2
UNIT 1
Organization of the Body
1
bulging muscles beneath a bodybuilder’s skin, and clinicians
use it to locate appropriate blood vessels in which to feel pulses
and draw blood.
Microscopic anatomy
deals with structures too small to be
seen with the naked eye. For most such studies, exceedingly thin
slices of body tissues are stained and mounted on glass slides
to be examined under the microscope. Subdivisions of micro-
scopic anatomy include
cytology
(si-tol
9
o-je), which considers
the cells of the body, and
histology
(his-tol
9
o-je), the study of
tissues.
Developmental anatomy
traces structural changes that oc-
cur in the body throughout the life span.
Embryology
(em
0
bre-
ol
9
o-je), a subdivision of developmental anatomy, concerns
developmental changes that occur before birth.
Some highly specialized branches of anatomy are used
primarily for medical diagnosis and scientific research. For
example,
pathological anatomy
studies structural changes
caused by disease.
Radiographic anatomy
studies internal
structures as visualized by X-ray images or specialized scan-
ning procedures.
Subjects of interest to anatomists range from easily seen
structures down to the smallest molecule. In
molecular bi-
ology
, for example, the structure of biological molecules
(chemical substances) is investigated. Molecular biology is
actually a separate branch of biology, but it falls under the
anatomy umbrella when we push anatomical studies to the
subcellular level.
One essential tool for studying anatomy is a mastery of ana-
tomical terminology. Others are observation, manipulation,
and, in a living person,
palpation
(feeling organs with your
hands) and
auscultation
(listening to organ sounds with a steth-
oscope). A simple example illustrates how some of these tools
work together in an anatomical study.
Let’s assume that your topic is freely movable joints of the
body. In the laboratory, you will be able to
observe
an animal
joint, noting how its parts fit together. You can work the joint
(
manipulate
it) to determine its range of motion. Using
ana-
tomical terminology
, you can name its parts and describe how
they are related so that other students (and your instructor) will
have no trouble understanding you. Te list of word roots (at
the back of the book) and the glossary will help you with this
special vocabulary.
Although you will make most of your observations with the
naked eye or with the help of a microscope, medical technology
has developed a number of sophisticated tools that can peer into
the body without disrupting it. Read about these exciting medi-
cal imaging techniques in
A Closer Look
on pp. 16–17.
Topics of Physiology
Like anatomy, physiology has many subdivisions. Most of
them consider the operation of specific organ systems. For
example,
renal physiology
concerns kidney function and
urine production.
Neurophysiology
explains the workings
of the nervous system.
Cardiovascular physiology
exam-
ines the operation of the heart and blood vessels. While
the hierarchy of structural organization,
and
homeostasis
—will
unify and form the bedrock for your study of the human body.
Te final section of the chapter deals with the language of
anatomy—terminology that anatomists use to describe the
body or its parts.
An Overview of Anatomy
and Physiology
Define anatomy and physiology and describe their
subdivisions.
Explain the principle of complementarity.
±wo complementary branches of science—anatomy and
physiology—provide the concepts that help us to understand the
human body.
Anatomy
studies the
structure
of body parts and
their relationships to one another. Anatomy has a certain appeal
because it is concrete. Body structures can be seen, felt, and exam-
ined closely. You don’t need to imagine what they look like.
Physiology
concerns the
function
of the body, in other words,
how the body parts work and carry out their life-sustaining ac-
tivities. When all is said and done, physiology is explainable
only in terms of the underlying anatomy.
±o simplify the study of the body, when we refer to body
structures and/or physiological values (body temperature, heart
rate, and the like), we will assume that we are talking about a
healthy young (22-year-old) male weighing about 155 lb (the
reference man
) or a healthy young female weighing about 125 lb
(the
reference woman
).
Topics of Anatomy
Anatomy is a broad field with many subdivisions, each provid-
ing enough information to be a course in itself.
Gross
, or
mac-
roscopic
,
anatomy
is the study of large body structures visible
to the naked eye, such as the heart, lungs, and kidneys. Indeed,
the term
anatomy
(derived from the Greek words meaning “to
cut apart”) relates most closely to gross anatomy because in such
studies preserved animals or their organs are dissected (cut up)
to be examined.
Gross anatomy can be approached in different ways. In
re-
gional anatomy
, all the structures (muscles, bones, blood ves-
sels, nerves, etc.) in a particular region of the body, such as the
abdomen or leg, are examined at the same time.
In
systemic anatomy
(sis-tem
9
ik),* body structure is studied
system by system. For example, when studying the cardiovascu-
lar system, you would examine the heart and the blood vessels
of the entire body.
Another subdivision of gross anatomy is
surface anatomy
,
the study of internal structures as they relate to the overlying
skin surface. You use surface anatomy when you identify the
*For the pronunciation guide rules, see the first page of the glossary in the back of
the book.
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