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CHAPTER
1
The Human Body: An Orientation
Objectives
An Overview of Anatomy and Physiology
1. Define anatomy and physiology and describe their subdivisions.
Levels of Structural Organization
3. Name the different levels of structural organization that make up the human body, and
explain their relationships.
Maintaining Life
5. List the functional characteristics necessary to maintain life in humans.
Homeostasis
7. Define homeostasis and explain its significance.
The Language of Anatomy
10. Describe the anatomical position.
11. Use correct anatomical terms to describe body directions, regions, and body planes or
sections.
Suggested Lecture Outline
I. An Overview of Anatomy and Physiology (pp. 2–3)
A. Anatomy is the study of the structure of body parts and their relationships to each other,
and physiology is the study of the function of body parts (p. 2).
B. Topics of Anatomy (p. 2)
1. Gross (macroscopic) anatomy is the study of structures large enough to be seen with
the naked eye.
a. Regional anatomy is the study of all body structures in a given body region.
2. Microscopic anatomy is the study of structures that are too small to be seen with the
naked eye.
a. Cytology is the study of individual cells.
3. Developmental anatomy is the study of the change in body structures over the course
of a lifetime; embryology focuses on development that occurs before birth.
4. Specialized Branches of Anatomy
a. Pathological anatomy is the study of structural changes associated with disease.
5. Essential tools for studying anatomy are the mastery of medical terminology and the
development of keen observational skills.
C. Topics of Physiology (pp. 2–3)
1. Physiology has several topics, most of which consider the function of specific organ
D. Complementarity of Structure and Function (p. 3)
1. The principle of complementarity of structure and function states that function is
dependent on structure, and that the form of a structure relates to its function.
II. Levels of Structural Organization (pp. 3–4; Fig. 1.1)
A. The chemical level is the simplest level of organization (p. 3; Fig. 1.1).
1. Atoms, tiny building blocks of matter, combine to form molecules.
B. The cellular level is the smallest unit of life, and varies widely in size and shape accord-
ing to the cells’ function.
F. The organismal level is the total of all structures working together to promote life.
III. Maintaining Life (pp. 4–8; Figs. 1.2–1.3)
A. Necessary Life Functions (pp. 4–8; Fig. 1.2)
1. Maintaining boundaries allows an organism to maintain separate internal and external
environments, or separate internal chemical environments.
2. Movement allows the organism to travel through the environment, and allows
transport of molecules within the organism.
B. Survival Needs (p. 8)
1. Nutrients are consumed chemical substances that are used for energy and cell building.
2. Oxygen is required by the chemical reactions that release energy from foods.
IV. Homeostasis (pp. 8–11; Figs. 1.4–1.6)
A. Homeostasis is the ability of the body to maintain a relatively constant internal environ-
ment, regardless of environmental changes (pp. 8–9).
B. Homeostatic Control (pp. 9–11; Figs. 1.4–1.6)
1. Components
a. Variable: the regulated factor or event.
2. Negative Feedback Mechanisms
a. Most homeostatic control mechanisms are negative feedback mechanisms.
c. Both the nervous system and the endocrine system are important to the maintenance
of homeostasis.
3. Positive Feedback Mechanisms
a. A positive feedback mechanism causes the variable to change in the same direction
as the original change, resulting in a greater deviation from the set point.
4. Homeostatic imbalance often results in disease.
V. The Language of Anatomy (pp. 11–20 ; Figs. 1.7–1.12; Table 1.1)
A. Anatomical Position and Directional Terms (pp. 11–13; Table 1.1)
1. Anatomical position is a position in which the body is erect, palms face forward, and
thumbs point away from the body.
2. Directional terms are used to explain exactly where one body part is in relation to
another.
B. Regional Terms (p. 13; Fig. 1.7)
1. There are two fundamental divisions of the body.
a. The axial region includes the head, neck, and trunk.
2. Regional terms designate specific areas within the axial and appendicular divisions.
C. Anatomical variability does exist within internal organs, although well over 90% of all
structures in the human body match textbook descriptions (p. 14).
D. Body Planes and Sections (p. 14; Fig. 1.8)
1. Body planes are flat surfaces that lie at right angles to each other.
a. Sagittal plane: a vertical plane that separates the body into right and left parts.
i. Median, or midsagittal plane: lies exactly along the body’s midline.
2. Sections are cuts made along specific planes.
a. Transverse section, or cross section, is a cut made along the transverse plane.
b. Oblique sections are cuts made at angles between the horizontal and vertical planes.
E. Body Cavities and Membranes (pp. 14–20; Figs. 1.9–1.12)
2. The dorsal body cavity is the space that houses the central nervous system, and has
two subdivisions: the cranial cavity and the vertebral cavity.
