Trace the sequence of anatomical structures from the sleep to the pulmonary alveoli.Explain the complying with terms: top respiratory tract, reduced respiratory tract.Explain why the alveoli do not collapse as soon as one exhales.Relate the function of any section of the respiratory tract to its gross and microscopic anatomy.

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The significant organs that the respiratory system role primarily to administer oxygen to body tissues for cellular respiration, remove the waste product carbon dioxide, and help to keep acid-base balance. Portions of the respiratory system are additionally used because that non-vital functions, such together sensing odors, speech production, and for straining, together as during childbirth or coughing.

Figure 1. The significant respiratory structures expectations the sleep cavity to the diaphragm.

Functionally, the respiratory tract system can be divided into a conducting division and a respiratory division. The conducting division of the respiratory system includes the organs and structures not directly associated in gas exchange. The gas exchange wake up in the respiratory division.

Conducting Division

The significant function of the conducting division is to carry out a course for incoming and outgoing air. While wait is beginning the respiratory tract system, the conducting department must prepare the air for the lungs. This preparation includes:

removing debris and also pathogens indigenous the incoming airwarming the incoming airhumidifying the incoming air

Each part of the conducting division is very closely structured to maximize its capacity to warm, moisten, and clean the wait entering the respiratory division. Numerous structures within the conducting division do other features as well. The epithelium that the nasal passages, because that example, is necessary to sensing odors, and also the bronchial epithelium that lines the lungs can metabolize part airborne carcinogens.

The Nose and its surrounding Structures

The significant entrance and exit because that the respiratory system is with the nose. When pointing out the nose, that is advantageous to divide it into two significant sections: the outside nose, and the nasal cavity or inner nose.

The exterior nose is composed of the surface and skeletal frameworks that an outcome in the external appearance the the nose and also contribute come its countless functions. The source is the an ar of the nose located in between the eyebrows. The bridge is the component of the sleep that connects the root to the remainder of the nose. The dorsum nasi is the length of the nose. The apex is the pointer of the nose. Top top either next of the apex, the nostrils are created by the alae (singular = ala). An ala is a cartilaginous structure that creates the lateral next of every naris (plural = nares), or nose opening. The philtrum is the concave surface ar that connect the apex of the sleep to the upper lip.

Figure 2. This illustration shows functions of the outside nose (top) and skeletal functions of the nose (bottom).

Underneath the thin skin the the nose are its skeletal features. While the root and bridge that the nose consist that bone, the protruding section of the nose is written of cartilage. Together a result, as soon as looking in ~ a skull, the nose is missing. The sleep bone is among a pair that bones that lies under the root and also bridge the the nose. The sleep bone articulates superiorly v the frontal bone and also laterally through the maxillary bones. Septal cartilage is functional hyaline cartilage connected to the nasal bone, developing the dorsum nasi. The alar cartilage is composed of the apex that the nose; it surrounds the naris.

Figure 3. Top Airway

The nares open right into the sleep cavity, which is separated right into left and also right sections by the nasal septum. The sleep septum is developed anteriorly through a portion of the septal cartilage (the flexible portion you have the right to touch with your fingers) and posteriorly by the perpendicular plate of the ethmoid bone (a cranial bone located simply posterior come the sleep bones) and the thin vomer skeleton (whose name refers to its till shape). Each lateral wall of the sleep cavity has three bony projections, called the superior, middle, and also inferior sleep conchae. The worse conchae are separate bones, vice versa, the superior and also middle conchae are portions of the ethmoid bone. Nasal conchae offer to rise the surface area that the sleep cavity and also to disrupt the circulation of air as it beginning the nose, leading to air come bounce along the epithelium, where it is cleaned and warmed. The conchae and meatuses additionally conserve water and prevent dehydration that the sleep epithelium through trapping water during exhalation. The floor that the sleep cavity is created of the palate. The difficult palate at the anterior an ar of the sleep cavity is composed of bone. The soft palate in ~ the posterior portion of the sleep cavity is composed of muscle tissue. Air exit the sleep cavities via the inner nares and moves into the pharynx.

Several bones that help kind the walls of the sleep cavity have actually air-containing spaces referred to as the paranasal sinuses, which serve to warm and also humidify just arrived air. Sinuses are lined with a mucosa. Every paranasal sinus is called for its associated bone: frontal sinus, maxillary sinus, sphenoidal sinus, and ethmoidal sinus. The sinuses produce mucus and also lighten the weight of the skull.

