Associated structures within the respiratory tract include the [[Paranasal sinuses - Anatomy & Physiology|paranasal sinuses]], the [[Pleural cavity and membranes - Anatomy & Physiology|pleural cavity & membranes]] and the [[Guttural pouches - Anatomy & Physiology|guttural pouches]]. | Associated structures within the respiratory tract include the [[Paranasal sinuses - Anatomy & Physiology|paranasal sinuses]], the [[Pleural cavity and membranes - Anatomy & Physiology|pleural cavity & membranes]] and the [[Guttural pouches - Anatomy & Physiology|guttural pouches]]. |