Hybridation of Atomic Orbitals

ELECTRON DELOCALIZATION AND RESONANCE: http://www.utdallas.edu/~scortes/ochem/OChem1_Lecture/Class_Materials/06_electr_delocal_res.pdf

Delocalized Electrons: http://chemed.chem.wisc.edu/chempaths/GenChem-Textbook/Delocalized-Electrons-1042.html

Hybridization: http://www.organicchem.org/oc1web/lecture/HYBRIDIZATION.pdf

Hybridization of Carbon: http://pages.towson.edu/ladon/carbon.html

sp3 = 4 hybridized orbitals

sp2 = 3 hybridize orbitals + 1 unhybridized p orbital

sp = 2 hybridized orbitals + 2 unhybridized p orbitals

sp3: Carbon in Methane contains 4 valence electrons each shared with H atoms. So all the orbitals are mixed.

C2H4: 

sp2: Carbon contains 4 Valence Electons but it is only sharing 3 of them, so 1 p orbital is unmixed

C2H2: 

sp: Carbon has 4 valence electrons but shares only 2 of them, so 2 p orbitals are unmixed

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Resume/CV Building

Resume Action Words: http://careercenter.umich.edu/article/resume-action-words

Notes on preparing a resume: http://web.jhu.edu/prepro/Forms/Resumes_premed.pdf

Good Resume Examples for various positions: http://careercenter.wustl.edu/tools/careerdevelopment/Documents/ResumeCoverLetterWriting.pdfhttp://workalpha.com/resume-samples/medical-school-admission-resume/,

Resume and Coverletter Examples from Harvard: http://www.ocs.fas.harvard.edu/students/extension-careers/guides/ResumeCoverLetter.pdf

How to Write a Resume for Med School: http://www.varsitytutors.com/blog/med+school+resume

Tips fro Pre-med Students on Resume Building: http://www.aboutthemcat.com/medical-school/resume-building.php

6 Tips to a good CV: http://blog.accepted.com/2012/06/20/the-six-commandments-for-a-successful-cv/

CV Standard Format: http://medschool.umaryland.edu/academicadmin/cv_format.asp

 

 

Incorporating Active Learning to Studying

Active learning not only helps you engage with the study material but it also helps you recall the information much more efficiently into long term memory than passive learning.

Active Learning Strategies to Remember:

  1. Write summaries in your own words of text  or notes
  2. Write questions to summarize notes or text
  3. Take up note cards to summarize notes
  4. Develop a chart to organize material
  5. Construct possible quiz and exam questions
  6. Teach the material to someone
  7. Recite notes out loud
  8. Write in the margins of the text
  9. Prepare summary questions
  10. Quiz yourself from prepared questions periodically instead of rereading notes before exam
  11. Recite out loud a sentence using term in context instead of memorizing definitions
  12. Annotate in margins to summarize main ideas instead of rereading text before the exam
  13. Annotate from text and write questions to summarize notes instead of recopying notes
  14. Prepare outline from text and talk to instructor instead of reading someone else’s notes

Source: http://luc.edu/advising/pdfs/A_Guide_to_Active_Learning.pdf

 

Cornell Note-Taking Method

Introduction: The Cornell method provides a systematic format for condensing and organizing notes without laborious recopying. After writing the notes in the main space, use the left-hand space to label each idea and detail with a key word or “cue.” Very similar to SQ3R, but is done using notetaking. Source: http://www.studygs.net/texred2.htm

Method- Rule your paper with a 2 ½ inch margin on the left leaving a six-inch area on the right in which to make notes. During class, take down information in the six-inch area. When the instructor moves to a new point, skip a few lines. After class, complete phrases and sentences as much as possible.

For every significant bit of information, write a cue in the left margin. To review, cover your notes with a card, leaving the cues exposed. Say the cue out loud, and then say as much as you can of the material underneath the card. When you have said as much as you can, move the card and see if what you said matches what is written. If you can say it, you know it.

Advantages

Organized and systematic for recording and reviewing notes. Easy format for pulling out major concept and ideas. Simple and efficient. Saves time and effort. “Do-it-right-in-the-first-place” system.

Why use the Cornell Method?

