects only limited portion of cell
membrane.
21. 1:One way conduction
2:Synaptic delay
3:Post Synaptic Potential:
A: EPSP
I: Spatial and
II: Temporal summation
B: IPSP:
I :Presynaptic inhibition
II :Postsynaptic inhibition
III :Reciprocal inhibition
Properties of synapses
22. 6: Conversions and divergence
7: Occlusion and subliminal fringe phenomenon
8: Facilitation
9: Synaptic fatigue
10: Recruitment
11: Synaptic plasticity ,learning and habituation
12: Reverberation
13: Reciprocal inhibition
14: After discharge
15: Effect of Acidosis & alkalosis,Hypoxia,Drugs..
23. One way conduction
Bell Magendie law:
Forward /Orthodromic conduction.
Synapses allow only one way conduction from pre to post
synaptic neuron.
Antidromic /backward conduction
IF spread back over soma or dendrites.
It produce no effect.
Significance: for orderly conduction of impulses in one
direction only.
24. Synaptic delay
Defn: Time between arrival of an AP to the synaptic knob & the
occurrence of response in the postsynaptic neuron.
Generation of Post Synaptic Potential & its summation to generate
AP.
Mechanism: Release and diffusion of the NTs.
Binding of the NTs. to the post Synaptic membrane.
Minimum delay : 0.5 msec.
Significance: can be used to determine the number of synapses
present in a polysynaptic reflex.
25. EPSP IPSP
Cause by binding of the
excitatory NT & makes
post SM generate an AP.
by the inhibitory NT &
makes Post SM membrane
less likely to generate an AP
Ions
Flow
+vly ions. –vly ions.
Leads to Depolarization.
Brings the Post SM
towards threshold.
Hyperpolarization.
Takes the post SM away
from threshold.
Effect
on Post
SM
Excited.
Facilitated the firing of
an AP on Post SM.
Less excited.
Lowers the firing of an AP
on the post SM.
NTs &
ions
involved
Glutamate or Na+
aspartate ions
Glycine and GABA Cl-.
26. Temporal (Time):
When repeated stimuli applied in short duration.
Spatial (Space):
When post synaptic membrane receives impulses
simultaneously from large number of presynaptic terminals.
27. Inhibition
Postsynaptic : Direct by releasing inhibitory NT due to refractory
period. By development of IPSP .
Golgi-tendon inhibition
Presynaptic: Release of GABA opens K+ or Cl channels—leads to
diffusion of K ions or Cl ions .
Hyperpolarization of post synaptic membrane by inhibitory.
28. Location: In spinal alpha motor neuron
Neuron inhibit those neuron which excite it
Significance:
It serves to limit excitability of motor neurons.
Feedback (Renshaw cell inhibition)
29. Neuron connected through 2 pathways Excitatory and inhibitory.
It allows brief and precisely timed excitation.
EX : Deep neural circuit of cerebellum
Significance :
For restriction over neurons and muscles to react properly
and appropriately
Feed forward inhibition.
30. Fatigue
Defn:
Progressive decline in rate of discharge of the Post SN,
Following intense prolonged stimulation of the PreSN .
If sever can lead to compete stop called synaptic block
Temporary in nature.
Cause:
Fatigue is mainly due to exhaustion of Nm substances .
Due to lack of time to resynthesize and reuptake of NT.
Significance:
Protects CNS from over excitability.
31. Dale law
Defn:
Only one type of NT is released at one synapse.
Either excitatory or Inhibitory.
Occlusion
Defn:
Response to stimulation of 2 presynaptic neurons is
less than sum total of the response obtained when
stimulated separately.
32. Synaptic plasticity , and learning
Defn:
Synaptic transmission can be increased or decreased
on the basis of past experience
Defn:
When presynaptic axon is stimulated with several
consecutive individual stimuli each evokes larger post synaptic
potential than previous stimuli
Post tetanic potentiation:
33. Synaptic plasticity , and learning
Also called post tetanic facilitation or potentiation.
