Page 44 - Fundamentals of anatomy physiology

Clinical Note
Autopsies and Cadaver Dissection There is much to
be learned from death. An autopsy is a thorough internal
and external examination of the body after death to deter-
mine the cause of death. Autopsies and cadaver dissections
reveal much about life. Historically, humans have been
fascinated with the human body. Scientists, physicians, and
artists shared this fascination. For example, as early as 304
BCE, Greek anatomist and royal physician Erasistratus and
his physician colleague, Herophilus, dissected human cadav-
ers to learn about internal anatomy. In the second century,
physician Claudius Galen, often recognized as the“father of
anatomy,”was the first to show a connection between patient
symptoms in life and the autopsy observations in death.
In the late 1200s, the University of Bologna was the first in- cytology and histology. Cytology (s.i-TOL-o. -je. ) is the study of
stitution to perform autopsies. In 1632, the Dutch painter,
­Rembrandt created The Anatomy Lesson of Dr. Nicolaes Tulp.
An Italian anatomist, Giovanni M­ orgagni, advanced the field
of anatomical pathology with his 1761 work, On the Seats
and Causes of Diseases. In
1910, Dr. Richard Cabot, an
A­ merican physician, studied
autopsies and learned that
doctors had misdiagnosed
their patients 40 percent of
the time. Today, using cadav-
ers to learn anatomy is com-
monplace. Many students
consider it to be a profound
experience.
component organs. We will introduce the 11 organ systems
in the human body later in the chapter.
Clinical anatomy includes a number of subspecialties im-
portant in clinical practice. Examples include pathological
anatomy (anatomical features that change during illness),
radiographic anatomy (anatomical structures seen using
­specialized imaging techniques), and surgical anatomy
(anatomical landmarks important in surgery).
Developmental anatomy describes the changes in form
that take place between conception and adulthood. The
techniques of developmental anatomists are similar to
those used in gross anatomy and in microscopic anatomy
(discussed next) because developmental anatomy considers
anatomical structures over a broad range of sizes—from
a single cell to an adult human. The most extensive
s­ tructural changes take place during the first two months
of development. The study of these early developmental
processes is called embryology (em-bre. -OL-o. -je. ).
Chapter 1 An Introduction to Anatomy and Physiology 31
Microscopic Anatomy
Microscopic anatomy deals with structures that we cannot see
without magnification. The boundaries of microscopic anat-
1omy are set by the limits of the equipment we use. With a dis-
secting microscope you can see tissue structure. With a light
microscope, you can see basic details of cell structure. And
with an electron microscope, you can see individual molecules
that are only a few nanometers (billionths of a meter) across.
Microscopic anatomy includes two major subdivisions:
the internal structure of individual cells, the simplest units of
life. Cells are made up of chemical substances in various combi-
nations, and our lives depend on the chemical processes taking
place in the trillions of cells in the body. For this reason, we
consider basic chemistry (Chapter 2) before we examine cell
structure (Chapter 3). Histology (his-TOL-o. -je. ) is the exami-
nation of tissues—groups of specialized cells and cell p­ roducts
that work together to perform specific functions (Chapter 4).
Tissues combine to form organs, such as the heart, kidney, liver,
or brain, each with specific functions. Many organs are easy to
examine without a microscope, so at the organ level we cross the
boundary from microscopic anatomy to gross anatomy. As we
proceed through the text, we will consider details at all levels,
from microscopic to macroscopic (Spotlight Figure 1-1).
Physiology
As noted earlier, physiology is the study of the function of
anatomical structures. Human physiology is the study of the
functions, or workings, of the human body. These functions are
complex processes and much more difficult to examine than
most anatomical structures. As a result, there are even more
specialties in physiology than in anatomy. Examples include:
Cell physiology, the study of the functions of cells, is the
cornerstone of human physiology. Cell physiology looks
at events involving the atoms and molecules important to
life. It includes both chemical processes within cells and
chemical interactions among cells.
Organ physiology is the study of the function of specific
organs. An example is cardiac physiology, the study of heart
function—how the heart works.
Systemic physiology includes all aspects of the functioning of
specific organ systems. Cardiovascular physiology, respira-
tory physiology, and reproductive physiology are examples.
Pathological physiology is the study of the effects of diseases
on organ functions or system functions. Modern medicine
depends on an understanding of both normal physiology
and pathological physiology.
Physicians normally use a combination of anatomical,
physiological, chemical, and psychological information when