The nares and anterior part of the nasal cavities space lined v mucous membranes, containing sebaceous glands and hair follicles that serve to protect against the passage of huge debris, such as dirt, v the nasal cavity. One olfactory epithelium offered to recognize odors is discovered deeper in the sleep cavity.

The conchae, meatuses, and paranasal sinuses space lined by respiratory tract epithelium composed of pseudostratified ciliated columnar epithelium. The epithelium consists of goblet cells, one of the specialized, columnar epithelial cells that create mucus to catch debris. The cilia of the respiratory tract epithelium help remove the mucus and also debris from the sleep cavity with a constant beating motion, sweeping materials towards the throat to it is in swallowed. Interestingly, cold wait slows the motion of the cilia, resulting in buildup of mucus that may consequently lead to a runny nose throughout cold weather. This moist epithelium attributes to warm and humidify just arrived air. Capillaries located simply beneath the sleep epithelium heat the air by convection. Serous and also mucus-producing cells likewise secrete the lysozyme enzyme and also proteins dubbed defensins, which have antibacterial properties. Immune cells the patrol the connective organization deep to the respiratory epithelium provide extr protection.

Structure versus function exercise: the sleep cavity

How do nasal conchae add towards the upper respiratory system’s function of preparing air for the respiratory tract division?

The conducting division prepares air by warming, moistening, and cleaning it. The nasal conchae space bumpy structures within the sleep cavity that increase the nasal mucous membrane surface area, maximizing the dimension of that is warm, moist, and sticky surface for air preparation. As air passes through the cavity, the bumpy structures slow-moving air flow and also create turbulence, i beg your pardon stirs the air and increases its contact with the wall surfaces of the nasal passageways wherein it is cleaned and also warmed. The conchae additionally prevent dry of the nasal epithelium by trapping water vapor during exhalation.


The pharynx is a tube formed by skeletal muscle and also lined through mucous membrane that is continuous with that of the sleep cavities. The pharynx is split into three major regions: the nasopharynx, the oropharynx, and also the laryngopharynx.

Figure 5. The pharynx is split into 3 regions: the nasopharynx, the oropharynx, and also the laryngopharynx.

The nasopharynx is flanked by the conchae of the nasal cavity, and it serves only as an airway. In ~ the top of the nasopharynx space the pharyngeal tonsils. A pharyngeal tonsil, additionally called an adenoid, is an aggregate of lymphoid reticular tissue similar to a lymph node the lies in ~ the superior part of the nasopharynx. The duty of the pharyngeal tonsil is not well understood, but it consists of a wealthy supply that lymphocytes and is extended with ciliated epithelium the traps and destroys invading pathogens the enter throughout inhalation. The pharyngeal tonsils are big in children, however interestingly, have tendency to regress v age and also may also disappear. The uvula is a little bulbous, teardrop-shaped structure situated at the apex of the soft palate. Both the uvula and soft palate relocate like a pendulum during swallowing, swinging increase to close off the nasopharynx to stop ingested products from beginning the sleep cavity. In addition, auditory (Eustachian) pipe that attach to each center ear cavity open right into the nasopharynx. This connection is why colds frequently lead come ear infections.

The oropharynx is a passageway the is shared in between the respiratory and digestive systems, and also as such, both air and also food pass with the oropharynx. The oropharynx is bordered superiorly by the nasopharynx and anteriorly by the oral cavity. The fauces is the opening at the connection between the oral cavity and also the oropharynx. Together the nasopharynx i do not care the oropharynx, the epithelium changes from pseudostratified ciliated columnar epithelium to stratified squamous epithelium. The oropharynx contains two distinct sets that tonsils, the palatine and also lingual tonsils. A palatine tonsil is among a pair the structures situated laterally in the oropharynx in the area of the fauces. The lingual tonsil is located at the basic of the tongue. Similar to the pharyngeal tonsil, the palatine and also lingual tonsils room composed of lymphoid tissue, and also trap and also destroy pathogens start the body through the oral or sleep cavities.

