Health Studies

An Introduction

Jennie Naidoo, Jane Wills

• Publisher: Bloomsbury Academic
• Year: 2015
• Print ISBN:
  9781137348678
• eBook ISBN:
  9781350311220
• Edition: 3
• Topic: Medicine
• Subtopic: Nursing

This new edition of a very successful textbook provides an up-to-date, broad and authoritative introduction to studying health. With chapters including biology, epidemiology, anthropology, politics and psychology, it is the only book to explore all the major disciplines and highlight how they can contribute to our understanding of health in one single volume. Comprehensive, accessible and written by leading experts in the different fields, this is the introductory text for all students of health studies. New to this Edition:
- A whole new chapter on geography and health: it explores the relationship between people's health and the natural and built environments
- New example features in every chapter which apply each discipline to contemporary health issues -from the increase in obesity to the impact of changing social and welfare policies- along with bullet points that highlight the latest research in the field
- A complete update on both the design and layout ensures an even more navigable and enjoyable read for current students, along with new contributions from experts from across the globe

chapter 1

Human biology and health

S.H. CEDAR

Overview

Introduction

Part 1 The contribution of biology to health studies

Cell theory

Homeostasis

Genes and genetics

Ill health and disease

Part 2 Theoretical and research approaches

Induction

Deduction

Proof and falsification

Experimentation

Techniques

Case study Biological explanations for obesity

Summary

Questions for further discussion

Further reading and resources

References

Learning outcomes

This chapter will enable readers to:

• Gain an appreciation of the scope of human biology, the framework of homeostasis and health, and the use of biology to examine ill health and disease
• Be aware of the scientific methods used by biologists, bioscientists and biomedical scientists
• Understand how biology can contribute to the analysis of physical aspects of human health

Overview

Natural sciences seek to explain the natural world, while social sciences seek to explain human societies, culture and belief. This book is largely made up of social science disciplines, but because its focus is health, the natural sciences and, in particular, biology, offer a fundamental perspective. Natural science limits what it investigates to the natural phenomena in the universe. It does not investigate human feelings, morals or beliefs as cultural phenomena. Biology contributes to the study of health by providing knowledge of the body’s functions and how these are interlinked. These issues are illustrated later in the chapter using a biological analysis of food, nutrition and obesity. Human biology concerns how the body functions in terms of its cells, tissues and body systems. This chapter will briefly explain some biological theories such as the function of cells in all organisms; how each body system contributes to the maintenance of a constant internal environment (homeostasis) for its cells; and gene theory. Most importantly, biology is a science and science is an experimental, evidence-based pursuit. The discipline of science dates back about 2,500 years to ancient Greece (Wolpert, 2000). It is derived from the Greek episteme, which distinguishes science as knowing not only that something is so, an act of experience, but also why it is so, an act of the ‘knowledge of first causes’, as Aristotle would say in his Metaphysics (Finley, 1963). It uses scientific methods variously described as induction, deduction, falsification and hypothetico-deduction. This chapter will explain the principles and processes of the scientific method.

Introduction

Biology is the science of life (from the Greek words bios, life, and logos, reasoned account). It is the study of living organisms, what they are made of and how they function, how they interact with each other and with the environment, the effect they have on the environment and the environment has on them. In biology, humans are seen as just one type of organism, one species or race. Species are defined as of one kind when they can breed together and have viable offspring. As all humans can do this, all humans, biologically, are one species or race. In this chapter, while biology applies to all living organisms, it is the human species, Homo sapiens, that interests students of health.

Biology is the study of living organisms and their environment. It can be divided into subcategories, such as human biology, immunology, genetics, anatomy and physiology. Anatomy is the study of the structure of organisms, what they look like, their form. It is used in evolutionary biology to see similarities and differences between species and in medicine to see normal, healthy forms from abnormal ones. It can also be used to look at the structures of organs within a body, such as the structure of the heart, lungs or blood vessels. Physiology, meaning the study (logos) of nature or origin, is the study of the living processes within an organism, such as breathing, moving, eating, eliminating, growing, reproducing and dying. In fact, these processes are often used as the activities of daily living, which are used to access the ability of a person to maintain an independent, healthy, age-appropriate lifestyle (Cedar, 2012). It includes how the entire organism as well as organs, cells and molecules maintain the system. These physiological processes are carried out by anatomical structures and thus there is a link between the form of an organ and its function. Biology encompasses anatomy and physiology, as well as the subdivisions mentioned previously, and will be used here as the generic study in which human biology and health sit.

Science can be divided into ‘pure’ (also called ‘basic’) and ‘applied’. Pure or basic science is the description, explanation and understanding of phenomena and this understanding can be applied to many areas. From this, you can understand that science intends to be universal, applicable everywhere. Applied science is the application of pure or basic scientific principles to meet a specific, recognized need, for example biomedical science applies scientific principles and methods to human illness in the hope of treating a disease. In addition to all the specialized applied fields within biology, many applications of biology such as medicine involve many additional specialized subdisciplines. The remit of biology, however, is not to cure human disease, but to understand how living organisms work, their physiology and what life is. Science aims to be politically neutral, objective and reproducible. It also, like philosophy from which it derives, aims to be universal in its findings rather than culturally particular. However, the application of science by society for dangerous or deadly ends, such as the development of the nuclear bomb or indeed genetic engineering, cannot be ignored.

