Difference between revisions of "PhET/C3/Neuron/English"

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Point to ion '''channels'''.
 
Point to ion '''channels'''.
  
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|| The '''simulation''' window shows a cross-section of a axon.  
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|| The '''simulation''' window shows a cross-section of an axon.  
  
 
The nerve fibre or axon is like a cylinder.  
 
The nerve fibre or axon is like a cylinder.  
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|-  
 
|-  
 
|| Click the check-box for '''Potential Chart''' in '''Show''' box.  
 
|| Click the check-box for '''Potential Chart''' in '''Show''' box.  
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|| In the '''Show''' box, Check the check-box for '''Potential Chart'''.  
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|| In the '''Show''' box, check the check-box for '''Potential Chart'''.  
  
 
|-  
 
|-  
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|-  
 
|-  
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|| Click on the '''Play''' button.  
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|| Click on '''Play''' button.  
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|| Click on the '''Play''' button to start the '''simulation'''.  
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|| Click on '''Play''' button to start the '''simulation'''.  
  
 
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* Function of '''leak''' and '''gated channels'''
 
* Function of '''leak''' and '''gated channels'''
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|| '''Slide Number 12'''
  
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'''Summary'''
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 +
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* Membrane permeability  
 
* Membrane permeability  
  
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|-  
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'''Assignment'''  
 
'''Assignment'''  
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'''About Spoken Tutorial project'''  
 
'''About Spoken Tutorial project'''  
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'''Spoken Tutorial workshops'''  
 
'''Spoken Tutorial workshops'''  
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'''Forum for specific questions:'''  
 
'''Forum for specific questions:'''  
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'''Acknowledgements'''  
 
'''Acknowledgements'''  
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'''Acknowledgement'''  
 
'''Acknowledgement'''  

Latest revision as of 15:43, 16 November 2018


Visual Cue Narration
Slide Number 1

Title Slide

Welcome to this spoken tutorial on Neuron PhET simulation.
Slide Number 2

Learning Objectives

In this tutorial we will,

Demonstrate Neuron, PhET simulation.

Slide Number 3

System Requirement

Here I am using,

Ubuntu Linux OS version 14.04

Java version 1.7.0

Firefox Web Browser version 53.02.2

Slide Number 4

Pre-requisites

To follow this tutorial,

Learner should be familiar with topics in high school biology.

Slide Number 5

Learning Goals

Using this simulation we will learn about,
  • Movement of ions across the membranes when the neuron is stimulated or at rest
  • Function of leak and gated channels
Slide Number 6

Learning Goals

  • Membrane permeability
  • Sequence of events that generates an action potential
Slide Number 7

Link for PhET simulation

Use the given link to download the simulation.

http://phet.colorado.edu

Open Downloads folder and show. I have already downloaded Neuron simulation to my Downloads folder.
Click on Neuron_en.html file.

Right click on Open With Firefox Web Browser option.

Point to Neuron simulation.

To open the simulation, right click on Neuron_en.html file.

Select Open With Firefox Web Browser option.

Simulation opens in the browser.

Point to the simulation window.

Point to axon.

Point to axoplasm.

Point to axon membrane.

Point to ion channels.

The simulation window shows a cross-section of an axon.

The nerve fibre or axon is like a cylinder.

The interior of axon is filled with axoplasm.

Exterior is covered with a thin axon membrane.

Different types of ion channels are present on axon membrane.

Pointer on the zoom slider. On the top-left corner of the screen, we have a zoom slider.

This helps to see the close-up view of the membrane.

Point to Legend box and Show box. On the right-side of the interface, you will see a Legend box and Show box.

Legend box shows ions and channels.

Point to the all check-boxes. In the Show box, we have check boxes to show,

All Ions

Charges

Concentrations

Potential chart

Show all the buttons at the bottom of the window. At the bottom of the screen we have,
  • a box with Fast Forward, Normal and Slow Motion radio buttons
  • Rewind, Play/Pause and Step buttons
  • Stimulate Neuron button and
  • Reset button
Cursor on the neuron. In this simulation, we will see the movement of, sodium and potassium ions across the axon membrane.
Slide Number 8

About Neuron

About Neuron

Neurons are highly specialized cells in nervous system.

They can detect, receive and transmit different kinds of stimuli.

Drag slider to + ve side. Drag the zoom slider, to zoom-in the axon membrane.
Point to ion channels.

Point to Leak channel and gated channel.

