Structure of Respiratory System

Structure of the Respiratory System

The respiratory system primarily consists of the nose, mouth, throat, larynx, trachea, bronchi, bronchioles, and lungs. Its main function is to allow for gas exchange (oxygen and carbon dioxide) between the atmospheric air and the blood.
Beginning with the nose and mouth; these are the main external openings that allow air to enter the respiratory system. The nose is better adapted for breathing as it has hairs and mucus to filter, warm, and moisten the incoming air.
The throat, or pharynx, is a tube-like structure that connects the nose and mouth to the larynx (voice box).
The larynx both routes air and food into the correct channels and plays a crucial role in speech production. The ‘Adam’s apple’ is the protective piece of cartilage that sticks out in the front of the neck.
The trachea, also known as the windpipe, is a tube that connects the larynx to the bronchi. The trachea is lined with cilia which are tiny hairs that sweep upwards, moving mucus and unwanted particles out of the lungs.
The trachea splits off into two bronchi (singular: bronchus) which lead to the left and right lungs. These bronchi then split into smaller bronchioles.
The bronchioles end in tiny air sacs called alveoli. It is here that the actual gas exchange occurs. Each lung contains about 300-500 million alveoli.
The separating wall between the alveoli and capillaries (blood vessels) is extremely thin—allowing oxygen and carbon dioxide to move across the wall easily (diffusion process).
Finally, the lungs themselves are pair organs located on either side of the chest cavity. The right lung is larger and has three lobes, while the left lung has two lobes.
Each lung is covered by a pleural membrane that provides lubrication to reduce friction between the lungs and the chest wall during breathing.
Although not part of the respiratory tract, the lungs are also closely associated with the diaphragm muscle. The contractions and relaxations of the diaphragm allow for the mechanical process of inhalation and exhalation.

Understanding the structure of the respiratory system is vital to understanding both how we breathe and how our bodies acquire the oxygen we need.