  • To greatly minimize your “rate of forgetting”
  • Don’t take notes = Forget 60% in 14 Days
  • Take some notes = Remember 60%
  • Take organized notes and do something with them = Remember 90 – 100% indefinitely

Source: https://docs.google.com/document/d/1hoQ6GTdfumFZBDZ_oXXE-Wz0XjDPBMU-1vXUbrNLyWA/edithttp://lsc.cornell.edu/Sidebars/Study_Skills_Resources/cornellsystem.pdf

Before Class

Look over the material from a textbook or a review book. Read in advance; familiarize yourself with key concepts and vocabulary; review your notes from preceding lectures. Try to understand the material as much as possible. If there are questions, then lecture class will help answer them.

During Class

1. Record: Use notetaking column on right to record lecture notes using telegraphic sentences (which is a straightforward sentence that excludes unnecessary words. (Ex.Germ. invade Pol. 9/39.)) on a notebook. Notes should be only the most important aspects of the lecture. Also take notes of questions asked by the professor. If the professor thinks they are important to ask the class, then chances are they are important for the exam. The rest is fluff and is not necessary for learning the material. It is important to record the lecture (Supernote App – which gives you a clear and adequate recording) to help revise notes later.

When Recording:
* Number, title, and date each page. Include the professor’s name, section #, and chapter in book.

* When unsure of a word, leave it blank and fill it later.

* When unsure of a word, leave it blank and fill it later.
* Use lots of white space.
* Mark points of emphasis.
* Develop a shorthand system.
* Use colored pens.

*Make sure to record any assignments before leaving the room onto your planner. Try to get the assignments done ASAP. However, try to understand the content as much as possible so homework becomes more beneficial. Refer to the notes and textbook for understanding before delving into harder homework problems.

After class:

2. Questions and Cues: ASAP after class, formulate questions and cues based on the written notes. These written questions help clarify meanings, reveal relationships, establish continuity, and strengthen memory. It also helps with exam-studying later. Cues include categories and subcategories, vocabulary words, and important notifications for the future. Cues and keywords help distinguish between important and unimportant information. Ex: essential,in conclusion, futhermore. They also help link facts and ideas together to facilitate better learning.

3. Summarize: Use the space at the bottom of each page to summarize in your own words the notes on that page right after class or a few hours after class. If you don’t think a summary would help you, you could include the five main points of the notes or any questions that you still do not know the answer to. These questions could then be asked at the next lecture.

4. Recopy (Optional for Cornell Notes): Recopy notes from notebook to binder for better organization, neatness, and accessibility. The paper is formatted using Cornell format generator online. Also include charts and other supplemental material that may help the process. Use Supernotes app to retrieve recorded lecture to make recopied notes even better. Use different color highlighters to indicate important concepts. Once done, review them ASAP or before going to sleep on that day. Stay within 24 hours.

 3. Recite: After recopying notes, cover the notetaking column with a sheet of paper. Then, looking at the questions or cue-words in the left column, say aloud, in your own words, the answers to the questions, facts, or ideas indicated by the cue words. While reciting, write it down so that it improves retention. The more senses you use the more likely you are to remember what you read Triple strength learning: Seeing, saying, hearing. Quadruple strength learning: Seeing , saying , hearing, writing!!!Source: http://www.ctl.ua.edu/ctlstudyaids/studyskillsflyers/MemorySkills/recitingraisesretention.htm

4. Reflect: Reflect on the material by asking yourself questions, for example:

  • What’s the significance of these facts?
  • What principles are they based on?
  • What is the big picture?
  • How can I apply them?
  • How do they fit in with what I already know?
  • What’s beyond them

5. Review: Review your notes periodically. This is the only way to achieve lasting memory. Spend at least 10 minutes every week reviewing all your previous notes. If you do, you’ll retain a great deal for current use, as well as, for the upcoming exam. Try to incorporate different learning styles while studying/ reviewing: use flashcards, read them aloud, etc. Also, you only have to review them, so cramming is avoided.

Week or 2 Before Exam:

  • Use the time to go over notes that YOU DON’T KNOW. Refer to your test questions from the notes. Any that are not scratched off yet needs to be practiced. Once they are all scratched off, you are ready for the exam. 

Final Review Night Before Exam

  • Look over notes, questions, summaries. Always recite notes while reading them. No cramming necessary.
  • Go adequate sleep as usual

Exam Day:

  • Get a Good Breakfast. Relax during the day. You are ready for the exam!

