HISTOLOGY FULL-TEXT

William A Beresford MA, D Phil ©
Professor of Anatomy
Anatomy Department, West Virginia University, Morgantown, USA

Preface

Background - Students expect plentiful coloured illustration in textbooks, and this is essential for learning so visual a subject as Histology. This unillustrated note-style book had a supplementary role when times, time, and prices allowed, but a fourth print edition for the 1990s was not worthwhile. The publishers - Blackwell Science - kindly returned the copyright © to me, where it remains, so that this revised Web version is to be downloaded and printed out for fair personal use, but not for profit.

Print-to-Web adaptation - I saved the 1992 WordPerfect version (thank you, Margaret Beresford) in DOS text, and updated and edited it on a 286, using elementary HTML tags. On a 12-inch monitor screen, the tags give a format very like that of the pocket-sized print edition, which students had earlier found useful.
The aim thereby is not to hamper anyone with a small monitor and a basic Web browser. On a larger screen, the book format is achieved by a 640 X 480 pixels selection. (Some of the figures need a 600 X 800 display to be seen in their entirety.) Also, the style of indentation is varied to make the layout less tedious to the eye.

The order of chapters originally reflected a curriculum of basic histology, and then histology integrated with physiology and biochemistry, taught respectively in two semesters. Hence, there was some duplication of chapter topics. Here, like has been brought together with like, e.g., all neural topics together.

History - I wrote the first edition for the "Lecture Notes on - -" series in 1967-'68, after a few years of teaching medical histology. Then, it was a brief preview-review pocket book, in an era of heavy texts which students had to use. Now the large textbooks, where they still exist, are seldom mentioned or recommended. (The related weighty texts on cellular and molecular biology are premedical fare.)
The result is that what earlier was minimal detail sometimes goes beyond that nowadays presented in class, and expected for testing. However, the difference is minor, and lies mostly in the inclusion of topics and details of protective, clinical, and molecular interest, which should connect with what students engaged in problem-based-learning are coming across.
A sizeable component of histology is the light-microscopical classifications of the nineteenth century. The dated terms and synonyms have been jettisoned to make room for current matters. Electron microscopy has proven to have a place in pathological practice, and still contributes much to the understanding of function, but details that are not significant in either context, e.g., the size of granules in endocrine cells, are excluded.
There is more emphasis on clinical aspects of histology than in the past. The student's experience of basic medical sciences often is of having been dealt a deck of cards - facts and ideas, but without any indication of what plays high or low: as much weight being given to the muscularis layer of the vagina, as to the clinically important transformation zone of the cervix.

Relevance to your histology course? - The effort to separate, structure, and explain should have resulted in a layout that is sometimes helpful, but lets you skip what seems to be totally unfamiliar. An index is not provided, since, if you can see the text on a monitor, you can search by typing in.
Some topics may not be in your histology text, e.g., the 'modern' (1978) zonation of the prostate. The student should use this edition cautiously, paying attention to the particular context of his or her own course and examinations. Still, it is free, and offers another viewpoint.

Death by List - List-management is a basic skill of medicine, but the meal only starts with the grocery list. What is then done with the ingredients decides whether the experience will be enjoyable and memorable, or the patient is properly diagnosed and treated.
One problem is that almost everywhere one can say that a cell does this or that, many of the molecular species used to perform the tasks are known. These materials help define the cell's identity, make function more understandable, and are the basis for disease, e.g., by mutation or autoimmune reaction, but there is just too much of everything - too many types of collagen, cytokines, transcription factors, isoforms of aquaporin, subtypes of T lymphocytes, etc. The brain's expression of 'perplexin' surges.
Some lists have been introduced to this edition, not for memorization, but so that some of the basis for subtyping can be seen, e.g., that proteoglycans are viewed fruitfully as being large or small, aggregated and non-aggregated, and matrix or cellular.
Ideally, the material of medical basic sciences would be in explanatory narrative form. The very format of a book such as this saturates with lists, at the expense of the wealth of intriguing stories possible, although I have tried to keep a narrative running in some of the lists. However, it may not be all bad, since learning and thinking by list prepares one for the many questions on professional exams that use a list format.

