The nerve impulse is an electrical signal transmitted by neurons in the nervous system. It occurs when voltage-gated sodium channels in the neuron's membrane open, allowing sodium ions to flow into the neuron and depolarize it. This then causes voltage-gated potassium channels to open, allowing potassium ions to flow out and repolarize the neuron, restoring the resting potential. The nerve impulse travels rapidly along the axon via this process of local depolarization and repolarization. At synapses, neurotransmitters are released by the presynaptic neuron, which can either excite or inhibit the postsynaptic neuron, determining whether or not an impulse continues along the nerve circuit.
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
these slides contain a brief introduction of neurons and its classification as well as details of generation of action potential, resting potential and eletrotonic potential.
Diffusion potential. Large Nerve. Na -K ATPase. Guyton and Hall. Medical Physiology. Dr. Nusrat Tariq. Professor Of Physiology. M.I.M.D.C. GOLDMAN HODGKIN KATZ EQUATION
this presentation explains what is action potential, how it is initiated.
it deals with short notes and brief description on the various processes that undergoes in the action potential
this presentation will help you out to summarize and conclude important points.
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
these slides contain a brief introduction of neurons and its classification as well as details of generation of action potential, resting potential and eletrotonic potential.
Diffusion potential. Large Nerve. Na -K ATPase. Guyton and Hall. Medical Physiology. Dr. Nusrat Tariq. Professor Of Physiology. M.I.M.D.C. GOLDMAN HODGKIN KATZ EQUATION
this presentation explains what is action potential, how it is initiated.
it deals with short notes and brief description on the various processes that undergoes in the action potential
this presentation will help you out to summarize and conclude important points.
Los Retos de Bogotá Entorno a la Bicicleta. jdacerom
Una relación de acciones, programas, proyectos, planes que en Bogotá se desarrollan entorno a la bicicleta, y como hacer para que eso se constituya en una política pública para los próximos años.
February JUGL on Software Quality Analysiscyrilpicat
Slides of February 2011 Java User Group in Lausanne dedicated to Software Quality Analysis
Videos soon available on Parleys: http://parleys.com/#id=102931&st=4
The nervous system is a complex collection of nerves and specialized cells known as neurons that transmit signals between different parts of the body. The presentation provides a simplified overview of the nervous system and its functions
My first attempt at this presentation for the IB Diploma Programme Biology course: topic 6.5 neurons and synapses. I'm hoping another great educator out there can take this, make it look a lot better, and then share it :)
Thanks to Steven Taylor and Chris Paine for all of their work and inspiration.
Please download and modify as you wish.
final note: I actually made this in google slides - I just checked the presentation and none of the links to the videos I used are there. Here is a link to the google slide presentation so you can find the videos: https://docs.google.com/a/igbis.edu.my/presentation/d/1eabpxEtwlDGt7EPRqQ_GPwxUBerszZQquWAhjRnU_WE/edit?usp=sharing
These slides contain the basic information and principle of nervous transduction, It also includes the information about the type of the neurons, structure of the neuron, resting and active membrane potential, synapes and events occurring in it, and introduction to the neurotransmitters.
Respiratory stimulants: types, complete discussion on indications, contraindications, assessment, patient notes and examples of stimulants both central and respiratory
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Complete pharmacology of Non steroidal Anti inflammatory Drugs, classification, Mechanism of action, Pharmacological actions, Indications, Contraindications, Adverse effects
Pharmacology laboratory experiment, both invivo and invitro includes interpolation, matching , bracketing, three point, four point bioassays with a note on hypoglycemic activity, acute skin irritation, acute eye irritaiton, pyrogen test, gastrointestinal motility test, physiological salt solutions
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
hematic appreciation test is a psychological assessment tool used to measure an individual's appreciation and understanding of specific themes or topics. This test helps to evaluate an individual's ability to connect different ideas and concepts within a given theme, as well as their overall comprehension and interpretation skills. The results of the test can provide valuable insights into an individual's cognitive abilities, creativity, and critical thinking skills
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
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Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
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Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
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Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
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Exposé invité Journées Nationales du GDR GPL 2024
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
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This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
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In this book, we use conservation of energy techniques on a fluid element to derive the Modified Bernoulli equation of flow with viscous or friction effects. We derive the general equation of flow/ velocity and then from this we derive the Pouiselle flow equation, the transition flow equation and the turbulent flow equation. In the situations where there are no viscous effects , the equation reduces to the Bernoulli equation. From experimental results, we are able to include other terms in the Bernoulli equation. We also look at cases where pressure gradients exist. We use the Modified Bernoulli equation to derive equations of flow rate for pipes of different cross sectional areas connected together. We also extend our techniques of energy conservation to a sphere falling in a viscous medium under the effect of gravity. We demonstrate Stokes equation of terminal velocity and turbulent flow equation. We look at a way of calculating the time taken for a body to fall in a viscous medium. We also look at the general equation of terminal velocity.
