Mechanics of Breathing

Events of Respiration· Pulmonary ventilation – moving air in and

out of the lungs

· External respiration – gas exchange between pulmonary blood and alveoli

·Respiratory gas transport – transport of oxygen and carbon dioxide via the bloodstream

·Internal respiration – gas exchange between blood and tissue cells in bodies capillaries

Pleural lining

• Visceral pleura – Covers the surface of the lungs

• Parietal pleura – Covers the inner surface of the thoracic cavity

• Pleural fluid – Fluid separating two layers– Allows lungs to slide easily past thoracic

walls– Does not allow lungs to separate from

thoracic walls

Mechanics of Breathing (Pulmonary Ventilation)· Completely mechanical process

· Depends on volume changes in the thoracic cavity

· Boyle’s Law: Volume changes lead to pressure changes, which lead to the flow of gases to equalize pressure

·Two phases

· Inspiration – flow of air into lung

· Expiration – air leaving lung

Not these kind……..

Muscles involved in Inspiration

•Diaphragm – The muscle at the base of the ribcage contracts•Intercostal muscles- Muscles between the ribs contract•This process increases the volume of the thoracic cavity

Exhalation / Expiration