The respiratory system gives a supply of oxygen required by every living cell of the body. Wait is breathed in with the nasal cavity and/or mouth and passes down v the neck (pharynx). The respiratory system likewise makes vocalization possible as wait passes end the vocal cords. Various tones and also sounds are made by varying the anxiety of the vocal cords.


The respiratory device is created of the adhering to structures:

* Nose- air enters the nasal cavity, where it is moistened and also filtered. It then passes into the nasopharynx.

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* Pharynx- both food and also air pass through this muscular structure that is lined through a mucous membrane. The pharynx is divided into 3 parts: nasopharynx, oropharynx and laryngopharynx.

o Nasopharynx- located behind the nasal cavity, it connects the nasal cavity come the oropharynx.

o Oropharynx- a extension of the nasopharynx, the connects the nasopharynx come the laryngopharynx and also serves together a passageway because that both food and air.

o Laryngopharynx- serves as a passageway for both food and also air, that connects the oropharynx through the esophagus.

* Larynx- associate the oropharynx through the trachea. It enables air to go into the lungs. The larynx develops a prominence (laryngeal prominence) the is conveniently seen in adults, described as the Adam"s apple. The larynx has actually nine cartilaginous rings, the largest of i m sorry is the thyroid cartilage. These rings are attached come the hyoid bone over and the stomach below.

* The vocal cords are situated within the larynx. There space two pairs of vocal pairs. The top pair is described as the false vocal cords, while the lower pair room the true vocal cords. The opening between the 2 vocal true vocal cords is called the glottis. When the mucous membrane that surrounds the vocal cords i do not care irritated or inflamed, the condition is laryngitis.

* The epiglottis is also located in ~ the larynx, and also is attached come the thyroid cartilage ~ above one end. The opposite finish projects into the larynx favor a flap. During swallowing, the larynx is pulled upward, rotating the epiglottis right into a position where it directs solids and also fluids into the esophagus and away from the larynx. After swallowing, the epiglottis repositions so that air is directed into the larynx instead of start the esophagus.

* Trachea (windpipe)- a hollow, tubular structure prolonging from the larynx come the level of the 7th thoracic vertebrae. It climate divides right into left and right primary bronchi. The trachea is located just anterior to the esophagus. The is a fibrous tubing surrounded by 16-20 C-shaped cartilaginous rings, i m sorry support and also maintain that is shape. The mucous membrane is lined v cilia (filtration), i m sorry carries impurities far from the lungs in the direction of the pharynx.

* Bronchi

* air passes under the trachea, v the left and also right major bronchi, and also eventually into the lungs.

* Each main bronchi divides into secondary bronchi (one for each lobe of the lung).

* an additional bronchi divide right into tertiary bronchi.

* These more divide into plenty of bronchioles.

* also the bronchioles divide, developing terminal and also respiratory bronchioles.

* Finally, each respiratory bronchiole divides right into alveolar ducts i beg your pardon contain alveoli, thin walled wait sacks whereby oxygen transport takes place.

* Oxygen in the blood is ceded to body cells, where the oxygen and also glucose in the cells undergo a collection of reactions to administer energy come cells. Waste commodities of this procedure (mainly carbon dioxide) are carried out that the lungs.


The Lungs

The 2 lungs space separated through a space called the mediastinum. The heart, aorta, vena cava, pulmonary vessels, esophagus, part of the trachea and bronchi, and also the thymus gland are situated within the mediastinum.


The lungs are encased through a double-walled security sack, dubbed the pleura. The innermost great of pleura adheres steady to the lung (visceral pleura), if the external layer adheres come the thoracic cavity (parietal pleura). In between these two layers of pleura is a narrow liquid filled space called the pleural cavity. Pleural fluid is discovered within this cavity. It acts as a lubricant to minimize friction in between the two layers together they slide versus one one more during expansion and contraction that breathing. Once the pleural membrane becomes inflamed, the painful problem is referred to as pleurisy. Adhesions between the 2 layers can occur.


