Learning Tissues Bird by Bird

What?!  Bird by bird?

Yep—that's the best way to begin learning how to distinguish the various tissue types of the body.

The bird-by-bird approach to learning anatomy is based on two major concepts, described here.

Chunk the List

The first was described by author Anne Lamott in her book Bird by Bird: Some Instructions on Writing and Life:

"Thirty years ago my older brother, who was ten years old at the time, was trying to get a report on birds written that he'd had three months to write. It was due the next day. We were out at our family cabin in Bolinas, and he was at the kitchen table close to tears, surrounded by binder paper and pencils and unopened books on birds, immobilized by the hugeness of the task ahead. Then my father sat down beside him, put his arm around my  brother's shoulder, and said, 'Bird by bird, buddy.  Just take it bird by bird.'"

Wow—doesn't that sound just like the feeling you have when you are given a list of human tissues to learn in your A&P course?  With crazy names like nonkeratinized stratified squamous epithelium, specimens that look like the abstract art exhibit at the art museum, and an insanely short time frame to master them all, of course it feels overwhelming.

Really, that's the best way to tackle the tissues.  Just get started!  And take them one by one, rather than thinking about the whole long list of them facing you.  You'll find that by chunking the list this way, it's not so paralyzing.  It sounds overly simple—perhaps even a bit silly—but it really works!

Focus on Unique Characteristics

A while back, I wrote a post called Trouble with Tissues? in which I briefly described a method for learning tissues based on how birders learn how to tell one bird from another when out birdwatching:

The introduction to my Field Guide to the Body at the Lion Den website compares studying tissues to what birders do when they identify wildlife in the field. Take a look at that brief analogy, including examples of how to apply it to histology, for helpful tips on making this topic easier. If you're using any of my lab manuals in your A&P course, you can apply this technique directly by looking at the Landmark Characteristics boxes scattered throughout the tissue exercises.

To summarize this method, you simply look at what makes each tissue different from other tissues just as you would when learning the many different types of sparrows live in the state park:

• Field marks—physical characteristics that distinguish one type from another.  All sparrows are LBJs (little brown jobs), but each species has a unique characteristic such as a beak color or streak on the cheek that sets it apart from the others.  Likewise, each tissue type has one or more physical characteristics—such as cell shape or fiber type or cell arrangement—that make it stand out from all other similar tissues.


• Range—if I look out my window and see a penguin, I know I need my eyes examined.  Because I live in Missouri, where penguins live in only in zoos.  So I can identify birds in part by which birds live in or visit my region.  Bird guides list ranges for this reason—to help you figure out which bird the one in your yard could be.  If you learn the locations of tissues, that helps you figure out where to look for them.  For example, look for most epithelial tissues on surfaces, look for cardiac muscle in the heart.  If you are looking at a tissue sample from the arm, then don't expect that muscle tissue to be cardiac muscle—it's instead likely to be skeletal muscle tissue,


• Habitat—Besides knowing which region a bird is likely to be found, it also helps to know what kind of habitat it prefers.  Look for forest birds in the forest and look for shore birds, well, along the shore.  With tissues, if you know that if you are looking for irregular fibrous tissue, look under epithelium—there's always some there.


• Behavior—Behavior is function.  When identifying birds, it helps to know how they fly (do they soar like vultures or hover like hummingbirds?).  When identifying tissues, it helps to know their functions.  If you know that fibrous connective tissues are often supportive in function, that will help you find them.  If you know that smooth muscle tissue compresses the hollow part of hollow organs, you know where to find them—within the walls of hollow organs such as digestive organs.

Not Just for Tissues

This method also works well for learning bones and bone features, muscles of the body, nerves, digestive organs, and more—any of the "birds" of the body!

Want to know more?

Trouble with Tissues?

• Kevin Patton.  The A&P Student. 28 September 2010.
• Outlines tips for studying tissues in the A&P course.
• my-ap.us/14OoEVR

Field Guide to the Human Body

• Kevin Patton. Lion Den. Accessed 7 September 2014.
• From my study tips website, this page introduces the "birding" analogy to studying human structures.
• my-ap.us/1AokMsw

Bird by Bird: Some Instructions on Writing and Life

• Anne Lamott. Anchor. First published 1 January 1994.
• Great book.  Great author. That is all.
• my-ap.us/Yon5jT

Survival Guide for Anatomy & Physiology

• Kevin Patton. Elsevier. Oct 18, 2013.
• Tips and techniques for studying A&P, including tissues, mentions the birding analogy.
• my-ap.us/16aa5zg

Powers of Ten

In A&P, many students have hard time wrapping their heads around the size of things.

