Physiology of respiratory system

The respiratory system has one main function which is to provide oxygen for the body and release carbon dioxide. To achieve this main function it has to pass through the following stages

  • Pulmonary ventilation

  • Diffusion of oxygen and carbon dioxide in opposite direction between alveoli and blood

  • Transport of respiratory gases -oxygen and carbon dioxide in the blood, body fluids and tissues

  • Regulation of ventilation

  • Pulmonary ventilation

Cough reflex

Irritants in the respiratory epithelium triggers off the mechanism that lead to cough. These irritants, whether chemical or mechanical, cause the respiratory system to go into coughing when they occur in the respiratory tree aside from the lungs. In the lungs it causes rapid shallow breathing with bronchoconstriction and not coughing.

Deep inspiration is followed by forced expiration against a closed glottis in cough. Then the glottis is opened suddenly forcing an explosion of air at velocity of about 965 km per hour that help to expel irritants from the airways.

Sneeze reflex

Sneezing is similar to cough and performs the same function of clearing irritants from the airways but cough comes with mucous expectoration while sneezing does not. Also there is no closure of glottis in sneezing.

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