3
CHAPTER ONE
Introduction to Human Anatomy and Physiology
1.1
INTRODUCTION
Our understanding of the human body has a long and
interesting history
(fig. 1.1)
. Our earliest ancestors must
have been curious about how their bodies worked. At F
rst
their interests most likely concerned injuries and illnesses,
because healthy bodies demand little attention from their
owners. Primitive people suffered aches and pains, injured
themselves, bled, broke bones, developed diseases, and con-
tracted infections.
The change from a hunter-gatherer to an agricultural
lifestyle, which occurred from 6,000 to 10,000 years ago in
various parts of the world, altered the spectrum of human
illnesses. Before agriculture, isolated bands of peoples had
little contact with each other, and so infectious diseases did
not spread easily, as they do today with our global connec-
tions. These ancient peoples ate wild plants that provided
chemicals that combated some parasitic infections. A man
who died in the Austrian/Italian Alps 5,300 years ago and
whose body was found frozen was carrying mushrooms that
had antibiotic activity.
With agriculture came exposure to pinworms, tape-
worms, and hookworms in excrement used as fertil-
izer, and less reliance on the natural drugs in wild plants.
Urbanization brought more infectious disease as well as mal-
nutrition, as people became sedentary and altered their diets.
Evidence from preserved bones and teeth chronicle these
changes. Tooth decay, for example, affected 3% of samples
from hunter-gatherers, but 8.7% from farmers, and 17% of
samples from city residents. Preserved bones from children
reflect increasing malnutrition as people moved from the
grasslands to farms to cities. When a child starves or suf-
fers from severe infection, the ends of the long bones stop
growing. When health returns, growth resumes, but leaves
behind telltale areas of dense bone.
The rise of medical science paralleled human prehistory
and history. At F rst, healers relied heavily on superstitions
and notions about magic. However, as they tried to help
the sick, these early medical workers began to discover use-
ful ways of examining and treating the human body. They
observed the effects of injuries, noticed how wounds healed,
and examined dead bodies to determine the causes of death.
They also found that certain herbs and potions could treat
coughs, headaches, and other common problems. These
long-ago physicians began to wonder how these substances,
the forerunners of modern drugs, affected body functions.
People began asking more questions and seeking
answers, setting the stage for the development of modern
medical science. Techniques for making accurate obser-
vations and performing careful experiments evolved, and
knowledge of the human body expanded rapidly.
This new knowledge of the structure and function of
the human body required a new, specialized language.
Early medical providers devised many terms to name body
parts, describe their locations, and explain their functions.
These terms, most of which originated from Greek and Latin,
formed the basis for the language of anatomy and physiol-
ogy. (A list of some of the modern medical and applied sci-
ences appears on pages 24–25.)
Although study of corpses was forbidden in Europe dur-
ing the Middle Ages, dissection of dead bodies became a key
part of medical education in the twentieth century. Today,
cadaver dissection remains an important method to learn
how the body functions and malfunctions, and autopsies are
vividly depicted on television crime dramas. However, the
traditional gross anatomy course in medical schools is some-
times supplemented with learning from body parts already
dissected by instructors (in contrast to students doing this)
as well as with computerized scans of cadavers, such as the
Visible Human Project from the National Library of Medicine
and Anatomy and Physiology Revealed available with this
textbook.
PRACTICE
1
What factors probably stimulated an early interest in the human
body?
2
How did human health change as lifestyle changed?
3
What types of activities helped promote the development of
modern medical science?
FIGURE 1.1
The study of the human body has a long history, as this
illustration from the second book of
De Humani Corporis Fabrica
by
Andreas Vesalius, issued in 1543, indicates. Note the similarity to the
anatomical position (described on page 20).
previous page 33 David Shier Hole's Human Anatomy and Physiology 2010 read online next page 35 David Shier Hole's Human Anatomy and Physiology 2010 read online Home Toggle text on/off