Because the physiology of health relies on biological underpinnings, students of health studies will need to understand the biology and its associated academic disciplines if they want to work later in nutrition or sports or exercise science.

Part 1 The contribution of biology to health studies

example 1.1

Application of biology to contemporary health issues

• To understand the functions of the body
• How the body adapts to its environment such as cold or lack of energy
• The resiliency factors that buffer individuals from changes in their environment
• How health shapes the individual life course and vice versa
• The manifestations of disease and its pathogenesis
• How genetic understanding can improve fertility and protection against disease

Biology is a scientific discipline that contributes to our understanding of the bodily processes and functions that keep us alive in various states of health. The case study example of obesity illustrates how a biological framework can identify the cause of a health problem and contribute to its management or cure. Similarly, a knowledge of the molecular composition of foods and their biochemical behaviour enables effective nutrition for the needs of the person. The distinction between the biological science and its medical application is therefore an important one. Biology studies how a body functions; it is not of itself clinical. Biology informs medicine but has a separate identity. Medicine without an underlying understanding of biology would rely on belief and myth rather than scientific evidence. This chapter demonstrates the use of a biological framework in the analysis of physical and chemical aspects of health. Biology is interested in the normal, functioning organism, but it is often when an organism is not functioning that new ways of seeing how it normally functions are revealed. When an organism is not functioning normally, it is said to be diseased or in ill health and the cause can be investigated. Through this, causes such as infections, traumas, genetics, degenerative diseases and cancers have been discovered.

What examples are there of biological knowledge contributing to human health?

The biological model shows that health is due to physiological processes in the body and ill health is also due to physiological processes in the body and those biological processes have a chemical (matter and energy) basis. Humans are made of matter and spend a lot of time extracting energy from food; for example, calories are a measure of how much energy some matter, called food, contains. Thus, biology studies the interactions between the internal environment of the body and the external environment in which the body, the organism, lives. It also studies what the body is made from and how that works. All living organisms including humans (but excluding viruses) are made up of cells. Cells are microscopic (can only be seen with a microscope) and can combine to make multicellular tissues, organs and organisms such as humans.

Cell theory

Cells are the smallest functioning unit within which life can be carried out; they are like little chemical factories. Some organisms are composed of just one microscopic cell and are said to be ‘unicellular’. Humans are composed of billions of cells and are thus ‘multicellular’. Cells arise from other cells through growth in size, doubling of the genetic material within the cell, and division of this genetic material between the two new cells. This form of growth is called ‘binary fission’, where one cell divides into two. In multicellular organisms, every cell in the organism’s body is produced from a single cell in a fertilized egg, which then produces progeny cells by binary fission. These then go on to do the same. Humans are composed of about 10¹³ cells (ten trillion cells), each derived from previous cells by this method. All the cells in the embryo and fetus are thus derived from the fertilized egg cell by binary fission using nutrients from outside the fetus to fuel its growth. Figure 1.1 shows a typical animal cell.

Figure 1.1 A typical animal cell

Within each cell are little organs, organelles, which carry out the physiological function of the cell. There are organelles, such as the nucleus, that carry the genetic material we inherited from both our parents, which we copy into each cell in our body. The genes carry the information on how to make proteins. In the cytoplasm are ribosomes where the proteins, which consist of long chains of amino acids, are assembled. Also in the cytoplasm are mitochondria, known as the powerhouse of the cell. Mitochondria are organelles that convert foods into energy.

The main source of food for this is sugar, such as glucose, which is brought to every cell in the body from the digestive tract due to the digestion of sugar-containing foods such as carbohydrates. The sugar in the cell reacts with oxygen brought to the cells from the air in the lungs. Both the sugar from the gastrointestinal (GI) tract and the oxygen from the lungs are transported to every cell in the body by the blood. Once in the cell, the sugar and oxygen react in the mitochondria. From this reaction, energy is released as adenosine triphosphate (ATP). This energy is used to fuel all the reactions of the body, such as contracting muscles, including the muscles of the heart that pump the blood and the muscles that open the lungs to allow air to enter, actively transporting substances across cell membranes, producing hormones, and generating resting potentials in the nervous system that allow us to think. Thus, mitochondria are the energy producers of the cell and the body, vital organelles that allow us to function.

Mitochondria hav...

Table of contents

• Cover
• Title
• Copyright
• Contents
• List of figures
• List of tables
• List of examples
• Notes on contributors
• Acknowledgements
• Abbreviations
• Introducing health studies
• 1 Human biology and health
• 2 History and health
• 3 Epidemiology and health
• 4 Health psychology
• 5 Sociology and health
• 6 Geography and health
• 7 Cultural studies and anthropology
• 8 Politics and health
• 9 Social policy and health
• 10 Organization and management of health and healthcare
• 11 Health economics
• 12 Ethics and law
• Glossary
• Index