Respiratory system

The respiratory system is anatomically divided into the upper and lower respiratory tracts.

• The upper respiratory tract includes the nose, nasal cavity, sinuses, and larynx. These structures are responsible for filtering, warming, and humidifying the air before it reaches the lower respiratory tract.

• The lower respiratory tract consists of the tracheobronchial tree (trachea, bronchi, bronchioles), and lungs. The trachea bifurcates into the right and left main bronchi, which further divide into smaller bronchi and bronchioles, forming a branching tree-like structure. This branching continues until reaching the alveoli, the primary site of gas exchange.

Some sources also includes the pleura in the the respiratory system, a double-layered membrane surrounding the lungs, which provides lubrication and reduces friction during breathing movements.

The pharynx may be included in the upper respiratory tract but is included in alimentary system in Terminologia Anatomica.