s educators, clinically trained individuals, and peren-
nial students, we are continually challenged by the
learning mind. What works best to help students ap-
ply new information to the world they personally understand?
Our clinical backgrounds have served our teaching and writing
purposes well. Perhaps even more important, our clinical expe-
rience has allowed us to see our presentations through our stu-
dents’ eyes and from the vantage points of their career interests.
For this edition, as for those preceding it, feedback from
student and instructor reviews indicated areas of the text that
needed to be revised for clarity, timeliness, and just plain reduc-
tion of verbal meatiness. Overall, feedback was positive, veri-
fying that our approach is eﬀective: Explaining fundamental
principles and unifying themes ﬁrst creates a strong base for
what comes later. Backing these explanations up with comfort-
able analogies and familiar examples enhances students’ under-
standing of the workings of the human body.
Tree integrating themes that organized, uniﬁed, and set the
tone of the ﬁrst edition of this text continue to be valid and are
retained in this edition. Tese themes are:
Interrelationships of body organ systems.
Te fact that nearly
all regulatory mechanisms require interaction of several organ
systems is continually emphasized. For example, Chapter 25,
which deals with the structure and function of the urinary sys-
tem, discusses the vital importance of the kidneys not only in
maintaining adequate blood volume to ensure normal blood
circulation, but also in continually adjusting the chemical
composition of blood so that all body cells remain healthy.
feature is the culmination of
this approach and should help students think of the body as a
dynamic community of interdependent parts rather than as a
number of isolated structural units.
Te normal and most desirable condition of body
functioning is homeostasis. Its loss or destruction always leads
to some type of pathology—temporary or permanent. Patho-
logical conditions are integrated with the text to clarify and illu-
minate normal functioning, not as an end in and of themselves.
For example, Chapter 19, which deals with the structure and
function of blood vessels, explains how the ability of healthy ar-
teries to expand and recoil ensures continuous blood ﬂow and
proper circulation. Te chapter goes on to discuss the eﬀects on
homeostasis when arteries lose their elasticity: high blood pres-
sure and all of its attendant problems. Tese homeostatic im-
balances are indicated visually by a pink symbol with a fulcrum:
Whenever students see the imbalance symbol in text, the con-
cept of disease as a loss of homeostasis is reinforced. Every Ho-
meostatic Imbalance section has a new, related clinical question
that is assignable in MasteringA&P. Tese new clinical ques-
tions help strengthen students’ understanding of how the body
works to stay in balance.
Complementarity of structure and function.
Students are en-
couraged to understand the structure of an organ, a tissue, or a
cell as a prerequisite to comprehending its function. Concepts
of physiology are explained and related to structural character-
istics that promote or allow the various functions to occur. For
example, the lungs can act as a gas exchange site because the
walls of their air sacs present an incredibly thin barrier between
blood and air.
NEW TO THE NINTH EDITION
With every edition, our goal is powerful but simple—to make
anatomy and physiology as engaging, accurate, and relevant
as possible for both instructors and students. Te Ninth Edi-
tion represents a monumental revision, with changes to the text
and art presentation that build upon the hallmark strengths of
the previous eight editions. Te changes to the Ninth Edition
are all driven by the needs of today’s students, as we seek to
make the learning of key concepts in A&P as easy as possible for
them. Key concepts are important because of the overwhelming
amount of material in this course. Mastering this material gives