Important Tips:

  • If you are still having trouble with studying, refer to the link: http://howtostudyincollege.com/2012/12/31/a-simple-how-to-study-fix/
  • Take frequent breaks. No longer that 45-60 minute student block.
  • If you are getting distracting while studying or not getting concentrated, then use the X-system method. Every time these things are happening, put a X-mark on a separate sheet of paper. After a while, you notice a lot of them in a single day. Use it as motivation to reduce the X-mark as much as possible to zero.
  • In reviewing notes, use the questions and summaries as “talking” or “starting” points for recitation. Go into the notes themselves only when you feel that you are not prepared to develop the questions and summaries.
  • Always refer back to the planner, calender, or schedule on iPhone or electronic device to update it and to do next assignment or study time.
  • Whenever a task is completed, always think of the following: “Next 2 things on agenda.” That way, it reduces procrastination.
  • If studying from a book or study guide, try to do practice repetition of what was read (at the end of a paragraph): Cover up the text and write in own words what was read. Reciting while writing is highly recommended.
  • Plan a study schedule one week in advance on your planner to follow. That way, you won’t waste time trying to decide what to study or do later on.
  • Plan a study schedule one week in advance on your planner to follow. That way, you won’t waste time trying to decide what to study or do later on.
  • Always try to get at least 8 hours of sleep a night, even on weekends and especially before exam day. Don’t studying with nervous classmates right before an exam because that could make you less confident in yourself.
  • Start studying early. Just because a testis a month away does not mean you shouldn’t worry about it until the day before. If you take 30 minutes a day (or more) to review your notes, you will be more prepared for the test. This helps store the information into long term memory.
  • Also, reciting the Cornell notes, especially the summaries and predicting exam questions, also puts information into the long term.
  • For cumulative exams coming up, focus on the unfamiliar material before the familiar material. If a class covered 5 topics since the last exam, then start studying the latest topic and work backwards from there. Plan 2 hours of active review for each topic spread over at least 5 days.
  • Use an outline form for your notes because it is easier to see how items correlate with each other and to see the main points of the notes.
  • If it is best to draw or graph something, then do it instead of writing it.
  • Each weekend allow yourself some time to review all the material you have gathered up to that point.
  • If it is best to draw or graph something, then do it instead of writing it.
  • Each weekend allow yourself some time to review all the material you have gathered up to that point.
  • Always sit in the front row to take notes. If late for class, try to sit as close as possible to the professor.
  • Remain up-to-date with the class material. It is imperative to take notes and recopying them within 24 hours of the class to avoid falling behind and having to do more work later on to catch up.
  • Write on one side of the paper to avoid overlooking material on the back of a sheet. USe the backside of paper for additional questions or information about the topic, but this side is optional.
  • Compare notes with a classmate soon after class to see if you missed any important points.
  • Do more listeing than writing.
  • USE INK! Notes in pencil will smear and are hard to read anyway. Be sure to use a large notebook.
  • Read your notes over as soon after class as possible to fix handwriting, spelling and clarity.
  • Underline the first main topic. Then write down, in list form but without numbers, the most important things he talks about. (Don’t try to make sub- topics and sub-sub-topics.) Keep on doing this until you find that he is talking about something else. Then you will know it’s time for another main topic.
  • Listen for signals. He’s almost sure to say something about “The first point I want to discuss today…”
  • Edit notes as soon as possible after the lecture, preferably the same day. Correct errors, fill in blanks, clarify information. Mark key words and concepts. Summarize and re-organize where appropriate.
  • Notes should consist of key words, or very short sentences. As a speaker gets side-tracked or goes on a tangent, you can go back and add further information.
  • Write down everything that is on the blackboard, not just what you feel is important. Make it less wordy, though.
  •  Have a uniform system of punctuation and abbreviation that will make sense to you. Use a skeleton outline, and show importance by indenting. Leave lots of white space for later additions.
  • If something is stressed as important by the professor, note it by a star or highlight the point.
  • Omit descriptions and full explanations. Keep your notes short and to the point. Condense your material so you can grasp it rapidly.
  • Don’t keep notes on oddly shaped pieces of paper. Keep notes in order and in one place.
  • Think a minute about your material before you start making notes. Don’t take notes just to be taking notes! Take notes that will be of real value to you when you look over them later.
  • Take accurate notes. You should usually use your own words, but try not to change the meaning. If you quote directly from the author, quote correctly.
  • Use different notebooks or binders if taking more than one class.
  • Pay close attention around the end of the lecture. Some speakers find themselves lagging behind and may cram the rest of the material during the last ten to fifteen minutes.Use the five-minute technique to review notes immediately after class. This gives students time to change, add, summarize, erase, or clarify information in the notes.

