Here are the top interesting facts about major organs and their functions within the respiratory system (RS):

#1 The main function of this system is to obtain the much-needed oxygen from the external environment and transport it to the cells as well as to remove from the human body the carbon dioxide (CO2) which is produced by cellular metabolism.

#2 Another important role of this system is to maintain proper blood pH since too little CO2 causes alkalosis and too much COcauses acidosis.

#3 Some portions of RS are used for non-vital functions, including – speech production, sensing odors, and for straining (especially during coughing or childbirth). In addition, it maintains the human body water levels and the heat balance.

#4 The main parts of this system are as follows – the nose, mouth, trachea, bronchi, bronchioles, lungs (the act of breathing takes place in this part of the system), and the diaphragm.

Nose and Nasal Cavity

#5 It is the entry point for inspired air and the 1st of a series of structures that form the RS. The two openings to the outside (nostrils) allow air to leave or enter the human body during breathing. Nasal hairs (called vibrissae) at the opening of the nostrils capture large particles of dust which might otherwise be inhaled.

#6 Cilia and nasal mucosa also help prevent dust and pathogens from reaching the lungs. Additionally, sneezing helps remove foreign particles which irritate the nasal mucosa. Moreover, the nasal cavity contains structures to resonate the voice and detect chemical odorants.

#7 The sinuses are hollow areas in the bones of the skull which are lined with mucous membranes which open into the nasal cavity. Sinus cavities span all the way to the back of the skull, right above the oral cavity, between the brows and eyes and within the cheekbones.

Oral Cavity

#8 The oral cavity, better known as the mouth, is an external component of the RS. Oral cavity supplements the function of the nasal cavity as well as can act as a substitute in case of nasal blockage.


#9 It acts as a passageway for both respiratory (larynx) system and digestive (esophagus). The pharynx is generally referred to as the throat. Thick fibers of connective tissue and muscle attach the throat to the base of the skull and surrounding structures. Its main purpose is to let inhaled air pass from the nasal cavity to the larynx, trachea, and then the lungs.


#10 The larynx is located at the base of the soft palate and tongue and lies between the trachea (windpipe) and the throat. The larynx is made up of many pieces of tough cartilage, held together by membranes, fibrous tissues, and ligaments. The larynx has an essential role in the respiratory tract by facilitating the air to pass through it and at the same time keeping drink and food from blocking the airway.


#11 The trachea, also referred as the windpipe, filters the air which is inhaled. The lining of the windpipe has a sticky mucous lining which traps foreign substances. It is connected to the tubing system which makes it possible for humans to swallow. The windpipe is only 4 to 5 inches long and approximately three-quarters of an inch in diameter. In addition, the trachea is involved in the production of vocal sounds.


#12 The bronchi are actually the two air tubes which branch off from the windpipe and transport atmospheric air straight into the lungs. Another primary function of the bronchi is to let CO2 out of the lungs and into the windpipe on its way out during exhalation.


#13 They are tiny tubes branch off from the bronchi, extending throughout the lungs. These further divide into smaller tubules, that in turn continue subdividing till they reach the alveoli.


#14 The lungs are found in the chest on the left and right side. At the front, the lungs extend from just above the clavicle (collarbone) at the top of the chest to about the 6th rib down. The left lung contains two lobes or divisions, while the right lung is separated into 3 lobes. The extra space on the left lung leaves room for the heart.

#15 The lungs exchange of gases takes place between the RS and the blood. They consist of small air sacs, that are called the alveoli. Each lung has 300 to 400 million alveoli. The walls of these tiny air sacs allow the oxygen in the air to diffuse into the blood, then, the cardiovascular system transports it to each cell in the human body.

#16 The pleura is a slippery membrane which covers each lung and the inside of the chest wall. Pleura allows the lungs to move smoothly during the respiration process as well as an individual move.


#17 The breathing process is helped by a dome-shaped muscle below the lungs, named – the diaphragm. The diaphragm also separates the chest cavity from the abdominal cavity. The diaphragm and other muscles help the lungs contract and expand so humans can exhale and inhale.