Introduction to Anatomy and Physiology

Introduction to Anatomy and Physiology

The human body consists of many different parts. It is highly complex, both in terms of structure and function. Overall, the human body appears to function as a single unit. However, it is made up of many different parts whose functions are dependent on one another. Different body parts perform different functions which are sometimes related. For the body to be normal and healthy, all the different parts have to work properly.

Different parts of the body do not work independently. Rather they work in coordination with one another. If one part fails to function normally, it can affect other parts and also the whole body. The organism’s ability to survive depends on the functioning of all the body parts.

Anatomy and Physiology


Anatomical study by Leonardo da Vinci


Anatomy is the branch of biology which deals with the study of the structure of organisms and their parts. It is closely related to embryology, comparative anatomy, evolutionary biology and phylogeny. Human anatomy is considered as one of the basic essential sciences of medicine.

Anatomy is divided into two sub-disciplines:

  • Macroscopic anatomy (or gross anatomy): Study of structures large enough to be seen with the naked eye. It includes superficial anatomy or surface anatomy which can be defined as the study by sight of external body features.
  • Microscopic anatomy: Study of structures on a microscopic scale using optical instruments. It includes histology (study of tissues) and embryology (study of embryos and their development)

Anatomy involves study using both invasive and non-invasive methods for obtaining information about the various organs and systems of the body. Methods of study include dissection (cutting of the body to study its structure) and endoscopy (use of a flexible tube with a light and camera attached to it to study internal organs).

The term “anatomy” is commonly used to refer to “human anatomy”.


Physiology is the scientific study of functioning of living systems. It focuses on how biomolecules, cells, tissues, organs and organ systems function. Human physiology tries to understand the mechanical, physical and biochemical mechanisms that keep the human body alive.


Pathology is the study of diseases and disorders and how they affect the functioning of the body. It is mainly concerned with the examination of organs, tissues, and bodily fluids in order to make a diagnosis of disease. Pathology is a major field in modern medicine. A physician practicing pathology is known as a pathologist.

Pathology addresses four components of disease:

  • Etiology i.e. the cause of the disease
  • Pathogenesis i.e. mechanisms of development of the disease
  • Morphologic changes i.e. structural changes in the cells
  • Clinical manifestations i.e. the consequences of the changes

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Topics in this Section

Levels of complexityInternal environment and homeostasisNegative feedback mechanisms
Positive feedback mechanismsSurvival needs of the bodyCommunication
Transport systemsInternal communicationCommunication with external environment
Intake of raw materialsElimination of wastesProtection and survival
AgeingStudy of illness