Forgetting:

· The greatest amount of forgetting occurs directly after finishing the
learning task! (46 % forgotten in one day)
· Forgeting is still sizable during the first fourteen days – (79% forgotten)
· Forgetting slows down after 2 weeks, but there is not much left to
forget! (82% forgotten after 21 days)
· How do you try to stop forgetting? Study skills!!

Remembering:

It has been said that we remember:
10 percent of what we read (passive)
20 percent of what we hear (passive)
30 percent of what we see and hear (passive)
70 percent of what we say and write (active)
90 percent of what we say as we do (active)

Source: Memory: http://www.northshore.edu/advising/pdf/memory.pdf

Styles of Note-taking

Many students and professionals jot down the most important ideas randomly; however, there is a method to the madness. Effective note-takers have used one of the five different methods for taking notes, including the Cornell, Outline, Mapping,Charting, and Sentence methods. The Cornell method makes it easy to take notes without recopying the most important facts. Dash and indented notes can come in handy in science and math related classes. Mapping involves the creation of a graphic representation of the facts presented during a lecture. Charting comes in handy when the lecture consists of chronological key points. The sentence method allows the note-taker to write down the most important points on separate lines, making it easier to read instead of large blocks of text.

Listening Skills

Eighty percent of everything acquired from a lecture comes through listening. Therefore, students must learn efficient ways to listen in order to take good notes. Listening requires the application of certain principles until they become ingrained in the note-taker. Students must prepare to listen by keeping up to date with the course curriculum. Read the chapter before attending the lecture to understand the information being presented. Listen for the main ideas and important details that supported them. A speaker typically pauses when giving the main idea, provides examples, and repeats what has been said. Others may change the volume or pitch of their voice to accentuate the point given. Be sure to write down all ideas and facts on the chalkboard or overhead projector.

Learn to recognize that the speaker is making an important point by:

  • pausing
  • giving examples
  • repeating what has been said
  • repeating the textbook
  • increasing volume or changing pitch of voice
  • taking more time on one area
  • adding class activities or worksheets
  • using body language (facial expression, gestures, posture, pace)
  • writing on the chalkboard
  • using direct statements (this is very important) or signal words
  • (examples: significant, most)

Ten Ways to Improve Listening
1. Find area of interest – maintain eye contact even if the subject appears boring. There will be
some information that will be useful.
2. Judge the content, not delivery. Find out what the speaker knows, not how he presents it.
3. Withhold evaluation until comprehension is complete – don’t become preoccupied with
rebuttal before idea is completely presented. Don’t listen defensively.
4. Listen for ideas – main ideas, central facts, organizational patterns.
5. Be flexible in notetaking.
6. Work at listening – spend energy to give conscious attention.
7. Resist distractions – a matter of concentration.
8. Exercise your mind – develop an appetite for hearing a variety of presentations difficult
enough to challenge your mental capacities.
9. Keep your mind open – be careful of emotional impact of certain words – don’t listen
defensively composing a rebuttal.
10. Capitalize on thought speed.
Speech speed – 100-200 words per minute
Thought speed – 400-500 or more words per minute.
Take advantage of differential – do not allow distractions during this time.

Ten Ways to Improve Listening
1. Find area of interest – maintain eye contact even if the subject appears boring. There will be some information that will be useful.

2. Judge the content, not delivery. Find out what the speaker knows, not how he presents it.

3. Withhold evaluation until comprehension is complete – don’t become preoccupied with rebuttal before idea is completely presented. Don’t listen defensively.

4. Listen for ideas – main ideas, central facts, organizational patterns.

5. Be flexible in notetaking.

6. Work at listening – spend energy to give conscious attention.

7. Resist distractions – a matter of concentration.

8. Exercise your mind – develop an appetite for hearing a variety of presentations difficult
enough to challenge your mental capacities.

9. Keep your mind open – be careful of emotional impact of certain words – don’t listen
defensively composing a rebuttal.