Mechanism:
By excess rise of Ca ions in the synaptic knob which
causes more vesicle to release NT ,producing a greater
response of the Post SN.
Significance: Not known. May be short term memory
34. Long term potentiation
Similar to post tetanic potentiation.
Last for several days.
Mechanism:
It is initiated by an increase of intracellular calcium
ion in post SN through opening of Ca 2+ channels in post
SM after binding of glutamate to its specific NMDA
receptors
35. Significance:
Seen in many parts of CNS
Mainly in hippocampus
Play role in long term memory and learning.
Editor's Notes
Channels:
Connexon
Diameter is 2nm
6 subunits:
connexin
Axodendritic Axosomatic
Marked thickening slight thickening which is not continous
Wider 30nm 20nm
Filled with dense extrcellular tissue no such tissue is present
Sites CC , C LIMBING FIBRES A.N.S, BASKET CELLS
1. SPHERICAL-E
Small-molecule NT (synthesized
in the cytoplasm of the terminal
buttons and packed into vesicles
by the Golgi complex)
2. HORIZONTAL/FLAT-I
(synthesized in the soma by
ribosomes and packed into vesicles
by the soma’s Golgi complex
and then moved down to the
terminals by microtubules)
Clear vesicles acetylcholine) Dense-core vesicles(catecholamine)
Small-molecule transmitters (synthesized in the cytoplasm of the terminal buttons and packed into vessicles by the Golgi complex)
Large-molecule (peptide) transmitters (synthesized in the soma by ribosomes and packed into vessicles by the soma’s Golgi complex and then moved down to the terminals by microtubules)
A chemical synapse consists
Chemical synapses between neurons are generally small, often less than 1 μm in diameter, which means that their detailed structure can be seen only with an electron microscope;
light microscope, brain synapses are usually visible only as swellings along or at the termination of the axons . .
Synapses are polarized, which means that their two apposed sides have different structures. This polarity reflects the fact that most synapses transmit information in one direction but not in the other (we will see that some rare exceptions do exist). The presynaptic side contains numerous clear vesicles, 40 to 50 nm in diameter, that appear empty when viewed by transmission electron microscopy. Synaptic termini may also contain large (100 to 200 nm in diameter), dense-core secretory granules that are morphologically quite similar to the secretory granules of endocrine cells. These granules contain neuropeptides, that is, peptides or small proteins that act as neurotransmitters and for which receptors exist in the postsynaptic membranes
. Endocrine hormones such as adrenocorticotropic hormone, vasoactive intestinal polypeptide, and cholecystokinin are found in dense-core secretory granules present in the terminals of certain central and peripheral neurons.
The clear synaptic vesicles (i.e., not the dense-core granules) are anchored and shifted about by a dense network of cytoskeletal proteins. Some vesicles are clustered close to the part of the presynaptic membrane that apposes the synaptic contact; these vesicle attachment sites are called active zones. Synaptic vesicles are lined up several deep along the active zones, which are probably the regions of actual exocytosis. The number of active zones per synapse varies greatly (active zones
. Most synapses in the central nervous system (CNS) have relatively few active zones, often only 1 but occasionally as many as 10 or 20 (versus the hundreds in the neuromuscular junction). If we could view the presynaptic face of an active zone from the perspective of a synaptic vesicle, we would see filaments and particles projecting from the presynaptic membrane, often forming a regular hexagonal arrangement called a presynaptic grid. Specific points along the grid are thought to be the vesicle release sites.
Unlike the clear synaptic vesicles containing non-peptide transmitters, dense-core secretory granules are distributed randomly throughout the cytoplasm of the synaptic terminus. They are not concentrated at the presynaptic density, and they do not appear to release their contents at the active zone. Although the molecular pathways that control exocytosis of the neuronal dense-core granules are still being elucidated, it appears that a rise in [Ca2+]i is a primary stimulus.
An action potential consists of a temporary change in a neuron’s electrical potential
The neuron must recover to Resting Potential