About the Book

The intended audience for this book consists of students and other intelligent readers who have little or no background in science, particularly in biology. These individuals may want to learn about the biology of aging in humans for personal reasons or as part of their preparation for careers that involve working with older people, such as health care, sociology, social work, recreation, education, and psychology. These readers may also need to know about diseases that commonly affect the elderly. For students, this book will serve as a text in courses that emphasize or are devoted entirely to the biology of aging in humans. This book can enable students and other readers to do the following:

1. Demonstrate knowledge of demographic information pertaining to the elderly in the United States and an understanding of the significance of this information.
2. Name and describe factors that are believed to cause or influence the process of aging.
3. List and describe theories of aging.
4. Define and describe the concept of homeostasis and explain its importance and how it is maintained.
5. Describe the normal structure, functioning, and contributions to healthy survival for each body system in young adults.
6. Describe age changes in each body system and the interactions among these systems in older adults.
7. Describe certain abnormal changes in body systems and the interactions among these systems in older adults.
8. Describe interactions among biological, psychological, social, and economic factors in older adults.
9. Relate and use this knowledge in their personal and professional lives.

The concept of homeostasis and the effects of aging on the ability to maintain homeostasis are the unifying themes which tie together all the sections of the book. Descriptions of changes in reserve capacity and methods of preventing abnormal changes and disease also permeate the text.

Chapter 1 includes background material about why aging should be studied, homeostasis, types of aging, methods of study, differences between age changes and other age-related changes, heterogeneity, and longevity.

Chapter 2 describes structure and functioning of cells and intercellular materials. This information provides the foundation for a discussion of theories of aging and for the later chapters. Most of the information about age changes and age-related abnormal changes at the cellular and molecular levels is incorporated into the discussions of body systems in Chapters 3 through 15, where such information is related to structural and functional alterations that affect homeostasis and the quality of life.

Except for Chapter 11 (Diet and Nutrition) and Chapter 16 (Into the Future), each of the remaining chapters discusses one body system. The organization within these chapters is consistent. Each begins with a discussion of the ways in which the system or aspect of the body being discussed contributes to homeostasis and therefore to the healthy survival of the individual. This is followed by a section on anatomy and physiology which contains information pertinent to the subsequent sections of the chapter. Students who are well versed in these topics may be able to move quickly to the second section of each chapter.

The second section of the chapter describes changes in structure and function that occur with aging and alter the ability to maintain homeostasis or a high quality of life. The third part of each chapter presents information about abnormal changes and diseases that commonly occur in the elderly and are usually considered important. This section includes information about causes, development, signs and symptoms, and consequences. Much information about preventive measures is included, and some treatment strategies are mentioned. In chapters where many different parts of a system and lengthy discussions about one part of a system are presented, the information about age changes, abnormal changes, and diseases in each part follows the material on the anatomy and physiology of that part. Interspersed within each chapter are references to interrelationships between age changes, abnormal changes, diseases, and psychological, sociological, and economic factors involving the elderly.

Additional features of this book that will enable students and other readers to achieve the objectives enumerated above include the following:

1. The online Learning Objectives, Outline, and Lecture Notes are available for each chapter .
2. The level and style of writing are friendly and readable.
3. The use of technical terms and scientific jargon are minimized, and terms that are included are clearly defined in the text and in the glossary.
4. The discussions have enough depth and breadth to be complete without being overwhelming.
5. The organization of topics allows instructors to delete selected sections when course time is limited.
6. The text includes illustrations and tables designed to clarify the narrative.
7. Age changes are distinguished from abnormal and disease changes wherever such distinctions have been discovered. Places where these distinctions have not yet been elucidated are clearly indicated.

This eBook edition provides an updated version of the previous print editions, which received overwhelmingly positive responses by reviewers, colleagues, and students. It also addresses as best I can the shortcomings mentioned by these same audiences. Still, I want to remain true to the overall purposes of the book, which are stated in the print editions' preface and encapsulated in the title. Here is how I pursue these goals.

First, I compare the book's content with current literature. Content that is reaffirmed remains. Outdated content is updated or eliminated. Beyond this, the eBook edition contains all the content from the previous edition because I received very few suggestions to shorten or omit content.

Then I expand the sections that seemed most wanting. These include demographics; methods of studying aging; reserve capacity; differences between aging, disease, and environmental insults; genetics of human aging; basic chemistry; cell division; theories of aging; cognitive functions (i.e., memory, intelligence); Alzheimer's disease; photoaging of the skin and treatments; antioxidant supplements; dietary supplements; hormone supplements; caloric restriction; immune system imbalance; use of theories of aging within chapters; and incidences of diseases. I use theories of aging in explaining age changes in body systems (e.g., atherosclerosis, dementia, muscle, eyes, glaucoma, nutrition, diabetes, immune dysregulation).

I include sections on: quality of life; spirituality; free radicals and antioxidants; evolutionary theories; telomeres and telomerase; Hayflick limit; replicative senescence; Werner's syndrome; progeroid syndromes; chronic heat exposure; heat shock protein; elastin peptides; homocysteine; smoking; dementia with Lewy bodies; biorhythms and circadian rhythms; types of muscle cells; driving motor vehicles; Dietary Reference Intakes (DRIs); Viagra; melatonin supplements; DHEA; Grave's disease; insulin-like growth factors; future problems, challenges, and opportunities; and world population growth.

Finally, I created new illustrations on: demographics; body reserve capacity; molecules; cell membrane; chromosome and telomere; cytoskeleton; cell cycle; lung capacities; primary and secondary immune responses; effects from altering longevities; and world population growth. I added links to supplementary illustrations, videos, updated information, and online articles.