10. Capitalize on thought speed.
Speech speed – 100-200 words per minute
Thought speed – 400-500 or more words per minute.
Take advantage of differential – do not allow distractions during this time.

Ten Questions to Ask Yourself While Listening
1. What is he saying; what does it really mean?
2. How does that relate to what he said before?
3. Where is he going; what’s the point he’s trying to make?
4. How is that helpful; how can I use this?
5. Does this make any sense?
6. Am I getting the whole story?
7. How does this relate to what I already know?
8. Is he leaving anything out?
9. How does this relate to what I already know?
10. Do I understand what he’s saying or should I ask for clarification?

Ten BAD Listening Habits, by Ralph G. Nichols
1. Finding the subject uninteresting
2. Judging delivery, not content.
3. Allowing excessive emotional involvement
4. Listening for details, not central ideas
5. Using non-flexible notetaking
6. Paying poor attention to the speaker
7. Being easily distracted
8. Avoiding difficult material
9. Refusing to accept new ideas
10. Thinking about irrelevant topics

Three important findings from studies concerned with notetaking:
1. Notetaking helps you listen; it does not interfere with listening and
comprehension.
2. Students who study their notes using the recitation method remember one
and a half times more after six weeks than students who do not review.
3. Students who take no notes or do not study their notes forget approximately
80% of the lectures by the end of two weeks.

Test-taking Tips: http://www.northshore.edu/advising/pdf/test_taking.pdf

Good lecture notes must:
1. present a neat, attractive appearance.
2. indicate the main points of the lecture.
3. show the relationship of the details to the main points.
4. include enough illustrative detail to enrich notes and content.

Common Abbreviations for Notetaking to consider:

at: @, before: b/4, year: yr, question: q or ?

learn: lr, within: w/in, i.e.: that is

Sources: http://www.recordnations.com/articles/record-keeping-students.phphttp://library.kcc.hawaii.edu/sos/resources/top_10_notetaking_tips.htmhttp://www1.chapman.edu/arc/goodnotes.html,

http://www.luc.edu/advising/pdfs/Exam_Preparation.pdf,

Listening and Notetaking Notes: http://www.northshore.edu/support_center/pdf/listen_notes.pdf

Example of a good Cornell Note (for WWII): http://www.uhv.edu/ac/study/pdf/cornell.notetaking.pdf

Chemical Synapse

At the end of an axon are closed calcium voltage gated channels (similar to K+ and Na+). If positive enough near the voltage gated channel (or high concentration of calcium on outside), it open up and Ca2+ flood into cell. The calcium ions then bond to other proteins.

Synapse: Place where axon meets dendrite (connection point). Pre-Synaptic neuron is at the end of the axon. Post-Synaptic neuron is at the end of the dendrite. Synaptic cleft is the place b/w the two neurons.

At the pre-synaptic neuron are vesicles that that contain neurotransmitters that they train. ‘

After the flood of calcium ions, these ions bond to SNARE proteins in the cell. These proteins snare the vesicles to the pre-synaptic membrane. The ions change the SNARE protein conformations and the proteins bring the  vesicles closer to the membrane by pulling both membranes closer together. The vesicles then undergo exocytosis and release neurotransmitters (like Acetycholine)  into synaptic cleft outside the cell.

These neurotransmitters then bond to post-synaptic membrane of the dendrite at ligand-gated sodium ion channels. It then triggers neurotransmitter-gated channels to open as Na+ channel get excited with the positive charge. Membrane potential is more positive as Na+ ions flood in (diffuses). There is an electrotonic effect at the axon hillock. Action potential occurs as the potential at point increases (when membrane potential reaches threshold level).

If the K+ voltage-gated channel was triggers, then K goes out of cell due to concentration gradient being high inside cell. This is an inhibitory chemical synapse.

Khan Academy: https://www.khanacademy.org/science/biology/human-biology/v/neuronal-synapses–chemical

McGraw-Hill Animation with Quizzes:

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__chemical_synapse__quiz_1_.html

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__chemical_synapse__quiz_2_.html

Transmission Across a Synapse: http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__transmission_across_a_synapse.html

Anatomy of a Neuron and Saltatory Conduction

Neurons have 3 principal regionals: a nucleated cell body, dendrites, and an axon.

