Anatomy

The respiratory system includes:- the nostrils; - the nasal cavity, which is always very short;- the larynx, a hollow organ that regulates air flow between the pharynx and trachea;- the trachea, a single, flexible, wide tube (8 cm long), which is a continuation of the larynx;- the bronchi, passages branching off from the trachea into the lungs to ensure air circulation;- the two lungs, a right lung and a left lung. Spongy and elastic, they share the thoracic cavity with the heart.Each is surrounded by the pleura. The lungs account for 1% of the body weight.The right lung, which is longer, consists of four lobes: the caudal, middle, cranial, and accessory lobes.The left lung consists of three lobes: the caudal, middle, and cranial lobes.