Respiratory system


The function of the respiratory system is to provide the body with an exchange of gases with atmospheric air, ensuring the permanent concentration of oxygen in the blood necessary for metabolic reactions, and in return serving as a means of eliminating waste gases that result from these reactions and which are represented by the gas carRespiratory system Bonic.
This system consists of the upper and lower respiratory tract (airways). The upper respiratory tract consists of organs located outside the rib cage: external nose, nasal cavity, pharynx, larynx, and upper trachea. The lower respiratory tract consists of organs located in the thoracic cavity: lower part of the trachea, bronchi, bronchioles, alveoli, and lungs. The layers of the pleura and the muscles that form the thoracic cavity are also part of the lower respiratory tract. The exchange of gases takes place at the level of the lungs, but to reach them the air must travel through several portions of an irregular tube, which receives the joint name of airways.

Airways can be divided into: NOSE, FARING, LARING, Trachea, Bronchi and LUNGs.



The nose is a bulge located in the center of the face, the outer part of which is called the external nose and the excavation that is internally known as the nasal cavity.

The outer nose is in the shape of a lower base triangular pyramid whose rear face vertically fits the middle 1/3 of the face.

The lateral faces of the nose have a semilunar protrusion that is called the nose wing.

Air enters the respiratory tract through two openings called Nostrils. It then flows through the right and left nasal cavities, which are lined with respiratory mucosa. The nasal septum separates these two cavities. The hairs inside the nostrils filter out large dust particles that can be inhaled. In addition, the nasal cavity contains receptor cells for smell.

Outer Nose Structures


The nasal cavity is the excavation we find inside the nose, it is subdivided into two compartments one right and one left. Each compartment has an anterior hole which is the Nostril and a later called Coana. The choanas make the communication of the nasal cavity with the pharynx. It is in the nasal cavity that air becomes conditioned, that is, it is filtered, moistened and heated.


Nostril and Nasal Septum




In the lateral wall of the nasal cavity we find the Nasal Shells (turbinates) which are divided into Superior, Medium and Lower.

Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

The bony skeleton of the nose is formed by the frontal bone, nasal and jaw bones.

The nasal cavity contains several drainage openings through which mucus from the paranasal sinuses is drained. The Paranasal Breasts understand the breasts jaws, front, ethmoidal it's the sphenoidal.


Paranasal Sinuses or Breasts of the Face - Lateral and Anterior Views

Paranasal Sinuses or Breasts of the Face & #8211; Side and Anterior Views


Pharynx PortionsPHARYNX

The pharynx is a tube that begins in the choanae and extends down the neck. It lies just behind the nasal cavities and just in front of the cervical vertebrae. Its wall is composed of skeletal muscles and lined with mucous tunic. The pharynx acts as an air and food passage. The pharynx is divided into three anatomical regions: Nasopharynx, Oropharynx and Laryngopharynx.
The upper portion of the pharynx, called the nasal or Nasopharynx, has the following communications: two with the choanae, two pharyngeal ostia of the auditory tube and the oropharynx. The ear tube communicates with the pharynx through the pharyngeal bone of the ear tube, which in turn connects the nasal part of the pharynx with the tympanic middle ear cavity.
The middle part of the pharynx, the oropharynxIt lies behind the oral cavity and extends from the soft palate to the hyoid level. The oropharynx part communicates with the mouth and serves as a passageway for both air and food.

The laryngopharynx It extends downward from the hyoid bone, and connects with the esophagus (food canal) and anteriorly with the larynx (air passage). Like the oral part of the pharynx, the laryngopharynx is a respiratory tract as well as a digestive tract.

Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.


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The larynx is a short organ that connects the pharynx with the trachea. It lies on the midline of the neck, facing the fourth, fifth and sixth cervical vertebrae.

The Larynx Has Three Functions:

 It acts as an airway during breathing;

 Produces sound, ie the voice (for this reason it is called the voice box);

 Prevents food and foreign objects from entering respiratory structures (such as the trachea).

The larynx plays a role in sound production, which results in phonation. On its inner surface we find an anteroposterior fissure called the laryngeal vestibule, which has two folds: vestibular fold (false vocal cords) and vocal fold (true vocal cords).

Vocal Fold Changes

The larynx is a triangular structure consisting mainly of cartilage, muscles and ligaments.

The larynx wall is made up of nine pieces of cartilage. Three are odd (Thyroid Cartilage, Cricoid and Epiglottis) and three are pairs (Arytenoid, Cuneiform and Corniculate Cartilage).

THE Thyroid Cartilage Consists of hyaline cartilage and forms the anterior and lateral laryngeal wall, is larger in men due to the influence of hormones during the puberty phase. The posterior margins of the blades have extensions in thick and short stylet shapes, called superior and inferior horns.

Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

THE Cricoid Cartilage It is located just below the thyroid cartilage and precedes the trachea.

THE Epiglottis it attaches to the hyoid bone and thyroid cartilage. The epiglottis is a species of & #8220; door & #8221; to the lung, where only air or gaseous substances enter and leave it. Already liquid and solid substances do not enter the lung, because the epiglottis closes and it goes to the esophagus.


Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.

THE Arytenoid Cartilage articulates with the cricoid cartilage, establishing a diarrhea-like joint. Arytenoid cartilages are the most important because they influence the positions and tensions of the vocal folds (true vocal cords).

THE Corniculate Cartilage It lies above the arytenoid cartilage.

THE Cuneiform Cartilage It is very small and is anterior to the corresponding corniculated cartilage, linking each arytenoid to the epiglottis.

Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.


The trachea is a tube 10 to 12.5 cm long and 2.5 cm in diameter. It is a tube that continues the larynx, penetrates the thorax and ends by bifurcating into the 2 main bronchi. It is situated medium and anterior to the esophagus, and only at its termination, deviates slightly to the right.

