Mammal

• With mammals, gaseous exchange takes place in the lungs
• The gaseous exchange surface inside the lungs consists of millions of alveoli, which significantly increase the surface area
• The walls of the alveoli are thin and consist of a single layer of squamous epithelium, the walls of the alveoli are lined with a thin layer of moisture. The alveoli are surround by a system of blood capillaries for efficient transport of gases
• The movement of the ribs, diaphragm and intercostal muscles increase and decrease the volume and pressure in lungs and thoracic cavity, so efficient ventilation takes place.
• The lungs are protected by the intrapleural fluid between the two pleura that surrounds the lungs; the chest and intercostal muscles also serve to protect them.