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Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
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https://www.etran.rs/2024/en/home-english/
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With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
2. The nerve impulse
This is the electrical signal which is
transmitted by the neurones around the
nervous system.
See Interactive Tutorial for Activity 8.2
3. Tissue fluid outside neurone [Na+
] high [K+
] low
Neurone cell membrane ______________________________
Cytoplasm inside neurone [Na+
] low[K+
] high
+ proteins-
+ ve
- ve
Distribution of ions and charge across the surface of a neurone.
The difference in charge results in a resting potential of –70 mV across
the membrane.
4. The resting potential is the result of:
•the action of an active
transport system called the
‘sodium pump’:
•i.e. involves a transporter
protein
+ the use of energy from
respiration
this ‘pumps
3 Na+ ions out and
2 K+ ions in
5. •Also the differential permeability of the neurone
membrane to Na+ and K+ ions
these ions can only cross the membrane via specific ion
channel proteins that allow facilitated diffusion:
(there are also so special ‘gated ions channels which
only allow ions to diffuse through them when they are
‘opened’ but they are not relevant here.)
ion channel protein
sodium pump
6. • The membrane is very impermeable to Na+ ions so
these cannot diffuse back in.
• The membrane is slightly more permeable to K+ ions
so these diffuse out slowly (down their concentration
gradient).
• This establishes electrochemical diffusion gradients
for the ions across the membrane.
• The net result is that relatively more +ve ions end
up outside the neurone than remain inside to balance
the – ve charged proteins
• so the outside is more positive with respect to the
inside;
• this charge difference is responsible for the resting
potential.
• At this point the neurone is said to be polarised.
7. When a nerve impulse is transmitted along a neurone a wave of
electrical activity passes along it
(NB: it is NOT a flow of electrons so it is not an electrical
current)
This can be detected (e.g. by
using a cathode ray oscilloscope
with electrodes placed inside and
outside the neurone) as a
transient change in electrical
charge on the membrane
surface – this is called an
ACTION POTENTIAL and is the
basis of the nerve impulse.
The nerve impulse.
11. The action potential
[1] Resting potential: Na+ and K+ special ‘voltage gated’
ion channels closed: neurone is polarised.
[2] Na+ gated channel proteins open (due to a change
in shape of the protein itself: makes the membrane
more permeable to Na+ ions now) which allows Na+
ions to diffuse into the neurone down the
electrochemical diffusion gradient.
[3] This causes the inside of the neurone to become
increasingly more + ve: this is depolarisation and
neurone has become depolarised
12. [4] Na+ channels close and K+ gated channels now
open
[5] K+ ions diffuse out of the neurone down the
electrochemical diffusion gradient, so making the
inside of the neurone less positive (= more negative)
again: this is repolarisation and the neurone has
become repolarised
[6] The neurone has its resting potential restored.
During this time the Na+ and K+ ions which have
diffused in/out of the cell are redistributed by
active transport (sodium pump)
[NB: the ion movements during the action potential
occur by facilitated diffusion; active transport is not
involved]
16. Properties of the action
potential.
Action potentials
• have a threshold:
• this is the minimum level of stimulus necessary to
cause depolarisation (i.e. open the ion channels)
• are all or nothing:
• all action potentials are the same size, irrespective of
the intensity of the stimulus
• consequently information about the intensity of a
stimulus is coded in the number of impulses - strong
stimulus many action potentials etc
17. • have a refractory period (about 1 ms);
• the ion channels remain closed and cannot be
made to reopen so no further depolarisation is
possible; the consequences are
• it separates impulses from one another by a
fraction of a msec, and so imposes a maximum
on the number of impulses which can be
transmitted along a neurone in a given time
• it ensures impulses can only pass in one
direction along an axon, i.e. forward into the
next resting region but not back into a region
still in its refractory period.
18. Role of action potentials in the
transmission of a nerve impulse.
• A STMULUS causes the Na+ gated
channel proteins to open (effectively
causes a change in shape of the protein
itself)
• which allows Na+ ions to diffuse down the
concentration gradient across the
membrane into the cell and so set off an
action potential.
• [see handout]
19.
20.
