Histology Guide

virtual histology laboratory



This web site and corresponding atlas represents many years of work by T. Clark Brelje and Robert L. Sorenson. Many hours have been spent finding the best specimens, processing images, producing the atlas, and developing this web site.

T. Clark Brelje

T. Clark Brelje, Ph.D. has taught histology laboratories for medical students for over 20 years.

Robert L. Sorenson, Ph.D.

Robert L. Sorenson has taught histology for medical students for over 40 years.

Histology Guide

Histology is the study of cells, tissues and organs as seen through a microscope.

Histology Guide teaches the visual art of recognizing the structure of cells and tissues and understanding how this is determined by their function. Rather than reproducing information found in a histology textbook, a user is shown how to apply this knowledge to interpret cells and tissues as viewed through a microscope.

Because of the high cost of purchasing (and maintaining) microscopes and preparing (or purchasing) slide collections, histology is often taught today without laboratories. A histology atlas is frequently used as replacement. This is unfortunate because no matter how good the few images in a textbook or histology atlas are, they cannot replace the experience of viewing a specimen through a microscope.

Histology Guide solves this problem by recreating the look and feel of a microscope in an intuitive, browser-based interface.

This approach provides a more engaging learning experience and sense of scale, proportion and context that is not possible with a traditional histology textbook or atlas.

The Atlas of Human Histology: A Guide to Microscopic Structure of Cells, Tissues and Organs by Robert L. Sorenson provides a print version of the core slides from this web site. Individual slides are presented as a series of images of increasing magnification to help convey a sense of scale and proportion. This atlas allows each student to have an easily accessible, printed summary of the essential slides from this web site.

This web site is intended to be used with - not replace - a good histology textbook.

Slide Box

Most of the microscopic slides in this atlas came from a collections used by medical, dental and undergraduate students of histology at the University of Minnesota (Minneapolis, MN). Most were prepared in the 1950's by Anna-Mary Carpenter, M.D., Ph.D., during her tenure as Professor in the Department of Anatomy (University of Minnesota). These slides form the basis for the Atlas of Human Histology: A Guide to Microscopic Anatomy Slides. The virtual slide box also contains many additional slides that complement and extend this core slide collection. The virtual slide box contains a more than 225 digitized slides representing 1.8 TB of images.

A large number of slides were examined to find the best example of each specimen. Each slide, in its entirety, was digitized with a high resolution 40x lens to generate virtual microscope slides. In some cases, such as blood cells and bone marrow, smaller regions have been digitized with an oil-immersion 60x lens to generate the highest resolution images available with traditional light microscopy.

Every effort has been made to faithfully reproduce these specimens as virtual slides. Each image has had its contrast, color balance, and detail (by careful use of sharpening) adjusted to provide the best representation of these slides. In some cases, the images were further processed to remove debris and artifacts. Nonetheless, a full appreciation of histological structure can only be obtained by examining tissue sections with a microscope.

Electron Microscopy

We are fortunate to have permission to use electron micrographs from the personal archives of Stanley L. Erlandsen. Although some were published in the Color Atlas of Histology by Stanley L. Erlandsen and Jean E. Magney (Moseby-Year Book, Inc., 1992), he collected many more images during his years of teaching histology. This web site presents a broader selection of these remarkable micrographs.

Each electron micrograph has been digitized at high resolution from the best available source (either a negative, 35 mm slide, or photographic print). The resolution of individual images varies because of improvements in electron microscopes and the methods used to archive images over the last 50 years. Each image has had its contrast and detail (by careful use of sharpening) adjusted to provide the best representation of the source material. As with the virtual slides, the large size of these images allow both large and small structures to be examined in most images.

To aid the interpretation of these grayscale images, many have been "hand-colored" to highlight structures in these electron micrographs. To prevent reliance on these colored images, the user interface allows switching between the original grayscale and colored images at all times. These colored images, rather than the extensive use of labels, are more effective in helping students develop the ability to recognize the structure of cells and tissues in traditional, grayscale electron micrographs.


The illustrations were either drawn by Jean E. Magney during her years of teaching histology or were prepared by us specifically for this web site.