Introduction to Human Anatomy and Physiology
composed of chemicals
. Clinical Application 1.1
describes two technologies used to visualize body parts
based on body chemistry.
Chapters 2–6 discuss these levels of organization in more
detail. Chapter 2 describes the atomic and molecular lev-
els; chapter 3 presents organelles and cellular structures and
functions; chapter 4 explores cellular metabolism; chapter 5
describes tissues; and chapter 6 presents the skin and its acces-
sory organs as an example of an organ system. In the remain-
ing chapters, the structures and functions of each of the other
organ systems are described in detail.
lists the lev-
els of organization and some corresponding illustrations in
summarizes the organ systems, the
major organs that comprise them, and their major functions in
the order presented in this book. They are discussed in more
detail later in this chapter (pages 14–18).
How does the human body illustrate levels of organization?
What is an organism?
How do body parts at diF
erent levels of organization vary in
The human body
is composed of parts within parts,
with increasing complexity.
Levels of Organization
Electrons, protons, neutrons
Hydrogen atom, lithium atom
Water molecule, glucose molecule
Protein molecule, DNA molecule
Mitochondrion, Golgi apparatus,
Muscle cell, nerve cell
Simple squamous epithelium, loose
Skin, femur, heart, kidney
Integumentary system, skeletal
system, digestive system