The Respiratory System Overview

Overview of Respiration

• Respiration has three main functions: taking in oxygen, excreting carbon dioxide, and regulating blood composition.

Inspiration and Expiration

• Inspiration is an active process that expands the lungs inside the thorax, caused by muscle contraction.
• Expiration is a passive process that reduces lung volume, caused by muscle relaxation.
• Lungs are elastic and depend on the thoracic walls for support.
• If air enters the space between the thoracic wall and lungs, one or both lungs will collapse.

The Respiratory Center

• The respiratory center stimulates respiration when carbon dioxide levels are too high.
• When carbon dioxide levels fall too low, the respiratory center slows down respiration.

The Trachea and Airways

• Air is inhaled through the nose and mouth, then passes through the pharynx and larynx to the trachea.
• The trachea is a muscular tube that divides into two primary bronchi at its lower end.

Gas Exchange

• The alveoli and capillaries are responsible for exchanging oxygen and carbon dioxide.

Coughing Mechanism

• Coughing is a forced expiratory effort that removes large amounts of mucus and foreign materials from the airways.
• Dust and other foreign materials are inhaled with every breath, and excess mucus is removed by coughing.

Learn about the functions of respiration, including taking in oxygen and excreting carbon dioxide, and understand the processes of inspiration and expiration.