The respiratory tract system gives a it is provided of oxygen required by all living cell of the body. Wait is breathed in v the sleep cavity and/or mouth and passes down with the neck (pharynx). The respiratory system additionally makes vocalization feasible as waiting passes end the vocal cords. Different tones and sounds are made by differing the tension of the vocal cords.


The respiratory device is written of the complying with structures:

* Nose- waiting enters the sleep cavity, whereby it is moistened and filtered. It climate passes right into the nasopharynx.

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

o Nasopharynx- situated behind the sleep cavity, the connects the sleep cavity to the oropharynx.

o Oropharynx- a extension of the nasopharynx, it connects the nasopharynx come the laryngopharynx and also serves as a passageway for both food and air.

o Laryngopharynx- serves as a passageway because that both food and air, that connects the oropharynx with the esophagus.

* Larynx- connect the oropharynx through the trachea. It allows air to enter the lungs. The larynx develops a prominence (laryngeal prominence) that is easily seen in adults, described as the Adam"s apple. The larynx has actually nine cartilaginous rings, the biggest of i m sorry is the thyroid cartilage. This rings room attached come the hyoid bone above and the stomach below.

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

* The epiglottis is likewise located within the larynx, and also is attached to the thyroid cartilage ~ above one end. The opposite finish projects into the larynx choose a flap. Throughout swallowing, the larynx is pulled upward, rotating the epiglottis right into a position where the directs solids and fluids into the esophagus and away from the larynx. After ~ swallowing, the epiglottis repositions so that air is directed into the larynx instead of entering the esophagus.

* Trachea (windpipe)- a hollow, tubular structure extending from the larynx come the level the the 7th thoracic vertebrae. It climate divides right into left and also right main bronchi. The trachea is located just anterior to the esophagus. That is a fibrous tubing surrounding by 16-20 C-shaped cartilaginous rings, which support and also maintain the shape. The mucous membrane is lined with cilia (filtration), i m sorry carries impurities away from the lungs towards the pharynx.

* Bronchi

* waiting passes under the trachea, with the left and right main bronchi, and eventually right into the lungs.

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

* secondary bronchi divide into tertiary bronchi.

* These additional divide into numerous bronchioles.

* even the bronchioles divide, forming terminal and also respiratory bronchioles.

* Finally, each respiratory bronchiole divides right into alveolar ducts which contain alveoli, thin walled air sacks wherein oxygen deliver takes place.

* Oxygen in the blood is delivered to human body cells, wherein the oxygen and also glucose in the cells undergo a collection of reaction to provide energy come cells. Waste products of this procedure (mainly carbon dioxide) are carried out that the lungs.


The Lungs

The two lungs are separated through a room called the mediastinum. The heart, aorta, vena cava, pulmonary vessels, esophagus, part of the trachea and bronchi, and the thymus gland are located within the mediastinum.


The lungs are encased through a double-walled security sack, called the pleura. The innermost class of pleura adheres steady to the lung (visceral pleura), if the external layer adheres come the thoracic cavity (parietal pleura). Between these 2 layers the pleura is a narrow fluid filled room called the pleural cavity. Pleural liquid is uncovered within this cavity. The acts as a lubricant to alleviate friction between the two layers together they slide against one one more during expansion and also contraction the breathing. As soon as the pleural membrane i do not care inflamed, the painful condition is referred to as pleurisy. Adhesions in between the 2 layers can occur.


At rest, around 500 ml of wait enters and also leaves the lungs through each respiration cycle. An adult averages around 16 breath cycles every minute. Normally, the thoracic cavity is airtight, sealing the lungs within flexible side walls (ribcage) and a versatile floor (diaphragm). The walls and partitions the the lung lack muscles of your own. Therefore, the lung cannot expand and also contract on its own. This is achieved by the pressure exerted on the lung by the rib cage and diaphragms.

Inspiration ad to moving air into the lungs, if expiration move waste gasses the end of the body. No matter just how forceful expiration is, the is difficult to remove every one of the waiting from the lungs. The staying volume that air in ~ the lungs after expiration is referred to as residual volume. During normal respiration when the patience is in ~ rest, about 500 ml of air move into and out that the lungs. This exchange is described as tidal volume. The complete amount of air exchanged (maximal lot of wait that deserve to be bring away in v deep inspiration compared to the lot of air that leaves the lung after many forceful expiration) is described as critical capacity.

DISEASES the THE respiratory tract SYSTEM

Common Cold- inflammation of the upper respiratory tract caused by viruses. This may be adhered to by bacterial infection of the sinuses, ears or bronchi.

Hay Fever- an allergy antigen-antibody solution to details allergens current in the air.

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Bronchial Asthma- an allergic an answer to international substances that most often go into the body with breathing or food.229

Bronchitis- acute or chronic inflammation the the bronchial tree resulted in by bacterial epidemic or irritants.

Tuberculosis- cavitating infection resulted in by the tubercle bacillus, i beg your pardon gains entry right into the body through inhalation.230 If the human body is unsuccessful in regulating the bacillus, lung organization is destroyed.231, 232

Emphysema- alveoli become over distended and their walls malfunction and are changed by fibrous tissue. This problem usually occurs over a long duration of time second to chronic bronchitis, tobacco smoke, ecological pollutants, and other irritants. This disease is progressive and irreversible.

Pneumonia- inflammation that the lungs, make the affected part of the lung solid and also airless. Most regularly pneumonia is caused by pneumococcus bacterium.

Pleurisy- when the pleural membrane becomes inflamed, visceral and parietal pleural layers deserve to not glide past one an additional without extreme friction.

Pneumothorax- any type of condition that enables air to get in the pleural cavity. Once air enters the pleural space, the lung collapses, a problem known together atelectasis. In many cases, the air is slowly resorbed and an adverse pressure is reestablished, permitting the lung to re-expand.

As us age, the chest wall becomes more rigid and the lungs come to be less elastic, result in lessened ventilation capacity. Clean of the respiratory tract tract becomes less efficient, do elderly patients much more susceptible to infections favor pneumonia.235


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

* manubrium- superior portion of the sternum. The articulates v the medial end of both clavicles. On 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 the the 2nd through 7th ribs.

* xyphoid process- does no articulate with any kind of ribs, but serves as an attachment because that ligaments and muscles.

Throughout life, the sternum has red bone marrow, responsible for the manufacturing of red blood cells.


There are 12 pairs of ribs, consisting of seven pairs that articulate posteriorly with thoracic vertebrae and also anteriorly through the sternum. These first seven bag of ribs are referred to as true ribs, or vertebrosternal ribs. The remaining five pairs are described as false ribs, which articulate v the thoracic vertebrae, however not through the sternum.


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