Define breathing. Explain the mechanism of breathing in human beings.
Breathing is a complex mechanical process that involves muscular movement which in turn alters the volume of the thoracic cavity and thereby that of the lungs.
Mechanism of Breathing in Human beings: Breathing occurs involuntarily but its rate is controlled by the respiratory centre of the brain. The space of the thoracic cavity increases or decreases by outward and inward movements of the ribs caused by external intercostal and internal intercostal muscles.
This action is also assisted by the contraction and expansion of the diaphragm. The floor of the thoracic cavity is completely closed by the diaphragm. It is a thin muscular septum separating the abdominal and thoracic cavities.
The inhalation and exhalation of the air take place continuously in the respiratory system. Inspiration or inhalation is concerned with the taking in atmospheric air or oxygen into the thoracic cavity. Expiration or exhalation is concerned with the expelling of carbon dioxide from the lungs. It takes place when the volume of the thoracic cavity decreases and the pressure of the contained air in the thoracic cavity increases.
Breathing is a complex mechanical process that involves muscular movement which in turn alters the volume of the thoracic cavity and thereby that of the lungs.
Mechanism of Breathing in Human beings: Breathing occurs involuntarily but its rate is controlled by the respiratory centre of the brain. The space of the thoracic cavity increases or decreases by outward and inward movements of the ribs caused by external intercostal and internal intercostal muscles.
This action is also assisted by the contraction and expansion of the diaphragm. The floor of the thoracic cavity is completely closed by the diaphragm. It is a thin muscular septum separating the abdominal and thoracic cavities.
The inhalation and exhalation of the air take place continuously in the respiratory system. Inspiration or inhalation is concerned with the taking in atmospheric air or oxygen into the thoracic cavity. Expiration or exhalation is concerned with the expelling of carbon dioxide from the lungs. It takes place when the volume of the thoracic cavity decreases and the pressure of the contained air in the thoracic cavity increases.
