Mechanism of Cracking Knuckles

It never fails—somebody always asks about what's going on when knuckles crack when we get to the topic of articulations.

Recently, researchers used modern MRI techniques to demonstrate exactly what is happening—a process first described in the 1940s.  As joint surfaces separate, the changing tension in the synovial fluid causes a vapor pocket or "air bubble" to form in a process called cavitation.

The recent research proved that the popping sound typical of cracking a knuckle is produced as the vapor pocket forms. It also disproved the theory that the popping occurs when the bubble collapses.

What can we use from this in teaching undergraduate A&P?

• You'll now always be ready for that inevitable "what causes knuckles to crack?" question when discussing joints in your A&P course.


• Consider having a slide containing the media offered below to show students.


• Discussing joint-cracking mechanisms engages students in a subject that may not immediately interest them.


• Joint-cracking allows us to reinforce concepts of fluid dynamics in the context of synovial joints.


• Consider stimulating some critical thinking by asking "what could cause a cracking sound in a cartilaginous or fibrous joint?"   (Hint: think "fracture" as cavitation would not occur where there are no fluids)
• Do a demonstration by hitting a glass bottle full of water with a rubber mallet (see the embedded video below)
• I've done this with an unopened glass bottle of ketchup by upturning it and hitting the base with my palm

Want to know more?

• Real-Time Visualization of Joint Cavitation
• GN Kawchuk, et al. PLoS|ONE. April 15, 2015 DOI: 10.1371/journal.pone.0119470
• The original journal article. Includes downloadable images and PowerPoint slides, plus a link to a video showing the MRI results.
• Article my-ap.us/1JL9d4N
• Video my-ap.us/1CLrLgz
• PowerPoint slide my-ap.us/1DIRxpQ
• Image file my-ap.us/1cwKuGs


• Researchers pull fingers to solve why knuckles crack | Finding bursts bubble of popular theory
• Tina Hesman Saey Science News April 15, 2015
• A plain-English summary of the new work on knuckle cracking with an embedded video (see below)
• my-ap.us/1J4cGKP

Check out this video from the research article

Here's a video of the glass bottle demo of cavitation

Photo credit: Kawchuk et al.

Want to fold some proteins?

In a previous post, I proposed that A&P students should be aware of the basic elements of protein folding.  To follow up, I'd like to mention a interesting phenomenon related to protein folding and "citizen science" using an online game called Foldit.  


The Foldit game is an online puzzle game in which anybody can try their hand and finding which way a given protein folds most efficiently.  Interestingly, this has proven to yield useful results for biochemists not obtainable by traditional methods.

You may want to mention the Foldit game to students.  I've already posted it at my blog The A&P Student.

Want to know more?

Online Gamers Achieve First Crowd-Sourced Redesign of Protein
Jessica Marshall & Nature magazine
Scientific American Online January 22, 2012
[Brief article about recent redesign of a protein by online gamers using Foldit. Original paper published in Nature Biotechnology]
my-ap.us/wRK2bV

Foldit Online Protein Puzzle
Scientific American Citizen Science accessed 23 January 2012
[Brief description of the online game Foldit and the goals of the project.]
my-ap.us/zIV75F

Foldit - Solve Puzzles for Science
[Direct link to portal for the game Foldit]
my-ap.us/wfRQPF

First human brain map unveiled

Today NewScientist reported that the world's first computerized map of the brain was unveiled last week by neuroscientists at the Allen Institute for Brain Science.

The FREE interactive brain map must be downloaded and installed on your computer at http://my-ap.us/f8Rabf   It's fun . . . you should try it! 

You can see both of two brains used to produce the maps and check which parts of the brain you want to see.  Each is shown in a different color and you check and uncheck brain parts as you explore.  For example, you can visualize just the cerebral nuclei, then add in the cerebral cortex.  You can also click on each part of the cortex and it will highlight (and name) the particular gyrus or region that you are on.

There are far more features than I've had the time to explore . . . and far more than I'll need to use in the classroom to help my students visualize the brain's structure.

All these richer features are available because it's meant as a research tool rather than a teaching tool.  The new map can show the biochemistry and gene expression at various sites based on in depth studies done on two human brains, for example.  But you don't have to use any of the richer features.

One of many interesting and useful tidbits of information that has come out of the research end of the project is that there is a 94% similarity in the biochemistry of the two human brains used int he study.

Another interesting fact is that at least 82% of all human genes are expressed in the human brain.  (Except perhaps in mine, especially on Fridays.)

While exploring the website at Allen Institute for Brain Science I also stumbled upon a nifty, interactive tool that I'll also probably use in my A&P course.  This FREE tool allows you to view different planes of the brain simultaneously while navigating around the brain.  I imagine that this tool would be fun to use in class to visualize anatomical relationships of the brain as students themselves navigate around and answer their own questions about the general nature of brain structure.


Want to know more?

