1.1: Overview of Anatomy and Physiology

Human anatomy is the scientific study of the body's structures. Some of these structures are very small and can only be observed and analyzed with the assistance of a microscope. Other larger structures can readily be seen, manipulated, measured, and weighed. The word "anatomy" comes from a Greek root that means "to cut apart." Human anatomy was first studied by observing the body's exterior and the wounds of soldiers and other injuries. Later, physicians were allowed to dissect the bodies of the dead to augment their knowledge. When dissecting a body, its structures are cut apart to observe their physical attributes and relationships to one another. Dissection is still used in medical schools, anatomy courses, and pathology labs. However, several imaging techniques have been developed to observe structures in living people. These techniques allow clinicians to visualize structures inside the living body, such as a cancerous tumor or a fractured bone.

Anatomists take two general approaches to the study of the body's structures: regional and systemic. Regional anatomy is the study of the interrelationships of all of the structures in a specific body region, such as the abdomen. Studying regional anatomy helps us appreciate the interrelationships of body structures, such as how muscles, nerves, blood vessels, and other structures work together to serve a particular body region. In contrast, systemic anatomy is the study of the structures that make up a discrete body system—that is, a group of structures that work together to perform a unique body function. For example, a systemic anatomical study of the muscular system would consider all of the skeletal muscles of the body.

Whereas anatomy is about structure, physiology is about function. Human physiology is the scientific study of the chemistry and physics of the body's structures and how they work together to support the functions of life. Much of the study of physiology centers on the body's tendency toward homeostasis. Homeostasis is the state of steady internal conditions maintained by living things. The study of physiology certainly includes observation, both with the naked eye and microscopes, as well as manipulations and measurements. However, current advances in physiology usually depend on carefully designed laboratory experiments that reveal the functions of the many structures and chemical compounds that make up the human body.

This text is adapted from Openstax, Anatomy and Physiology 2e, Section 1.1: Section Title Overview of Anatomy and Physiology

The human body is a complex system studied in two branches of biology— anatomy and physiology.

Anatomy studies the structure of the body and the organization of different body parts. It is further divided into gross and microscopic anatomy.

Gross or macroanatomy examines large body parts, such as the heart and bones, without using a microscope. 

In contrast, microscopic anatomy or microanatomy investigates individual cells and tissues using a microscope.

Physiology studies how different parts of the body function and the mechanisms that drive these functions. Based on the level of organization, physiology can be further classified into molecular, cellular, and systemic. 

Systemic physiology can be further subdivided by organ systems. These divisions include cardiovascular physiology, which studies the heart and blood systems, and neurophysiology, which studies the nervous system.

The principle of complementarity of structure and function states that human anatomical structures support their physiological function. For example, muscles contain contractile cells allowing them to move the body.