LESSON 7
THE HUMAN RESPIRATORY SYSTEM AND BREATHING
Section I. INTRODUCTION
7-1. PURPOSE OF RESPIRATION AND BREATHING
a. The processes of respiration and breathing serve to provide oxygen to the
body cells. This oxygen is used in the process of metabolic oxidation. In metabolic
oxidation, the energy trapped in glucose molecules is released for use in the body's
activities.
b. Also, the carbon dioxide (CO2) produced during metabolic oxidation and any
other unwanted gases are removed from the body.
7-2. DEFINITIONS
a. Respiration. In general, respiration is the exchange of gases. In the human
body, two kinds of respiration take place.
(1) External respiration. In external respiration, gases are exchanged
between the blood and the surrounding air.
(2) Internal respiration. In internal respiration, gases are exchanged between
the blood and the individual cells of the body.
b. Breathing. On the other hand, breathing is the process by which air is
moved into and out of the lungs.
(1) Types. In humans, there are two types of breathing. In costal breathing,
the rib cage is used. In diaphragmatic breathing, there is reciprocal interaction between
the diaphragm and the abdominal wall.
(2) Direction of air flow. When the air flows inward, we call it inhalation
(inspiration). When the air flows outward, we call it exhalation (expiration).
7-3. PHYSICAL PRINCIPLES
Both respiration and breathing are essentially physical processes. Air and/or
various gases are moved from one place to another. Their movement is because of
differences in their relative pressures from one space to another.
MD0007
7-2
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