The tracheal framework consists of approximately 20 incomplete backward cartilage rings, which are called tracheal cartilages.

Internally the trachea is lined with mucosa, where glands abound, and the epithelium is ciliated, facilitating the expulsion of mucosities and foreign bodies.

Inferiorly the trachea forks, giving rise to the 2 main bronchi: right and left.

The lower part of the junction of the main bronchi is occupied by an anteroposterior protrusion that is called the carina of the trachea, and serves to accentuate the separation of the 2 bronchi.

Trachea & #8211; PREVIOUS VIEW
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.


The main bronchi connect the trachea to the lungs, are considered right and left. The trachea and extrapulmonary bronchi consist of incomplete rings of hyaline cartilage, fibrous tissue, muscle fibers, mucosa, and glands.

The right main bronchus is more vertical, shorter and wider than the left. Like the trachea, the main bronchi contain incomplete cartilage rings.

The main bronchi enter the lungs in the region called HILO. Upon reaching the corresponding lungs, the main bronchi are subdivided into the Lobar Bronchi.

The lobar bronchi are subdivided into Segmental Bronchi, each of these being distributed to a pulmonary segment.

The bronchi are divided respectively into smaller and smaller tubes called Bronchioles. The walls of the bronchioles contain smooth muscle and have no cartilage.

The bronchioles continue to branch, and give rise to tiny tubules called Alveolar Ducts.

These ducts end in grape-like microscopic structures called Alveoli.

The alveoli are tiny air sacs that form the end of the airway. A pulmonary capillary surrounds each socket.

The Function of the Alveoli It is to exchange oxygen and carbon dioxide through the alveolar-pulmonary capillary membrane.


Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.



Right lung

* Tables outlining the lobar and segmental bronchi of each lung. The images can be viewed below.

Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.


Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.



The lungs are essential organs in breathing. They are two viscera on either side, inside the chest and where the atmospheric air meets the circulating blood, and then gas exchange (HEMATOSIS) occurs. They extend from the diaphragm to just above the clavicles and are juxtaposed to the ribs. The right lung is thicker and wider than the left. It is also slightly shorter as the diaphragm is taller on the right side to accommodate the liver. The left lung has a concavity that is the cardiac notch. Each lung has a shape that resembles a pyramid with an apex, a base, three edges, and three faces.


LungApex of the Lung: It is cranially oriented and has a slightly rounded shape. It presents a groove traversed by the subclavian artery, called subclavian artery groove. In the body, the lung apex reaches the level of the sternoclavicular joint

Lung Base: The base of the lung is concave in shape, resting on the upper surface of the diaphragm. The concavity of the right lung base is deeper than the left one (due to the presence of the liver).

Lung Margins: The lungs have three margins: one Previous, an Later is Bottom.

Lung Edges: The anterior border is thin and extends to the ventral face of the heart. The anterior border of the left lung has a notch produced by the heart, the cardiac notch. The posterior border is blunt and protrudes on the posterior surface of the thoracic cavity. The lower border has two portions: (1) one that is thin and protrudes into the costophrenic recess and (2) one that is more rounded and protrudes into the mediastinum

Weight: The lungs average 700 grams.

Height: The lungs have an average height of 25 centimeters.

Faces: The lung has three faces:

Lung with Diaphragm The) Costal Face (lateral face)It is the relatively smooth and convex face facing the inner surface of the thoracic cavity.

B) Diaphragmatic Face (lower face): is the concave face that rests on the diaphragmatic dome.

W) Mediastinal Face (Medial Face): is the face that has a concave region where the heart is accommodated. Dorsally lies the region called the hilum or root of the lung.

Division: The lungs have different morphological characteristics.

The Right Lung It consists of three wolves divided by two fissures. An oblique fissure that separates the lower lobe from the middle and upper lobes and a horizontal fissure that separates the upper lobe from the middle lobe.

The Left Lung It is divided into an upper lobe and a lower lobe by an oblique fissure. Anteriorly and inferiorly the upper lobe of the left lung has a structure that represents remnants of the embryonic development of the middle lobe, the lung lingula.

Each pulmonary lobe is subdivided into pulmonary segments, which constitute complete pulmonary units, considered anatomically autonomous.

Right lung

* Superior wolf: apical, anterior and posterior
* Medium wolf: medial and lateral
* Lower Wolf: apical (superior), anterior basal, posterior basal, medial basal and lateral basal

Left lung

* Superior wolf: apicoposterior, anterior, superior lingular and inferior lingular
* Lower Wolf: apical (superior), anterior basal, posterior basal, medial basal and lateral basal




Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.


Pleural SpaceThe outer surface of each lung and the inner wall of the rib cage are lined with a double serous membrane called pleura. The membrane on the outer surface of each lung is called Visceral Pleura, and the one that lines the chest cavity wall is called Parietal Pleura.

Between the visceral and parietal pleura is a small space, the pleural cavity, which contains a small amount of lubricating fluid secreted by the tunics. This fluid reduces friction between the tunics, allowing them to slip easily over each other during breathing.

Lung Hilo:

The hilum region is located on the mediastinal face of each lung being formed by the structures that arrive and leave it, where we have: Main Bronchi, Pulmonary Arteries, Pulmonary Veins, Bronchial Arteries and Veins and Lymphatic Vessels.

The bronchi occupy caudal and posterior position, while the pulmonary veins are inferior and anterior. The pulmonary artery occupies a superior and median position in relation to these two structures. The root of the right lung is dorsally arranged in the superior vena cava. The root of the left lung is previously related to the Phrenic Nerve. It later relates to the vagus nerve.

Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.
Source: NETTER, Frank H .. Atlas of Human Anatomy. 2 ed. Porto Alegre: Artmed, 2000.