The cell body is the “nutritional center” of the neuron and contains densely staining areas of rouge endoplasmic reticulum.

Dendrites are thin, branched processes that extend from the cytoplasm of the cell body, providing a receptive area that collects and transmits electrical impulses to the cell body.

The axon is usually a longer process that conducts impulses away from the cell body.

Nerve impulses originate in the axon hillock, an expanded regions where the cell body and axon meet.

Schwann cells (specialized glial cells) form the neurons’ myelin sheaths outside the brain and spinal cord. In the CNS (brain and spinal cord), they are called oligodendrocytes). The glial cells wrap the axon in layers or sheaths of tightly compacted plasma membrane, which form the myelin. Each new layer of Schwann cells overlaps the previous ones.

Gaps of axon are exposed b/w adjacent myelinated segments called nodes of Ranvier. They are important to the speed at which a neuron transmits messages. At the nodes, there are Na+ and K+ gated channels that can open to allow Na+ to come in. Once its in, it can jump from one node to the next rapidly. So, it doesn’t have to wait for voltage gated Na+ channels to open along the axon.

The myelin sheath is an insulating outer layer on the axon. It acts as an electrical insulator, allowing the nerve impulse to travel quickly and passively b/w the nodes of Ranvier. Myelin sheath also prevents electrical charages to leak through the membrane.  But the myelin sheath is bare of voltage-gated channels. At the nodes, impulses are actively regenerated. This is b/c the myelin sheath prevents action potential from continuing so a local electrical circuit is generated. The circuit stimilates action potential at the next node, which is why there is a jump.

So, the nerve impulse jumps successively from one node to the next in a type of transmission called saltatory conduction (saltare = to jump). It is around 100 times faster than signal or action potential conduction in unmyelinated axon of the same diameter.

Action potential conduction (unmyelinated sheath): Basically, as long as the action potential occurs somewhere on the axon, it will run all the way down the axon.  Here’s a figure that shows this:

apconduct.jpg (54553 bytes)

Saltatory Conduction: This manner of conduction is a lot faster because only the nodes of Ranvier are involved in action potential conduction.

In order for an action potential to occur, you saw that sodium and potassium ions have to move across the axonal membrane.  Remember?   Well, wherever the Schwann cells (in yellow in the animation) wrap around the axon, the sodium and potassium ions cannot cross the membrane; the Schwann cells wrap too tightly around the axonal membrane for there to be any extracellular space underneath them.  Therefore, the only place that an action potential can occur is at the node of Ranvier– the space between the Schwann cells.  Because of this, the action potential seems to jump from node to node along the axon.  “Jumping” is what the word “saltatory” means.

    So, saltatory conduction is when the action potential jumps down the axon from node to node.

Pearson Animation: http://wps.aw.com/bc_goodenough_boh_3/104/26721/6840613.cw/content/index.html

Interactive Biology: http://www.youtube.com/watch?v=M3u7v0RXkok

Saltatory conduction (myelinated sheath) vs. Action potential conduction (unmyelinated sheath): http://www.brainviews.com/abFiles/AniSalt.htm

Wisegeek: http://www.wisegeek.org/what-is-the-saltatory-conduction.htm

Action Potential in Nerve Cells

Action Potential in Nerve cell: Moving Depolarization of axon

Resting Potential = Inside of cell is negative (-) charged; outside of cell is positive (+) charged. Na+ is outside, K+ is inside.

Polarization = Resting Potential; inside of cell is (-) charged.

Depolarization (Action potential) = Inside of cell is negative (-). K channel is closed, Na channel is open; Na+ flood into cell causing cell to become  (+) charged on inside.

Repolarization = Return to resting potential. Na channel is closed and K channel is open; K+ flood out of cell and and restore (+) charge outside cell. Inside of cell becomes polar ( or negative charged). NA+/K+ pump fully restore the concentration gradient by transporting Na+ out of cell and K+ into cell to resting membrane potential.

Useful Links for Animations:

Very useful animation from Harvard: http://outreach.mcb.harvard.edu/animations/actionpotential_short.swf

Animation of AP: http://bcs.whfreeman.com/thelifewire/content/chp44/4402s.swf

Animation of AP: http://bcs.whfreeman.com/thelifewire/content/chp44/4402002.html

Wisegeek: http://www.wisegeek.com/what-is-action-potential.htm