from The Textbook Letter, July-August 1994
Reviewing a high-school book in human biology
Structure & Function of the Body
1992. 492 pages. ISBN: 0-8016-6403-9. Mosby - Year Book, Inc.,
11830 Westline Industrial Drive, St. Louis, Missouri 63146.
An Excellent Introduction
to a Complicated Subject
Stephanie A. Young
Structure & Function of the Body -- a book that was
originally published in 1960 and has been revised every four
years since then -- does a generally excellent job of presenting
a complicated subject to the novice.
Before discussing the book's strengths and weaknesses, I should
point out some of the limitations of this review and some of my
own biases. I am a practicing pathologist, and I teach medical
students, but I have had no experience in teaching at the
high-school level. I took an anatomy-and-physiology course 25 years
ago, but the textbook that I remember using then had much less
material than Mosby's book does. To cover the material in
Structure & Function of the Body during a one-semester
high-school course would be a very ambitious undertaking.
When I began working on this review, I had seen no earlier
edition of Structure & Function of the Body, and I had no
competing text that might serve for making comparisons, so I
borrowed a copy of a book that is used by a local private high
school: Gerard Tortora's Introduction to the Human Body,
issued by HarperCollins College Publishers. In comparison with
that text, Mosby's is less detailed and is more accessible to a
high-school audience.
The writers of Structure & Function of the Body seem to be
aware of the difficulty in memorizing lots of anatomical detail,
and they have tried to provide interesting commentary along with
their factual information. Sometimes, however, their comments
create problems, as in their discussion of the structure of
nerves. On page 133 the text says that axons in the peripheral
nervous system are sheathed in a myelin-containing neurilemma
(formed by the Schwann cells), that the myelin plays a part in
the regeneration of damaged axons, and that the potential for
regeneration is therefore greater in the peripheral nervous
system than in the brain and the spinal cord, where axons "have
no neurilemma." But the text on the next page introduces the
oligodendroglia and says that "they produce the fatty myelin
sheath that envelops nerve fibers located in the brain and spinal
cord." The apparent discrepancy is never explained. (In the
HarperCollins book, on the other hand, the student finds a clear
-- albeit long and detailed -- discussion of this issue.)
One of the strengths of Mosby's book is the clarity of its
illustrations and of the captions and call-outs that go with
them. The relevant information is all there, the presentation is
usually as straightforward as possible, and the illustrations
invite the student to learn.
There are a few exceptions, however, and two of these occur in
the chapter about nerves. Page 151 has an illustration that
purports to show the circulation of cerebrospinal fluid. This is
a notably difficult concept to depict graphically, and Mosby's
attempt fails. On the next page, a painting of the underside of
the brain has call-outs designating the olfactory tract, the
optic chiasm and the mammillary body, but these structures are
never defined in the text.
Here are some more observations that I made as I looked through
Mosby's book:
Chapter 2, "Cells and Tissues," is well written and well
illustrated. The only serious fault that I find is that the
genetics section needs to be expanded and clarified. The student
who relies on Mosby's treatment of genetics will be hard pressed
to answer the monumental question that appears in the chapter
review: "What is a gene?" (The HarperCollins book has a genetics
section that is superior to Mosby's in both depth and clarity.)
In revising their genetics section, Mosby's writers should be
sure to correct the factual error on page 27: A human zygote gets
23 chromosomes, not "23 pairs of chromosomes," from each parent.
Generally, the photomicrographs seen in chapter 2 are good and
are used effectively, but the one on page 33 could be better: It
supposedly shows lung alveoli, where "[a]bsorption of oxygen into
the blood" occurs, but the capillaries are nowhere in sight. A
better photomicrograph, at the same magnification, would solve
this problem.
Chapter 4, "The Integumentary System and Body Membranes,"
includes a good, illustrated description of the structure of the
skin, and the correlation between structure and function is
emphasized. Chapter 5, "The Skeletal System," is lucid and to
the point, with a fine illustration of the various types of
diarthrotic joint. Chapter 6, "The Muscular System," opens with
a discussion of how muscles work, and then -- perhaps necessarily
-- becomes a series of figures that show musculature and list the
muscles' names. Welcome, students, to the world of anatomy.
Chapter 7, "The Nervous System," has some shortcomings, as I have
noted above, but the chapter as a whole is effective and is
appropriate for high-school students. Where it is weak, the
classroom teacher can introduce supplementary material derived
from the HarperCollins text from another text that has a strong
chapter on neurology.
Chapter 11, "The Circulatory System," is a good discussion of a
difficult topic, and it includes an interesting, illustrated
explanation of EKGs. Chapter 12, "The Lymphatic System and
Immunity," is thorough and makes good use of both
photomicrographs and scanning electron micrographs. I was not
impressed, however, by the sidebar about AIDS (page 261). It is
nothing in comparison with the excellent, three-page presentation
in the HarperCollins text. If students are to get a proper
lesson about AIDS, the teacher will have to look beyond
Structure & Function of the Body for information.
Chapter 13, "The Respiratory System," is sound and includes a
good sidebar on infant respiratory distress syndrome (page 281).
In chapter 16, "The Urinary System," I was particularly impressed
by the diagram of the nephron unit, the text and illustration
that describe the formation of urine, and the discussions of the
artificial kidney, hemodialysis and peritoneal dialysis.
While the sidebar about AIDS is weak, most of the sidebars in
Structure & Function of the Body are commendable. They
help to keep the book interesting by discussing important topics
clearly. The topics range from in-vitro fertilization to
endocrine abnormalities to the Heimlich maneuver.
As a whole, Structure & Function of the Body is an
excellent introductory text, and it can provide solid grounding
for students who may study human anatomy and physiology during
their college work.