The ion channels are selectively permeable to different ions.

Here, 2 different types of ion channels are shown.

Leak Channel and Gated Channel.

Point to Legend panel.

Point to sodium and potassium, leak and gated channels in the Legend panel.

For reference please refer to the Legend panel on the right-side of the screen.

There are sodium and potassium, Gated and Leak channels in the Legend panel.

Point to leak channels.

Point to gated channels.

Leak ion channels are always open.

They are responsible for the resting membrane potential.

Gated Channels open or close in response to a stimulus.

Click on Slow Motion radio button at the bottom of the screen.

Point to Sodium and potassium ions.

Point to the respective leak channels.

To observe the exchange of ions properly, keep the simulation speed slow.

Click on Slow Motion radio button at the bottom of the screen.

Sodium and potassium ions are seen continuously moving in and out of the membrane.

They move through the respective leak channels.

In the Show box, click on Charges and Concentrations check-boxes. In the Show box, check against Charges and Concentrations check-boxes.
Point to concentrations of Sodium and potassium ions outside and inside of the membrane. Note the concentrations of potassium and sodium ions, outside and inside the membrane.

Axoplasm will contain

  • high concentration of potassium ions
  • and low concentration of sodium ions
Point to concentrations outside Sodium and potassium ions. The fluid outside the axon contains
  • low concentration of potassium ions
  • and high concentration of sodium ions

This forms a concentration gradient across the membrane.

Point to charges on the membrane. As a result, outer surface of the membrane is positively charged.

While its inner surface becomes negatively charged.

Therefore the membrane is polarised.

Slide Number 9

Resting Potential

Resting Potential

The electrical potential difference across the axon membrane is called Resting Potential.

Click the check-box for Potential Chart in Show box. In the Show box, check the check-box for Potential Chart.
Click on Stimulate Neuron button To stimulate the neuron, click on Stimulate Neuron button.
Point to ions and channels.

Point to the charges.

Notice that Sodium ions move inside and potassium ions move outside.

During the exchange of ions charges get exchanged.

Cursor on the membrane.

Point to gated channel.

Notice the change in polarity across the axon membrane.

At this stage the nerve fibre is said to be in action potential or depolarized.

This movement of ions happen through gated channels.

Click on Pause button. Pause the simulation briefly.
Point to the peak in membrane potential chart. Observe the increase in the membrane potential in the potential chart.

Action potentials in neuron are known as nerve impulses.

Click on Play button. Click on Play button to start the simulation.
Cursor on the membrane.

Point to sodium and potassium ions.

After a period of action potential, again reversal of the process takes place.

During this process the sodium and potassium ions move in and out.

Cursor on the interface.

Click on Stimulate Neuron button.

This restores the resting potential of the membrane.

This process is called repolarization.

Now the fibre is ready to receive responsive stimulations.

Slide Number 10

Summary

Let us summarize,

In this tutorial we have demonstrated,

How to use, Neuron PhET simulation.

Slide Number 11

Summary

Using this simulation we have learnt about,
  • Movement of ions across the membranes when the neuron is stimulated or at rest
  • Function of leak and gated channels
Slide Number 12

Summary

  • Membrane permeability
  • Sequence of events that generates an action potential
Slide Number 13

Assignment

As an Assignment

Observe,

the difference between a gated channel and a leak channel.

the sequence in which ion channels open or close to propagate an action potential.

Slide Number 14

About Spoken Tutorial project

The video at the following link summarizes the Spoken Tutorial project.

Please download and watch it.

Slide Number 15

Spoken Tutorial workshops

The Spoken Tutorial Project team:

conducts workshops using spoken tutorials and gives certificates on passing online tests.

For more details, please write to us.

Slide Number 16

Forum for specific questions:

Do you have questions in THIS Spoken Tutorial?

  • Please visit this site
  • Choose the minute and second where you have the question.
  • Explain your question briefly
  • Someone from our team will answer them.
Please post your timed queries on this forum.
Slide Number 17

Acknowledgements

This project is partially funded by Pandit Madan Mohan Malaviya National Mission on Teachers and Teaching.
Slide number 18

Acknowledgement

The Spoken Tutorial Project is funded by NMEICT, MHRD Government of India.

More information on this Mission is available at this link.

This tutorial is contributed by Snehalatha Kaliappan and Meenal Ghoderao from IIT Bombay.

Thank you for joining.

Contributors and Content Editors

Meenalghoderao, Snehalathak

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