Cell and Tissue Biology

Atlas Demo

TheCOM-UIUC Histology web site includes written laboratory exercises that guide you through the slides in the atlas. This demonstration will familiarize you with the altlas and the navigational techniques used in the labs.

Image Size

Click on the link below to bring up an image from the atlas.

Slide w84 Spinal ganglion, rat

There are three images sizes available. If the image is either too big to fit completely within the frame or is too small to fill the frame, switch to a different imagesize. Do this by clicking on one of the image size links which appear as [S], [M], or [L] just above the image. NOTE: The largest image size may slow down the performance computers with less than 64 Megs of RAM. If images are loading slowly, try the medium images instead.

A trick that might permit you view the larger (higher quality) images is to minimize the screen space occupied by your browser program. For Internet Explorer go to the "View" drop-down menu and select "Toolbars > Customize..". Select the "Full Screen" tool from the available buttons window, then click "Add". The "Full Screen" button should now appear on your browser toolbar and can be used as a convenient toggle to minimize the screen space occupied by the brower in just one click.

Basic navigation

The image now on your screen is a 12x view of a microscopic slide that shows approximately what would be visible using your naked eye. You can always return to the lowest power view by clicking on the icon/thumbnail located at the upper-left corner of the control bar.

You will notice that two rectangles overlie the specimen. These represent links to higher-magnification views.

The empty box on the control bar (next to the yellow magnification box) is a drop-down menu that changes dynamically with each view to indicate (1) the identified histological features (these are referred to as "objects"), if any, in that view, and (2) links to higher magnifications. Click on the down arrowhead inside the drop-down menu to see that two links exist. Select link [2] from the drop-down menu by clicking on the text "Link 2 (22 objects)". You will see that the other rectangle disappears, and that the rectangle corresponding to the active link has changed color.

Click anywhere within the rectangle to be taken to the higher-power view. Notice that the number in the yellow magnification box has increased to 50x. Open the drop-down menu by clicking on the down arrowhead. You will see that three labeled objects are listed, dorsal root ganglion, proximal nerve branch, and peripheral nerve branch. Also notice that there is a link to yet another higher-power view.

Select and then click on "Dorsal root ganglion" from the drop-down menu. Notice that a region is highlighted by a color overlay and that the corresponding object name is pronounced, providing you have loudspeakers and a sound card in your computer. Now click anywhere within the highlighted region. You will see a new window appear with a short description of the structure. (The voice and description window are under construction. One or both features may be missing for some objects.) Remove the description window by clicking on "Okay." Try selecting the other identified objects from the drop-down menu and then view their descriptions.

Click on "link [1] (19 objects)" from the drop-down menu and click within the rectangle to go to a view at 250x. Verify that three objects are identified in this view. Click on "Sensory neurons." Notice that several of the sensory neurons, but by no means all of them, are highlighted.

Select and click on "link [1] (10 objects)" from the drop-down menu, and click within the rectangle. You are now looking at a 1000x image.  Scroll up and down the drop down menu list and notice that there are 10 labeled objects, but no links to higher magnification images.

Select and click on each of the identified objects from the drop-down menu in turn. Remember each time to view the object description by clicking within the highlighted region, or if the object is indicated by an arrow, by clicking directly upon the arrow. You can test yourself by removing the highlighting from an object to make sure that you can still identify it. To remove the highlighting select "- - -" from the drop-down menu at the end of the identified objects list.

There is a short-cut to navigate rapidly among links. We use this method of navigation extensively in the laboratory exercises. Click on the thumbnail to go to the lowest power view. Put the mouse pointer over each of the two rectangles in turn. You will notice that the drop-down menu indicates the link number that the mouse pointer is within. Clicking within that rectangle will take you directly to the corresponding view. Now follow links [2,1,1] by clicking on each in turn. You should have arrived at the same 1000x view that you were looking at previously.

