The respiratory system is the system of the body responsible for carrying out all of the necessary functions to allow a person to breath and acquire oxygen and other substances from the air. Respiration, or the act of breathing, is necessary for all human life, and without it, human beings would be unable to acquire the oxygen needed to carrying out processes in the body that are crucial to life. In order to better understand the respiratory system, it is important to understand the structures located within this system.
The lungs
The first organ than most people think of when they think of the respiratory system is of the lungs. The lungs play a very important and central role in the process of respiration. The lungs are responsible for taking in air and absorbing the oxygen from it, as well as releasing carbon dioxide. The path of air to the lungs starts in the nasal cavity, traveling to the pharynx and trachea, then to what is known as the main bronchus, a fork-like division of the trachea. The air then continues to travel along the lobar bronchi, which are even further branches of the main bronchus. The air continues to travel along more divisions of the bronchi known as the segmental bronchus, bronchiole and terminal bronchiole. The gas exchange then required for respiration takes place in the alveoli which line some of these branches.
The nose and mouth
The nose and mouth are responsible for the intake of oxygen. Humans are able to breathe through either their nose and mouth and these structures are responsible for warming and moisturizing the air a person inhales. The nose, especially, is capable of filtering air by use of guard hairs (vibrissae) which block foreign substances (such as dust, dirt and debris) from entering the lungs through the nose.
The phaynx and larynx
The pharynx can be divided into three subdivisions; the nasopharynx, oropharynx and the laryngopharynx. The pharynx serves as a pathway for stomach-bound food, as well as for air destined for the lungs. The larynx is located below the pharynx and is composed of cartilage and ligatments. The larynx is most commonly thought of as the voicebox and is protected by a piece of cartilagenous tissue known as the epiglottis, which opens and closes the larynx, preventing foods and liquids from entering the trachea. If a substance other than air passes into the larynx, the person begins to cough reflexively.
Trachea
The trachea is most commonly known as the “windpipe,” and is the cartilage encircled tube in the throat located in front of the esophagus. This cartilage prevents the trachea from collapsing during respiration. The trachea is responsible for filtering and transporting air, and branches into the different bronchioles of the lungs.
Pleaura
The pleura located on the lungs is a serous membrane responsible for reducing friction between the lungs and surrounding structures during the expansion and constriction of the lungs during respiration. Additionally, the pleura of the lungs is responsible for creating a pressure gradient which aids in the ability of the lungs to expand due to a lower level of pressure within the lungs than the level of pressure in the surrounding environment.
References
Saladin, Kenneth S.. Anatomy & physiology: the unity of form and function. 5th ed. New York: McGraw-Hill, 2010. Print.
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