A Book That Skimps
on the Why and How
Ben E. Coutant
A textbook of human anatomy and physiology should contain the
essentials: what, where, when, why and how. Mosby's Structure
& Function of the Body does a creditable job with the what,
the where and the when, but it often fails to give proper
explanations of the why and (especially) the how. These are
certainly the most difficult aspects to explore in an
introductory text, but they are also the most important and
interesting ones. Unless sufficient time is spent on them, it is
very hard to capture and maintain the student's attention.
While Structure & Function of the Body provides an
extensive overview of its subject, there are significant
omissions in its coverage of cellular physiology. As a result,
students will have difficulty in achieving an understanding of
how the body really works and can accomplish its many tasks.
Studying biology requires a commitment to learning about cells
and cellular functions, as a requisite for understanding the
workings of an entire organism. Even an introductory text should
attempt to give readers an idea of how individual cells within a
tissue or an organ system contribute to the functioning of that
tissue or system, so students can see connections between events
at the cellular level and effects at the higher levels of
organization.
In Structure & Function of the Body, cell biology is
presented in chapter 2, "Cells and Tissues," but the chapter is
weak. The writers, in their attempt to simplify matters, have
omitted so much that the chapter fails to equip the reader for
comprehending material that will appear later in the book. For
example: Because chapter 2 gives so little space to chemistry,
the student is ill-prepared to understand why the breaking down
of carbohydrates, proteins and fats requires an array of
different enzymes -- a point that the student will encounter in
chapter 14, "The Digestive System." A brief overview of
chemistry and biochemistry is given in Appendix A, at the back of
the book. That material might better have been put into the
book's text, before the discussion of cells and tissues.
A Surprising Defect
In the opening chapter, the discussion of homeostasis (on page
12) contains a major flaw -- surprising because Structure &
Function of the Body is now in its ninth edition.
Homeostasis, the maintaining of a relatively constant internal
environment, is the central concept of physiology, and students
can't understand homeostasis unless they know about the chief
mechanism of homeostatic control: the negative feedback loop.
Mosby's writers cite the system used to maintain homeostasis of
the concentration of carbon dioxide in the blood, yet their
description of that system fails to tell what processes are
involved in sensing the carbon-dioxide concentration and keeping
it within a "normal" range. Further, the accompanying diagram is
titled "Negative Feedback Loop" but fails to show any feedback
path.
A number of other, less serious problems are apparent, some of
them involving the order in which topics are presented. For
instance, the chapter on muscles comes before the chapter about
the nervous system. When students read that muscles respond to
stimuli, it is not at all clear that the stimuli are electrical
and, under normal circumstances, are delivered by nerves.
There are also occasional silly statements, such as the one on
page 313, in the chapter about the digestive system: "Salivary
amylase usually has little time to do its work because so many of
us swallow our food so fast." This appears to be merely a snide
remark, not a scientific statement. It disregards the fact that
amylase, protected within a bolus of food, can continue to work
(for a short time) even after the bolus has entered the acidic
environment of the stomach.
In the same chapter, on page 305, the writers state: "After food
has been in the stomach for about 3 hours, chyme passes through
the pyloric sphincter into the first part of the small
intestine." This erroneously implies that no food leaves the
stomach until some three hours have elapsed. In fact, though,
the stomach normally empties gradually, over a period of two to
three hours after food has been swallowed. The error is minor,
but it can produce a misunderstanding of the digestive process.
The chapter about digestion also suffers from inadequate coverage
of absorption, the major digestive process. The text fails to
present a clear picture of how molecules can move across the
intestinal epithelial layer, whether by active transport or by
passive mechanisms.
In the chapter called "Nutrition and Metabolism," page 321 offers
the statement that "For some reason, energy released from food
molecules cannot be used directly for doing cellular work." This
entirely misses a key point: One major result of metabolic
processes is the conversion of energy into forms that can easily
be used -- or, alternatively, can be stored -- by the organism.
Readable Writing
In terms of its overall structure, the book is well designed.
The text is readable and appears to be appropriate for an
audience of high-school students, though the writers sometimes
use analogies that aren't the most appropriate. For example, on
page 148 they compare the spinal-cord reflex arcs to a telephone
switchboard. This could lead to incorrect perceptions, since
reflex arcs involve synapses that do not change readily. The
connections within a switchboard, on the other hand, change
continually to create alternative pathways for signals to follow.
Each chapter begins with a short outline and a list of
objectives, and each chapter ends with an "outline summary," a
new-word list, a short-answer test, and a set of review
questions. The book would be better if each outline summary were
replaced by a plainly written textual summary that would
synthesize the information presented in the chapter and would
state the functions of the relevant organ systems.
The figures and tables generally seem clear and informative, and
they generally support the text very well. In some instances,
however, a figure is at odds with the text. One such instance is
seen in chapter 13, "The Respiratory System": The text is correct
in stating that bicarbonate is the predominant form of carbon
dioxide in the venous blood, but figure 13-13 implies that
carbaminohemoglobin is the predominant form.
An introductory textbook should not overload students with more
information than they can synthesize and remember, but neither
should it give them so little information that it keeps them from
making logical connections. Structure & Function of the
Body tends to err in the latter direction, at least in its
presentation of physiology.
Stephanie A. Young is a physician, a staff pathologist at Cook
County Hospital (in Chicago), and an assistant professor of
pathology at Rush Medical College (in Chicago).
Ben E. Coutant is an assistant professor in the School of Natural
and Health Sciences at Barry University (Miami Shores, Florida),
where he teaches courses in physiology, anatomy and general
biology.
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