Several organs of the respiratory system are responsible for the process of breathing. The nose, pharynx, larynx, trachea, bronchi, and lungs work together to allow gas exchange to occur at the cellular level. Air breathed in through the nose and mouth enters into the lungs at a continual pace to provide a new supply of oxygen the body needs to work properly.
The primary function of the respiratory system is to allow the lungs to take in atmospheric oxygen through inhalation and dispose of the waste products the body does not need through exhalation.
Inhalation is an active motion that causes the diaphragm to contract. During inhalation the diaphragm moves downward as it contracts, increasing the size of the chest cavity. This creates a space of emptiness, which causes air to enter in through the nose or mouth.
Exhalation is a passive process because muscle contraction does not occur. During exhalation, the diaphragm moves back up as the stretched lung bounces back to its normal position. As the lung returns to normal position, carbon dioxide, a waste product created by the body, moves out of the lungs through the mouth and nose.
Functions of Organs in Respiratory System
Respiration begins when oxygen enters into the body through the nose and the mouth. The oxygen then travels through the trachea and pharynx where the trachea divides into two bronchi. Here the bronchi are divided into bronchial tubes, in the chest cavity, so air can be directly moved into the lungs.
The nose is the primary upper respiratory organ in which air enters into and exits from the body. Cilia and mucus line the nasal cavity and traps bacteria and foreign particles that enter in through the nose. In addition, air that passes through the nasal cavity is humidified and moistened.
The nasal septum divides the nose into two narrow nasal cavities: one area is responsible for smell and the other area is responsible for respiration. Within the walls of the nasal cavity there are frontal, nasal, ethmoid, maxillary, and sphenoid bones. Cartilage helps form the shape of the nose.
Besides the nose, air can enter into the lungs through the mouth. The pharynx is a tubular structure, positioned behind the oral and nasal cavities, that allows air to pass from the mouth to the lungs. The pharynx contains three parts: The nasopharynx, which connects the upper part of the throat with the nasal cavity; the oropharynx, positioned between the top of the epiglottis and the soft palate; and the laryngopharynx, located below the epiglottis.
From the pharynx, air enters into the larynx, commonly called the voice box. The larynx is part of the upper respiratory tract that has two main functions: a passageway for air to enter into the lungs, and a source of vocalization. The larynx is made up of the hyoid bone and cartilage, which helps regulate the flow of air. The epiglottis is a flap-like cartilage structure contained in the larynx that protects the trachea against food aspiration.
The bronchi allow the passage of air to the lungs. The trachea is made of c-shaped ringed cartilage that divides into the right and left bronchus. The right main bronchus is shorter and wider than the left main bronchus. The right bronchus is subdivided into three lobar bronchi, while the left one is divided into two lobar bronchi.
The lungs are spongy, air-filled organs located on both sides of the chest cavity. The left lung is divided into a superior and inferior lobe, and the right lung is subdivided into a superior, middle, and inferior lobe. Pleura, a thin layer of tissue, line the lungs to allow the lungs to expand and contract with ease.
Respiration is the primary function of the lungs, which includes the transfer of oxygen found in the atmosphere into the blood stream and the release of carbon dioxide into the air.
The average adult has about 600 million alveoli, which are tiny grape-like sacs at the end of the respiratory tree. The exchange of oxygen and carbon dioxide gases occurs at the alveolar level. Although effort is required to inflate the alveoli (similar to blowing up a balloon), minimal effort is needed to deflate the alveoli (similar to the deflating of a balloon).
The diaphragm is a muscular structure located between the thoracic and abdominal cavity. Contraction of the diaphragm causes the chest or thorax cavity to expand, which occurs during inhalation. During exhalation, the release of the diaphragm causes the chest or thorax cavity to contract.