At rest, about 500 ml of air enters and also leaves the lungs with each respiration cycle. One adult averages around 16 breath cycles per minute. Normally, the thoracic cavity is airtight, sealing the lungs within flexible side walls (ribcage) and also a versatile floor (diaphragm). The walls and partitions the the lung absence muscles of their own. Therefore, the lung cannot expand and also contract on its own. This is completed by the pressure exerted on the lung by the rib cage and also diaphragms.

Inspiration refers to moving air right into the lungs, while expiration move waste gasses the end of the body. No matter exactly how forceful expiration is, that is impossible to remove all of the waiting from the lungs. The remaining volume that air within the lung after expiration is described as residual volume. Throughout normal respiration while the patient is in ~ rest, about 500 ml that air move into and also out of the lungs. This exchange is referred to as tidal volume. The complete amount of waiting exchanged (maximal quantity of waiting that can be take away in with deep inspiration contrasted to the lot of wait that pipeline the lung after many forceful expiration) is described as vital capacity.

DISEASES that THE respiratory SYSTEM

Common Cold- inflammation of the upper respiratory tract led to by viruses. This might be complied with by bacterial infection of the sinuses, ear or bronchi.

Hay Fever- an allergic antigen-antibody response to details allergens existing in the air.

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Bronchial Asthma- an allergic response to foreign substances that most often get in the body through breathing or food.229

Bronchitis- acute or chronic inflammation the the bronchial tree caused by bacterial infection or irritants.

Tuberculosis- cavitating infection led to by the tubercle bacillus, i m sorry gains entry right into the body through inhalation.230 If the body is not successful in regulating the bacillus, lung tissue is destroyed.231, 232

Emphysema- alveoli end up being over distended and their walls malfunction and are replaced by fibrous tissue. This condition usually occurs end a long duration of time an additional to chronic bronchitis, cigarette smoke, environmental pollutants, and other irritants. This condition is progressive and also irreversible.

Pneumonia- inflammation of the lungs, do the affected section of the lung solid and airless. Most often pneumonia is led to by pneumococcus bacterium.

Pleurisy- as soon as the pleural membrane i do not care inflamed, visceral and parietal pleural layers have the right to not glide previous one another without extreme friction.

Pneumothorax- any kind of condition that permits air to go into the pleural cavity. As soon as air start the pleural space, the lung collapses, a problem known as atelectasis. In many cases, the air is progressively resorbed and an adverse pressure is reestablished, permitting the lung come re-expand.

As we age, the chest wall surface becomes more rigid and also the lungs end up being less elastic, resulting in reduced ventilation capacity. Cleaning of the respiratory tract becomes much less efficient, making elderly patients much more susceptible to infections choose pneumonia.235


The sternum is a level bone positioned in the anterior chest that forms the anterior wall of the thorax. It has actually three parts: manubrium, body (gladiolus), and xyphoid process.

* manubrium- superior part of the sternum. It articulates v the medial finish of both clavicles. ~ above the lateral side, the articulates through the costal cartilage"s the the 1st and component of the 2nd ribs.

* body (gladiolus)- articulates with the costal cartilage"s of the second through 7th ribs.

* xyphoid process- does not articulate with any kind of ribs, but serves together an attachment because that ligaments and muscles.

Throughout life, the sternum includes red bone marrow, responsible for the production of red blood cells.


There room 12 pairs of ribs, consisting of seven pairs that articulate posteriorly v thoracic vertebrae as well as anteriorly v the sternum. These first seven pairs of ribs are referred to as true ribs, or vertebrosternal ribs. The remaining five pairs are described as false ribs, i beg your pardon articulate v the thoracic vertebrae, yet not v the sternum.


Ribs are linked to the sternum with costal cartilage, a strong hyaline cartilage the is flexible sufficient to allow expansion and also contraction throughout breathing. The eighth, ninth, and tenth bag of ribs have a typical connection anteriorly to an expanded part of costal cartilage. The 11th and 12th ribs are too quick to also articulate with any kind of costal cartilage, and are known as floating (vertebral) ribs.