World's first human brain map unveiled
H. Crawford
NewScientist published online 15 April 2011
[Brief news synopsis with images of applications of the new brain map]
http://my-ap.us/dRY1Qy

Allen Institute's online MRI explorer
[FREE interactive tool that allows you to explore a human brain MRI to visualize brain structure at different levels that you control.] 
http://my-ap.us/hjGa7c

Allen Institute's download page for Brain Explorer 2
[FREE interactive tool that allows researchers to locate biochemistry and/or gene expression at specific brain locations.] 
http://my-ap.us/fDppYG

Google Body Browser

My editor Jeff recently pointed me to a story about Google's recently launched Body Browser.  I was amazed at this latest creation of Google Labs.

The Body Browser is a FREE online tool that you and your students can use to explore the anatomy of the human body in a "virtual dissection" format.  Using the familiar Google Maps navigation tools, you can . . .

• Peel (or fade) away layers of the body . . . removing the skin, then muscles, then bones, to reveal the internal organs
  
  
• Select systems (skeletal, muscular, nervous, cardiovascular) to view
  
  
• Click on any structure to show its label
  
  
• Type the name of any structure in the search box to find it in the body
  
  
• Tilt, zoom, turn the body to a variety of positions to see organs in more views that usually available in a textbook, atlas, or chart

The Body Browser runs inside any WebGL-enabled browser, meaning that you don't have to worry about having the latest Flash or Java plugins installed.

I think Body Browser a is a great FREE tool for A&P students to have access to an online model of the human body that can be used for a beginning study of anatomy.  Because it allows the user to type in the names of organs for which they are looking, you don't need to worry about it being too high (or too low) a level for your course.

There are a few minor limitations of the Body Browser:

• The only available specimen is female (that is, there is no male specimen available to complement the female specimen)
  
  
• The specimen is partially clothed.  Although one can see some of the underlying surface structures as the "skin" layer fades back, it's not the same as seeing these structures clearly.  An odd feature that makes certain regions of the body "off limits." (I've seen some hacks to fix this, but none of them work for me using the Chrome browser)
  
  
• Some of the organs are roughly rendered, so it's not as detailed (at least in some areas) as you may like to see
  
  
• Only a few systems can be shown in entirety.  Some useful system views that are missing are the lymphatic system and the respiratory system
  
  
• You cannot select or hide individual organs for display
   
• I could find no documentation or even a help button (pretty typical of Google Labs resources)

Even with some minor limitations, Body Browser is still a fantastic study and teaching tool.  As an A&P professor, you might use Body Browser as . . .

• a presentation tool during a class lecture or discussion to demonstrate the location and structure of specific organs
  
  
• you could use it live or you could record a session with Jing or similar recording tool and use the pre-recorded exploration
  
  
• a tutoring tool with which you can send the URL of a specific view (perhaps with a label) to a student or group of students
  
  
• a testing tool with which you can create specific views that can then be used to test from on a quiz, test, or lab practical . . . perhaps using a screen capture tool such as Jing
  
  
• alternative lab model to use along with, or in place of, physical models in the lab
  
  
• it may be useful as a reference to side by side with a laboratory model
  
  
• use it in place of a laboratory model in a distance learning course

I'll be listing some ideas for student  uses of Body Browser at my blog The A&P Student.

Do you have some other ideas for using Body Browser in an undergraduate A&P course?  Just use the comment feature and share your ideas with us!

Check out this video to see a demo of the currently available features of Body Browser

TeacherTube

Here's another free source of videos you may be able to use in your A&P courses . . . it's called TeacherTube and it's sort of like an educational version of YouTube.

In my recent blog article Using YouTube in A&P, I revealed some of the benefits of using YouTube in your course . . . or even creating YouTube videos. Click here to see my own fledgling YouTube channel.

My friend Dave Willmore, one of our distance-learning gurus here at SCC, suggested that I also take a look at TeacherTube. I'm glad I did! Although its not nearly as huge as YouTube, this site has the benefit of being all about teaching and learning. Therefore, the videos are more or less already pre-filtered if you are looking for educational material. You can even select "college" or "secondary" levels as you sift through your search results to get material meaningful for your own students. When users upload their videos, they can also attach support files such as handouts, quizzes, worksheets, etc.

Apparently, the terms of use at TeacherTube are a little more favorable to content owners than are the terms at YouTube . . . but why don't we let our attorneys figure that out for us, eh?

Visit my TeacherTube profile.

If you find any good demos, tutorials, animations, or other gems at TeacherTube, please post a "comment" on this article with a link to the video . . . share and share alike.

[If you don't see the video viewer in your newsletter or feed version of this article, please go to The A&P Professor blog site to view it. Want to learn how to embed YouTube videos in your blog, website, or Powerpoint? Check it out at The A&P Professor website.]

FREE lab simulations

How about some FREE online laboratory simulations?

