The tracheobronchial tree–The course is designed for the basic understanding of anatomical structures and physiological functions of human body, musculoskeletal system, digestive system, respiratory system; cardiovascular system; urinary system, endocrine system, reproductive system, nervous system, hematologic system, sensory organs, integumentary system, and immune system.The aim of the course is to acquire knowledge and skills regarding anatomy and physiology.
The tracheobronchial tree
Pulmonary ventilation
Pulmonary ventilation, refers to the process of exchange of gases between the environment and lungs. Inflation and deflation of the lung occurring with each breath ensures this regular exchange of gases. The aspects and concepts related to pulmonary ventilation which need deliberation include:
- Mechanism of breathing,
- Pressure and volume changes during respiratory cycle,
- Lung volumes and capacities,
- Pulmonary elastance and compliance.
Mechanism of breathing
Pulmonary ventilation is accomplished by two processes:
A. Inspiration
B: Expiration
A. Inspiration
Inspiration refers to inflow of atmospheric air into the lungs. This obviously occurs when the intrapulmonary pressure falls below the atmospheric air pressure. It is an active process, normally produced by contraction of the inspiratory muscles. During tidal inspiration (quite breathing) the diaphragm and external intercostal muscles contract and cause increase in all the three dimensions of the thoracic cavity.
- Role of diaphragm.
- Role of external intercostal muscles.
- Role of laryngeal muscles.
B. Expiration
Expiration refers to outflow of air from the lungs to the atmosphere. This obviously occurs when the intrapulmonary pressure rises above the atmospheric air pressure. Expiration in quit breathing is largely a passive phenomenon and is brought about by the;
- Elastic recoil of the lungs.
- Decrease in size of the thoracic cavity due to relaxation of diaphragm and external intercostal muscles.
(Ref: K. Indu, 1″ ed,P-230)
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