Mechanics of Respiration I Notes PDF

Mechanics of respiration I Lower Respiratory tract is divided into 23 generations 0 to 16 generation - conducting zone 17 to 23 generation - respiratory zone 0 generation- trachea 16 generation- terminal bronchial 17 generation- respiratory bronchiole 23 generation- alveoli Respiratory acinus (r...

Mechanics of respiration I Lower Respiratory tract is divided into 23 generations 0 to 16 generation - conducting zone 17 to 23 generation - respiratory zone 0 generation- trachea 16 generation- terminal bronchial 17 generation- respiratory bronchiole 23 generation- alveoli Respiratory acinus (respiratory lobule) is the functional unit of the lung. FUNCTION OF RESPIRATORY SYSTEM- Gas exchange- Respiratory system supplies body with O2 and removes CO2 Regulates pH of blood Regulates body temperature Voice production (vocalization) Smell and Taste- Smell receptor is present in olfactory membrane in the roof of nasal cavity, taste receptor in the mouth and pharynx. Mechanism to prevent foreign matters from reaching the alveoli- Particles 10 µ removed from the hairs of the nose Process of Respiration 1- External respiration Pulmonary ventilation : Exchange of gases between lung and atmosphere (process that moves air in and out of the lungs).  Respiratory Rate of pulmonary ventilation = 12-20/min. Pulmonary perfusion: Flow of blood through pulmonary capillaries Pulmonary respiration: Diffusion of gases between the alveoli and blood Internal respiration: Tissue O2 consumption= 200 -250ml/min Boyle law : volume of a gas is inversely proportional to the gas’ pressure in a closed system. Mechanism of Expiration: Expiration is caused by relaxation of inspiratory muscle Effect: decrease the volume of the chest increase the pressure of the chest It is passive process Which of the following muscle involved in deep expiration? A. Diaphragm B. External intercostal C. Abdominal D. Sternomastoid Diaphragm- Principle muscle of inspiration Sternomastoid muscles : They lift the sternum upward Expiration is a passive process during quiet breathing. It is caused by relaxation of inspiratory muscles. The relaxation volume of the lung is 0.6 Liter. The relaxation volume of the chest wall is 5 Liters At the end of normal expiration: the volume of the chest = volume of the lung = 2.3liters At the end of expiration = -2.5 mmHg. During inspiration = -6 mmHg. Deep inspiration = -12 mmHg. IPP (Intrapleural pressure) is always Negative value, Average value= -4 mm Hg TPP (Transpulmonary pressure) is always Positive value, Average value= +4 mm Hg