The human body is rather like a highly technical and sophisticated machine. It operates as a single entity, but is made up of a number of systems that work interdependently. Each system is associated with a specific, and sometimes related, function that is normally essential for the wellbeing of the individual.
Should one system fail, the consequences can extend to others, and may reduce the ability of the body to function normally. Integrated working of the body systems ensures survival. The human body is therefore complex in both structure and function, and this book aims to explain the fundamental structures and processes involved.
Anatomy is the study of the structure of the body and the physical relationships between body systems. Physiology is the study of how the body systems work, and the ways in which their integrated activities maintain life and health of the individual. Pathology is the study of abnormalities and how they affect body functions, often causing illness.
The final section of this chapter provides a framework for studying diseases, an outline of mechanisms that cause disease and some common disease processes. Building on the normal anatomy and physiology, relevant illnesses are considered at the end of the later chapters.