Howard Hughes Medical Institute (HHMI) offers FREE Biointeractive activities at their website, including these virtual labs that may work in your A&P course:

The Cardiology Lab

The focus of this lab is on heritable diseases of the heart. You are cast here as a virtual intern to accompany a doctor examining three different patients. Each patient is examined using more than one diagnostic tool, and at each stage, the doctor will invite you to examine the patient yourself and ask for your opinion.

The Neurophysiology Lab

Record electrical activities of individual neurons while you deliver mechanical stimulus to the attached skin. Inject fluorescent dyes into the neurons to visualize their morphology. Identify the neurons based on the morphology and the response to stimuli, comparing them to previously published results.

The Immunology Lab

Components of the immune system called antibodies are found in the liquid portion of blood and help protect the body from harm. Antibodies can also be used outside the body in a laboratory-based assay to help diagnose disease caused by malfunctions of the immune system or by infections.

This virtual laboratory will demonstrate how such a test, termed an enzyme-linked immunosorbent assay (ELISA), is carried out and show some of the key experimental problems that may be encountered.

These labs are also listed along with more FREE ONLINE STUFF at The A&P Professor website.

[Lab descriptions are from the HHMI Virtual Labs web page]

Quick and easy narrated screen captures

My friend Tom Lancraft recently shared with me some short videos outlining how to use the new (to me) ANGEL platform we are adopting for our HAPS Institute courses. He used FREE software called Jing.

I was intrigued by how fast he was able to produce these, then quickly email us a link to the finished demo. So I checked it out and tried it myself (of course). What a great (and EASY) little program to quickly put together a narrated screen capture to send to students or colleagues that need help that is better seen and heard.

Here's a sample of a little Jing presentation that I made in just five minutes:

http://screencast.com/t/oXCOFdnK7S

My sample has a small webcam shot in the corner, which was done by merely placing my webcam capture window alongside the browser window I wanted to demonstrate. To show you how flexible this approach is. Probably most of the time, you'd just use the browser window alone. Or PowerPoint screen, or lab software screen, or whatever.

If you want to learn more about Jing, check out this recent posting in my blog The Electronic Professor:

Jing screen-capture service
Kevin Patton
The Electronic Professor 19 March 2009

Do you have experience with Jing or some other way of making video demos? Questions? Then use the blog's *Comments* feature to connect with the rest of us!

And don't forget my FREE software page at The A&P Professor website!

Video version of the periodic table!

I know, I know.

Not many of us spend a lot of time in A&P going over basic chemistry.

I usually go over the essential concepts from inorganic chemistry, what's an ion, what's pH, polar and nonpolar covalent bonds . . . and then some essential facts about the major classes of biomolecules encountered in A&P.

Very seldom do I spend any great time using the period table of elements, other than to point out where iron is, or hydrogen . . . or the fact that very few of the elements listed there even play a role in human biology . . . and usually just because there happens to be a big honking periodic table on my classroom wall.

But I do occasionally stress the particular and peculiar characteristics of certain elements. For example, I'd love to have a balloon full of hydrogen with me to show how light it is . . . and a match to show how explosive it is. But that'd be impractical for several reasons . . . including the fact that I simply don't want to spend a lot of time on a small point.

Now I have another option. The University of Nottingham has a Periodic Table of Videos available FREE online. I can access any of the short videos to use in my class . . . or I can link to them for my students to access.

Each video is short . . . and you could simply use the few seconds you need.

And because the videos are posted at YouTube, you could embed a video or two in one of your webpages. [NOTE: To learn how to embed YouTube videos visit the YouTube page at The A&P Professor website.]

This collection is probably a lot more useful for a chemistry course . . . but you might find one or two uses in your A&P course.

Here's a sample:

Body Painting

Introduce body painting into your A&P class?!

I don't know . . . I'm not so sure this would be a big hit in my rather conservative community if word got out that our students were doing body painting in class!

But an article in the current issue of Anatomical Sciences Education (ASE) titled Body painting as a tool in clinical anatomy teaching has me thinking that maybe it's a good idea. The author, Paul G. McMenamin used body painting in his anatomy class to help his students learn about muscles, nerves, dermatomes, joints, bone markings, and surface projections of various internal organs by using this method of instruction.

McMenamin allowed students to work in single- or mixed-gender groups and gave them the option of working behind a screen. He found that gender and cultural issues never seemed to be an issue with his students.

He found that these exercises were very effective, and were perceived by students as being effective, in learning anatomical concepts. McMenamin cited the multimodal and interactive aspect of this method as probable reasons for the demonstrated success of body painting as a learning tool.

Click this link Body painting as a tool in clinical anatomy teaching to access the abstract of this article FREE of charge. (See note below for access to full article.)

Have any of you tried a similar method? Share your experiences with the rest of us by clicking the Comments link at the end of this article. (Or send it to me and I'll post it here or on The A&P Professor website if appropriate.)

[NOTE: Wiley InterScience, publisher of ASE, offers the journal FREE to institutions for a limited time during the journal's inaugural year. Click here for information to pass on to your college library to get the journal FREE!]