Mouse-over mode

There is another mode for viewing labeled objects within the atlas which we call "mouse-over." Mouse-over mode is activated automatically for some images, including the one that you are looking at now, and this is indicated by the filled in "Mouse-over" radio button on the right side of the control bar just above the image. For other views (those that contain links to additional views), you must activate "Mouse-over" mode by clicking on the "Mouse-over" radio button. Now use the mouse to slowly drag the mouse pointer over the image to browse it. You will notice that when the mouse pointer is over a labeled object, that object is highlighted, its name is pronounced, and its identity is given in the drop-down menu. In some instances objects are identified with arrows pointing at them. In these cases, a response is triggered when the mouse pointer is directly over the arrow, not over the object. In mouse-over mode you may click on a highlighted object, or directly upon the arrow indicating an object, to display the object description. Don't forget to close the description window by clicking on the "Okay" button. Mouse-over mode is a good way to review what you have learned.

Exit mouse-over mode by selecting either an object or "- - -" from the drop-down menu, or, if there are further links available within the image you are viewing, by clicking on the "Links" radio button that is located just to the left of the "Mouse-over" radio button within the control bar.


Clicking once upon the "Zoom-Out" button on the control bar. (go ahead and do it) will take you to the next-lower magnification. Once there, click within the other rectangular box, link [2], and identify all the labeled objects.

Where am I?

If you lose your orientation when looking at a high magnification view, click on the "Where am I?" link from the control bar (go ahead and try it now). A new window containing the lowest magnification image will open with a flashing colored rectangle indicating the location of the higher magnification view. Sometimes the rectangle will be very small, but the flashing will help you to locate it. Close the "Where am I?" window by clicking on the close-box (marked by an "X") at the upper right.

Going back quickly

Now click on the thumbnail at the upper left-hand corner of the control bar. This returns you in onw step to the lowest magnification view. Notice that the number of hhigher magnification links to is indicated in parentheses next to the "Links" radio-button Open the drop-down menu and select link [1]. (We have just explored link [2] in the exercise above.) Now click on the red rectangle corresponding to link [1] and proceed to higher magnifications.


Clicking on the "Objects" link (try it now) brings up an alpabetical list of all identified objects in the atlas and links to views in which those objects are identified. Click on "Acidophils," and then on the thumbnail of slide w97a. You will be taken directly to a high-power view in which the acidophils of the hypophysis are labeled. Use the drop-down menu to highlight the acidophils.


Suppose you want to find views containing a particular object, say a nucleus. Click on "Search" at the top of the control bar, enter "nucleus" in the text window on the "Search" page and click the "Submit" button. A list of slides and objects including the word "nucleus" is returned. Scroll down the list to "Oocyte nucleus" and click on it. Click on either thumbnail to go directly to a higher-power view in which the nucleus will be highlighted for you.

You should experiment with various ways of carrying out searches within the atlas. Because all the images, objects, descriptions and sounds are contained in a relational database, the search capabilities are powerful and rapid.


The slide numbers beginning with w are animal specimens prepared in our laboratory. The animals from which these specimens were taken were perfused under heavy anaesthesia. The fixative used was buffered 2.5% glutaraldehyde, administered via the ascending aorta. Tissues were removed and further immersion-fixed with the same fixative. Tissues were embedded in plastic resin and sectioned to 1 micron thickness. Sections were stained (unless otherwise indicated) with a mixture of methylene blue, azure B, and basic fuchsin. Human material was obtained from autopsies.

The slide numbers beginning with b are paraffin-embedded sections obtained from various commercial collections. They are usually 10 microns thick and are stained with hematoxylin and eosin.

Laboratory Exercises

The histology course web page contains a number of laboratory exercises (currently under development) that you can access by clicking on the "Labs" link at the end of this column.

If you would like a guided tour of the slide we have used in this demonstration, click on the "Labs" link below, select "Nervous Tissue and Special Senses," and then scroll down and click on the the slide w84 link.