Introduction to Physiology: Functional Organization of the Human Body

Vocabulary terms and definitions related to the functional organization of the human body, cell units, and the concept of the internal environment.

Physiology

The science that seeks to explain the physical and chemical mechanisms that are responsible for the origin, development, and progression of life.

Human Physiology

The science that attempts to explain the specific characteristics and mechanisms of the human body that make it a living being.

Pathophysiology

The study of disordered body function and the basis for clinical medicine.

Cell

The basic living unit of the body; each tissue or organ is an aggregate of many different cells held together by intercellular supporting structures.

Red blood cells

The most abundant type of single cell in the body, numbering about $25$ trillion in each person, which transport oxygen from the lungs to the tissues.

Total human cell count

The entire human body contains approximately $35$ to $40$ trillion human cells.

Microbiota

Communities of microorganisms that inhabit the body, living on the skin and in the mouth, gut, and nose.

Gastrointestinal microbiota population

A complex and dynamic population of $400$ to $1000$ species of microorganisms that normally inhabit the gastrointestinal tract and outnumber human cells.

Internal Environment

A term referring to the extracellular fluid, which consists of a water solution of ions and other substances.

Adult human body fluid percentage

Approximately $50\%$ to $70\%$ of the adult human body is composed of fluid.