Introduction to Anatomy & Physiology

Definition and Scope

Anatomy and Physiology (A&P) are foundational sciences in understanding the human body. Anatomy focuses on the structure of body parts, while physiology explores their functions and how they work together to sustain life.

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

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

Complementarity of Structure and Function

Principle of Complementarity

Anatomy and physiology are inseparable because function always reflects structure. The specific function of a body part depends on its form, a concept known as the principle of complementarity of structure and function.

• Example: The sharp edges of incisors (structure) make them ideal for cutting food (function), while the flat surfaces of molars (structure) are suited for grinding.

Topics of Anatomy & Physiology

Subdivisions of Anatomy

• Gross or Macroscopic Anatomy: Study of large, visible structures.

  • Regional Anatomy: Looks at all structures in a particular area of the body.

  • System Anatomy: Examines body systems (e.g., cardiovascular, nervous).

  • Surface Anatomy: Studies internal structures as they relate to the overlying skin.

• Microscopic Anatomy: Study of structures too small to be seen with the naked eye.

  • Cytology: Study of cells.

  • Histology: Study of tissues.

• Developmental Anatomy: Studies anatomical and physiological development throughout life.

  • Embryology: Study of developments before birth.

Subdivisions of Physiology

• Based on organ systems (e.g., renal or cardiovascular physiology).

• Often focuses on cellular and molecular levels of the body.

• Looks at how the body's abilities are dependent on chemical reactions in individual cells.

Requirements for Life

Necessary Life Functions

To maintain life, organisms must perform several essential functions:

• Maintaining Boundaries: Separation between internal and external environments (e.g., plasma membranes, skin).

• Movement: Muscular system allows movement of body parts and substances (e.g., blood, food).

• Responsiveness: Ability to sense and respond to stimuli (e.g., withdrawal reflex, breathing rate changes).

• Digestion: Breakdown of ingested foodstuffs, followed by absorption of simple molecules into the blood.

• Metabolism: All chemical reactions in body cells, including catabolism (breakdown) and anabolism (synthesis).

  • Equation:

• Excretion: Removal of wastes from metabolism and digestion (e.g., urea, carbon dioxide, feces).

• Reproduction: At the cellular level, involves division of cells for growth or repair; at the organismal level, production of offspring.

• Growth: Increase in size of a body part or organism.

Organization of the Human Body

Multicellularity and Organ Systems

• Humans are multicellular; to function, individual cells must be kept alive.

• Organ systems are designed to service the cells, and all cells depend on organ systems to meet their survival needs.

• There are 11 organ systems that work together to maintain life.

The Body's Organ Systems and Their Major Functions