Changes

Air is [[Ventilation - Anatomy & Physiology|inhaled]] and passes through the upper respiratory tract via the nares, [[Nasal cavity - Anatomy & Physiology|nasal cavity]], [[Pharynx - Anatomy & Physiology|pharynx]], [[Larynx - Anatomy & Physiology|larynx]], and [[Trachea - Anatomy & Physiology|trachea]]; it is  heated and moistened en route. It then passes to the lower respiratory tract traveling through the [[Lungs - Anatomy & Physiology|lungs]] via the [[Bronchi and bronchioles - Anatomy & Physiology|bronchi, bronchioles]] and [[Lungs - Anatomy & Physiology|alveoli]] where oxygen diffuses across the alveolar wall and into the blood, forming oxyhaemoglobin. The active process of continuous [[Gas Exchange - Anatomy & Physiology|gas exchange]] in the lungs is known as [[Ventilation - Anatomy & Physiology|ventilation]].

Air is [[Ventilation - Anatomy & Physiology|inhaled]] and passes through the upper respiratory tract via the nares, [[Nasal cavity - Anatomy & Physiology|nasal cavity]], [[Pharynx - Anatomy & Physiology|pharynx]], [[Larynx - Anatomy & Physiology|larynx]], and [[Trachea - Anatomy & Physiology|trachea]]; it is  heated and moistened en route. It then passes to the lower respiratory tract traveling through the [[Lungs - Anatomy & Physiology|lungs]] via the [[Bronchi and bronchioles - Anatomy & Physiology|bronchi, bronchioles]] and [[Lungs - Anatomy & Physiology|alveoli]] where oxygen diffuses across the alveolar wall and into the blood, forming oxyhaemoglobin. The active process of continuous [[Gas Exchange - Anatomy & Physiology|gas exchange]] in the lungs is known as [[Ventilation - Anatomy & Physiology|ventilation]].

Associated structures of veterinary interest 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]].

Other associated structures of veterinary interest 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]].

==Cardiovascular System==

==Cardiovascular System==