Illustrations - With many sources - slides, atlases, textbooks, videodiscs, 35mm transparencies, CD-ROMs, & the Web (see Introduction) - available for the actual visual images of microscopic anatomy, I have used the space here to show the structure of histological knowledge by a condensed, numbered note form, almost unbroken by illustrations.
I thought of replacing the crude figures by 'Photoshop' ones, but these would not allow the book to fit on a I.4 Mb disc, i.e., to stay shirt-pocket-portable. Individual links will eventually be provided to crisp colour figures, as these become freely accessible.
I have started (March, 1999) the introduction of links in the text to Powerpoint slides, e.g., on blood and marrow. Download and use these as you like, with verbal acknowledgement at the time, if projected. [A guide to projection on one make of projector is at Powerpoint.] The Powerpoint slides, as linked, are busy summary ones, designed to be printed out six-to-a-page for review. For projection, they can be copied more than once, and items systematically deleted to provide simpler sequences for more complicated topics.

How does one illustrate the descriptions and ideas of histology? The solution chosen here is to develop links to freely accessible (but copyrighted) Powerpoint diagrams and lists, half of which have now been done (November, 1999). Some are based on lectures for pharmacy students and may not give all the detail expected of medical students, but nevertheless help the beginner.
For those seeking images of actual sections, here are links to some Histology Websites with illustrations : JayDoc HistoWeb
--- Vanderbilt Histology Lessons -- Wisconsin Histology

Molecular histology
The discipline has evolved since the last printed edition in several ways. Cells signal and work by means of special chemicals, and each cell type has a recognizable biochemical identity, significant for the cell's own purposes and potentially in diagnosis and treatment. Mention of key functional and marker chemicals belongs in histology, but here these are mostly introduced unobtrusively at the end of sections. Also, the molecular mechanisms of cellular identity, or how cells come by their distinctive materials, make up a new final chapter.
One way for today's student to prepare for the era of molecular medicine - for diagnosis, and targetting therapy at the cell's controls on particular molecules - is in three early courses: biochemistry for general molecular mechanisms; microbiology for molecular specifics of immunology; and histology for the characteristic molecular species for the full range of cell types, and the mechanisms of how the cells make them. This edition makes a start on the histological side of the endeavour.

Why methods? In Chapter 30 and scattered about, there is more than the usual amount about histological techniques. These approaches have given histology its present substance and form, as molecular thinking will contribute to shaping histology in the future. Both aspects are included in order to aid in comprehending what histology means to medicine. The book looks towards what will probably be useful to medicine, as well as to what has served in the past.

Reliability In a time of specialists and sub-sub-disciplines, is a single-authored book reliable? My longstanding scientific interest is in metaplasia and transdifferentiation, which can involve any cell type and organ, and requires knowing normal phenotypes, and how cells achieve them. Hunting the clinical and basic-science journals for these phenomena also helps to satisfy my curiosity about all the dangling ends from the structures and events of general histology.
Many thanks to all who have sent me reprints.

I would appreciate your calling to my attention by e-mail, fax, or letter:

Servers are more ephemeral than bookshops: URLs for this book are
http://www.geocities.com/Athens/Academy/1575/ a refined, faster version, but needs (May, 2000) to be updated
http://wberesford.hsc.wvu.edu/histol.htm
http://wvnvm.wvnet.edu/~beresfo
Copy it onto a disc, and you only need to come back to see if changes have been made.

William A Beresford, Anatomy Department, School of Medicine, West Virginia University, Morgantown, WV 26506-9128, USA - - e-mail: -- wberesfo@wvu.edu -- wberesfo@hotmail.com -- beresfo@wvnvm.wvnet.edu -- fax: 304-293-8159