3. The ventral body cavity is anterior to and larger than the dorsal cavity and has two
main subdivisions: the thoracic cavity and the abdominopelvic cavity.
a. The thoracic cavity is a superior division of the ventral cavity that is further subdi-
vided into the lateral pleural cavities that surround the lungs.
4. The ventral body cavity houses the body organs, or viscera.
5. Membranes in the Ventral Body Cavity
a. Serous membranes, or serosae, cover the inner walls of the ventral cavity and the
outer surfaces of organs.
6. Abdominopelvic Regions and Quadrants
a. There are nine abdominopelvic regions used primarily by anatomists.
7. Other Body Cavities
a. Oral and digestive cavities are continuous cavities that extend from the mouth
through the digestive system to the anus.
Cross References
Additional information on topics covered in Chapter 1 can be found in the chapters listed below.
1. Chapter 2: Basic chemical and physical principles
4. Chapter 16: Hormonal control as an example of feedback regulation
Lecture Hints
1. The Internet provides a wealth of information on human anatomy and physiology.
Throughout the semester, encourage students to spend some time looking at college
2. In order to illustrate the principle of complementarity of structure and function, ask the
students to consider the relatively similar structure of the human arm and a bird wing.
3. Many students have a very poor concept of the dynamics of the human body and how it
functions in the environment. Try to stress throughout this chapter the adaptive nature of
the body and the interrelationship between environmental variables and system response.
4. The body organ systems are actually an artificial grouping of structures that work toward
a common goal. Stress the interrelationship between organs and systems that make the
body “work” as an entire unit.
7. Students often equate the term negative in feedback systems to something disruptive.
This misunderstanding is compounded by the term positive also used in feedback
systems. Stress the differences and give an example; for example, describe how a
thermostat controls house temperature.
8. To illustrate the different degrees of protection in the dorsal and ventral cavities, ask the
questions:
Activities/Demonstrations
1. Audiovisual materials are listed in the Multimedia in the Classroom and Lab section of
this Instructor Guide (p. 387).
4. Have students identify body regions on themselves or a lab partner. Stress the usage of
directional terms in describing their positions relative to each other.
5. Arrange for the class to attend an autopsy (after the material in Chapter 1 has been
covered).
Critical Thinking/Discussion Topics
1. Discuss how our intercellular environment can be described as the “sea within us.”
2. List several embryonic features that form early in the developmental stages but are “lost”
or converted to entirely new structures, such as our “tail” (coccyx).
Library Research Topics
1. Research the historical development of anatomy and physiology.
2. Review the current definitions of death and life.
List of Figures and Tables
All of the figures in the main text are available in JPEG format, PPT, and labeled & unlabeled
format on the Instructor Resource DVD. All of the figures and tables will also be available in
Transparency Acetate format. For more information, go to www.pearsonhighered.com/educator.
Figure 1.1 Levels of structural organization.
Figure 1.5 Body temperature is regulated by a negative feedback mechanism.
Figure 1.6 A positive feedback mechanism regulates formation of a platelet plug.
Figure 1.7 Regional terms used to designate specific body areas.
Figure 1.8 Planes of the body with corresponding magnetic resonance imaging
(MRI) scans.
Answers to End-of-Chapter Questions
Multiple-Choice and Matching Question answers appear in Appendix H of the main text.
Short Answer Essay Questions
11. Function (physiology) reflects structure, structure will determine and/or influence
function. (p. 3)
12. See Figure 1.3, which provides a summary of all the organ systems of the body.
14. It is the ability to maintain internal conditions within a narrow set of limits, even in the
face of continuous change in the outside world. (pp. 9–10)
16. The anatomical position requires the body being erect, the arms hanging at the sides, the
palms forward, the thumbs pointing away from the body, and the feet flat to the ground.
17. A plane refers to an imaginary line, and a section refers to a cut along that imaginary line.
(p. 14)
18. a. arm—brachial
b. thigh—femoral
c. chest—thoracic
Critical Thinking and Clinical Application Questions
1. a. Parietal and/or visceral pleural membranes.
b. The membranes allow the organs to slide easily across the cavity walls and one
2. a. anterior aspect of elbow
b. took off his shirt
c. buttock (p. 13)
3. Of the procedures listed, MRI would be the best choice because dense structures (e.g.,
the skull) do not impair the view with this technique, and it is best at producing a high-
4. This is an example of a negative feedback mechanism. The initial stimulus is the drop in
5. The carpal region is found at the wrist. (p. 13)
Suggested Readings
Bagaria, V., et al. “Use of Rapid Prototyping and Three-Dimensional Reconstruction Model-
ing in the Management of Complex Fractures.” European Journal of Radiology 80 (3)
(Dec. 2011): 814–820.
Hazen, Robert. “What Is Life?” New Scientist 192 (Nov. 2006): 46–51.
Lester, David S., and James L. Olds. “Biomedical Imaging: 2001 and Beyond.” The Anatomi-
cal Record 265 (2001): 35–36.
