MEDICAL BIOLOGY, HUMAN ANATOMY, PHYSIOLOGY AND PATHOLOGY - Ya.I. Fedoniuk 2010

ANATOMY, PHYSIOLOGY, PATHOLOGY

CHAPTER 6. THE RESPIRATORY PROCESS AND ITS PATHOLOGY

RESPIRATORY PHYSIOLOGY

PULMONARY VENTILATION

1. MECHANISM OF INSPIRATION AND EXPIRATION

During quiet inspiration, the external intercostal muscles contract, causing the ribs to elevate and the sternum to move forward. As a result, the volume of the thoracic cavity increases in both the frontal and sagittal planes. During quiet inspiration, the diaphragm also contracts, its dome flattens, and the vertical volume of the thoracic cavity increases.

During deep inspiration, auxiliary Respiratory Muscles of the chest and abdomen contract In addition to the Diaphragm.

During quiet breathing, expiration occurs passively due to the elastic energy accumulated during the preceding inspiration.

Forced expiration involves the internal intercostal muscles, abdominal press, etc.



Last update: 08/08/2026

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