For example, how many of us really have a good grasp of how small a cell really is, or a protein molecule within a cell, or an atom within the protein?  Or the relative size of tissues compared to individual cells—or compared to an organ?

And we are continually "zooming our focus" in and out among levels of organization—atoms and ions, molecules and crystals, organelles, cells, tissues, and organs.

Add to that the fact that the units of measurement used to describe the size of things are in the metric system (SI), which is based on powers of ten. That is, we use a measuring system based on units that very by a factor of ten—units are multiplied or divided by ten, then another ten, then by ten again.

Add to that the frequency of discussion of pH units, which on the surface seem to go up or down by single units—but in reality a change from one pH unit to the next is a change in hydrogen ion concentration by a factor of ten.

This nifty little video can help us wrap our heads around the concept of powers of ten.  It may help us in navigating the world of the human body. Click here to see the helpful material that accompanies the video.

 

Source: my-ap.us/1aFctxP

DNA image credit: 3Dscience

Trouble with tissues?

I don't think I've ever met a person who could identify tissues of the body on sight on their first day of trying. And yet many A&P students get frustrated just because they can't "get it" after only one day of trying. Identifying tissue types by sight is difficult for everyone, at first—for  several reasons.

First, each example is unique. No two examples look exactly alike, just like no two fingerprints look exactly alike.So you have to learn to look for patterns. And you can't do that until you've looked at a lot of examples. And that takes time—and a lot of practice.

Second, not all examples are stained in exactly the same way. Even when the same general type of staining is used, a lot depends on the quality of the sample, the quality of the stain used, and how well the preparer did their job. So again, you have to look for patterns. For example, stratified squamous epithelium can be found in wildly different colors, depending upon which type of staining technique is used. But no matter what the color, the pattern of flattened cells near the free edge, progressing to cuboidal and perhaps even column-shaped cells further away from the free edge, will still be present.

Third, when you look for patterns you have to remember what part of the pattern is important. You also have to remember that many patterns are very similar, so you have to remember how to tell them apart. For example, dense fibrous connective tissue can look a lot like fibrocartilage at first glance. You have to learn to look for the little white halos around the cells in fibrocartilage that tell you that the cells are within lacunae (spaces).

Oh, did I mention that practice, practice, practice is important?

Tissue identification really isn't as hard as it first seems. It really is mainly just a matter of putting the time into practicing.

Here are some tips for getting the most practice time in during the short time you have studied tissues:

• Spend as much time in the lab as possible. If there are open lab times available, by all means take advantage of it.
  
  
• If there is a learning center available with tissue specimens spend as much time as you can with them.
  
  
• Use the examples published in your textbook and lab manual, or any other resource (such as a Brief Atlas of the Body),to practice identifying tissues. Cover up the labels and see if you can identify them. Make a photocopy of the images, cutaway or cover-up the labels, and test yourself.
  
  
• Ask your instructor for other sources of practice images. Sometimes, someone will have taken photographs of the specimens used in your class. This is a good resource for practicing.
  
  
• There are a lot of online resources for practicing tissue identification. Here are a few of my favorites – you can find many more by searching the web using key terms such as "tissues," "histology," and similar terms.
  
  
• LUMEN
  [Loyola University's famous histology site; includes lessons on histology]
  
  
• Blue Histology
  [Histology site at School of Anatomy and Human Biology, University of Western Australia]
  
  
• Dr. Stephen Larsen's Channel (YouTube)
  [Dr. Larsen walks you through a variety of specimens as they are seen under the microscope.]
  
  
• The A&P Professor Free Image Library
  [My site for A&P teachers includes links to free images of tissues that you can use to practice histology.]
  
  
• Use flash cards (study cards) with photocopies of tissue specimens or printouts of digital images. See my recent blog article for a video on how to use flash cards in this manner.  Mosby's Anatomy & Physiology Study and Review Cards includes some histology cards along with all other topics in A&P.
  
  
• Try to study a little bit several times each day, rather than a few long sessions several days apart. Constant practice is what works best.

The introduction to my Field Guide to the Body at the Lion Den website compares studying tissues to what birders do when they identify wildlife in the field. Take a look at that brief analogy, including examples of how to apply it to histology, for helpful tips on making this topic easier. If you're using any of my lab manuals in your A&P course, you can apply this technique directly by looking at the "Landmark Characteristics" boxes scattered throughout the tissue exercises.