Chapter 1: The Human Body – An Orientation (Anatomy & Physiology Study Notes)

Form and Function of Anatomy & Physiology

Definitions and Relationship

Understanding the human body requires knowledge of both its structure (anatomy) and function (physiology). These two disciplines are closely related and together explain how the body operates.

• Anatomy: The study of the structure of body parts and their relationships to one another.

• Physiology: The study of the function of body parts; how they work to carry out life-sustaining activities.

Example: The structure of the heart (anatomy) enables it to pump blood (physiology).

Divisions of Anatomy

Gross (Macroscopic) Anatomy

Gross anatomy involves the study of large, visible structures of the body.

• Regional Anatomy: Examines all structures in a particular area of the body (e.g., bones, muscles, blood vessels, and nerves of the arm).

• System Anatomy: Focuses on just one system (e.g., cardiovascular, nervous, muscular systems).

• Surface Anatomy: Studies internal structures as they relate to the overlying skin (e.g., visible muscle masses or veins seen on the surface).

Microscopic Anatomy

Microscopic anatomy deals with structures too small to be seen with the naked eye.

• Cytology: The microscopic study of cells.

• Histology: The microscopic study of tissues.

Developmental Anatomy

Developmental anatomy studies anatomical and physiological development throughout life.

• Embryology: The study of developments before birth.

To study anatomy, one must know anatomical terminology and be able to observe, manipulate (move the articulation), palpate (feel the organs with the hands), and auscultate (listen to organ sounds with a stethoscope).

Divisions of Physiology

Overview

Physiology is often divided based on organ systems and focuses on cellular and molecular levels.

• Organ System Physiology: Examples include renal physiology (kidneys) and cardiovascular physiology (heart and blood vessels).

• Physiology examines how the body's abilities depend on chemical reactions in individual cells.

• Understanding physiology requires knowledge of basic physical principles (e.g., electrical currents, pressure, movement) and chemical principles.

Complementarity of Structure and Function

Principle of Complementarity

The function of a body part always reflects its structure. This is known as the principle of complementarity of structure and function.

• Example: The sharp edges of incisors (structure) make them ideal for cutting like scissors (function), while the flat surfaces of molars (structure) make them ideal for grinding, like a mortar and pestle (function).

Levels of Structural Organization

Hierarchy of Organization

The human body is organized into several levels, each building on the previous one:

• Chemical Level: Atoms combine to form molecules.

• Cellular Level: Cells are made up of molecules and are the basic unit of life.

• Tissue Level: Tissues consist of similar types of cells working together to perform a specific function.

• Organ Level: Organs are made up of different types of tissues.

• Organ System Level: Organ systems consist of different organs that work closely together.

• Organismal Level: The human organism is made up of many organ systems working together to maintain life.

Example: The cardiovascular system includes the heart and blood vessels, which transport blood throughout the body.