21. Sodium gates open
Sodium ions flow
into neurone
How action potentials are transmitted along a neurone
22. Sodium gates close
Potassium gates open
Potassium ions flow
out of neurone
Sodium gates in next bit of membrane open and sodium ions flow in
Sodium pump redistributes
sodium and potassium ions
after impulse has passed
23. Speed of conduction of nerve
impulses.
• Transmission speeds can range from 0.5
m per sec to over 100 m per sec.
• Impulse transmission can be speeded up
by:
25. Myelin sheath
Bundle of nerve fibres
Connective tissue coat of nerve
TS Nerve
but this imposes constraints on packing a large number of large axons into a nerve
26. •having a myelin sheath;
the myelin sheath is
composed of tightly
packed layers of the cell
membrane of the
Schwann cells which are
wrapped around the axon
27.
28. • this is rich in lipid (called myelin) which
makes the axon impermeable to ions so
they are unable to diffuse between the
tissue fluid and the neurone
• so action potentials cannot be generated
by the myelinated regions (it acts as an
insulator);
29. • action potentials can only be generated
at the nodes of Ranvier
• so the local currents involved in nerve
impulse transmission flow over longer
distances:
• thus action potential seem to ‘jump’
from node to node (this is called
salutatory conduction):
32. • since the intervening parts of the axon
membrane do not have to be successively
depolarised it takes
• less time for the action potentials to pass
from node to node
• this results in nerve impulse transmission that
is much faster,
• the consequence of which is that smaller
myelinated nerves can transmit impulses much
faster than larger non-myelinated ones
• which alleviates the ‘packing problem’.
33. • temperature
• which affects the rate of diffusion and
the rate of energy release by
respiration for active transport (since it
is controlled by enzymes)
• the consequence is that nerve impulse
transmission is faster in endothermic
animals which maintain a high body
temperature.
42. N.B. this is not a
physical junction,
there is actually a
small gap of approx 20
nm between the cells
so there is no
membrane continuity so
nerve impulses cannot
cross directly.
synaptic vesicles
synaptic bulb
pre-synaptic membrane
post-synaptic membrane
43.
44. • Instead transmission is by chemicals
called neurotransmitters
• These made in the Golgi body (synthesis
requires energy from respiration)
• stored in vesicles in the synaptic bulb
45. • There are several different types of
neurotransmitters, of which two are
• Acetyl choline
• (used in the voluntary [motor neurones
muscles] and parasympathetic nervous
systems)
• Noradrenaline
• (used in the sympathetic nervous system)
46. How nerve impulses are transmitted across a synapse by neurotransmitters
51. neurotransmitter molecules
diffuse across the synaptic
cleft neurotransmitter receptors are
membrane protein with binding sites with
a shape complementary to the
neurotransmitter
neurotransmitters broken
down by enzymes so the
ion channels to close and
the receptors are available
again and so the resting
potential can be re-
established
this sequence takes 0.5 msec which results in a synaptic delay in the
transmission of impulses.
52.
53. Types of synapse.
Excitory synapses
• Binding of neurotransmitter to postsynaptic
neurone
• opens Na+ gated channels
Na+ diffuses IN
depolarisation
action potentials
• so nerve impulses can continue around the
nerve circuit.
54. Inhibitory synapses
• Binding of neurotransmitter to postsynaptic
neurone opens K+ gated channels
• K+ diffuses OUT
inside of neurone becomes even more – ve
and so impossible to depolarise
no action potentials
• so nerve impulses cannot continue around the
nerve circuit.
55. Functions of synapses.
Enables impulses to be transmitted from
one neurone to another, so enables nerve
circuits to function.
• Neurotransmitter only released from the
• presynaptic neurone,
• so nerve impulses can only be transmitted
• IN ONE DIRECTION around a nerve
circuit
56. • Sometimes neurotransmitter released by a
single neurone is insufficient to depolarise the
postsynaptic neurone;
• however simultaneous release of
neurotransmitter from the synapses several
neurones
• (sometimes from other nerve circuits – known as
integration)
• will be sufficient to cause sufficient
depolarisation to generate nerve impulses
• this is called SUMMATION.
59. Summative effect of
excitory and inhibitory
synapses also determines
whether nerve impulses will
be generated in the
postsynaptic neurone.
60. • Nerve impulses are only transmitted if
threshold of postsynaptic neurone is
exceeded,
• so ensures only significant information is
passed around the circuit
• (so insignificant, low level stimuli get
“filtered out”).
61.
62. animations of how drugs work
• http://www.pbs.org/wnet/closetohome/science/
• http://learn.genetics.utah.edu/units/addiction/d