The laryngopharynx is worse to the oropharynx and also posterior to the larynx. It proceeds the path for ingested material and air till its worse end, wherein the digestive and also respiratory systems diverge. The stratified squamous epithelium that the oropharynx is consistent with the laryngopharynx. Anteriorly, the laryngopharynx opens into the larynx, vice versa, posteriorly, that enters the esophagus.


The larynx is a cartilaginous framework inferior come the laryngopharynx that connects the pharynx come the trachea and helps regulate the volume that air that enters and leaves the lungs. The structure of the larynx is developed by number of pieces that cartilage. Three large cartilage pieces—the thyroid cartilage (anterior), epiglottis (superior), and also cricoid cartilage (inferior)—form the major structure the the larynx. The thyroid cartilage is the largest piece the cartilage that makes up the larynx. The thyroid cartilage is composed of the laryngeal prominence, or “Adam’s apple,” which tends to be an ext prominent in males. The special cricoid cartilage develops a ring, with a vast posterior an ar and a thinner anterior region. Three smaller, combine cartilages—the arytenoids, corniculates, and cuneiforms—attach to the epiglottis and the vocal cords and also muscle that aid move the vocal cords to create speech.

Figure 6. The larynx extends indigenous the laryngopharynx and the hyoid bone to the trachea.

Figure 7. The true vocal cords and also vestibular wrinkle of the larynx are perceived inferiorly native the laryngopharynx.

The epiglottis, attached come the thyroid cartilage, is a an extremely flexible piece of elastic cartilage the covers the opened of the trachea. Once in the “closed” place (while swallowing), the unattached finish of the epiglottis rests top top the glottis. The glottis is written of the vestibular folds, the true vocal cords, and the room between these folds. A vestibular fold, or false vocal cord, is just one of a pair of folded part of mucous membrane. A true vocal cord is one of the white, membranous wrinkle attached through muscle to the thyroid and also arytenoid cartilages the the larynx on their outer edges. The inner edge of the true vocal cords are free, allowing oscillation to create sound. The dimension of the membranous crease of the true vocal cords differs between individuals, developing voices with various pitch ranges. Wrinkle in males have tendency to be larger than those in females, which produce a depth voice. The plot of swallowing reasons the pharynx and larynx to lift upward, allowing the pharynx to expand and the epiglottis that the larynx come swing downward, close up door the opening to the trachea. These movements create a larger area because that food to pass through, while staying clear of food and also beverages indigenous entering the trachea.

Continuous through the laryngopharynx, the superior part of the larynx is lined v stratified squamous epithelium, transitioning into pseudostratified ciliated columnar epithelium that consists of goblet cells. This devoted epithelium produces rubber to trap debris and also pathogens as they enter the trachea. The cilia to win the mucus upward towards the laryngopharynx, where it deserve to be swallowed under the esophagus.

The mucociliary escalator

The mucociliary escalator operation from the bronchi to the larynx, and serves to efficiently clean, moisten, and warm incoming air. It is composed of pseudostratified columnar epithelium that has tiny hairs called cilia on your apical surface. Additionally included in this epithelial great are dedicated mucus-producing cells referred to as goblet cells. Similar to the sleep cavity, the rubber serves come moisten air, if trapping pathogens and debris that is in the air. The mucus sits on top of the cilia, i m sorry continually to win upwards, carrying the mucus and also any debris the it traps away from the lungs. This cleaning procedure also serves to get rid of bacteria native the air, in order to protecting the lungs from infection.

Figure 8. Mucociliary escalator: Debris is trapped in mucus that is make by goblet cells. The mucus and also debris space brushed upwards, far from the lungs, thereby ensuring that air is clean before entry right into the lungs.


The trachea (windpipe) extends native the larynx towards the lungs. The trachea is created by 16 come 20 stacked, C-shaped piece of hyaline cartilage that are associated by dense connective tissue. The trachealis muscle and elastic connective tissue together form the fibroelastic membrane, a functional membrane that closes the posterior surface of the trachea, connecting the C-shaped cartilages. The fibroelastic membrane allows the trachea come stretch and also expand slightly throughout inhalation and also exhalation, vice versa, the rings of cartilage carry out structural support and prevent the trachea from collapsing. In addition, the trachealis muscle can be contract to force air with the trachea during exhalation. The trachea is lined v pseudostratified ciliated columnar epithelium, i m sorry is constant with the larynx. The esophagus boundaries the trachea posteriorly.

Bronchial Tree

The trachea branches right into the right and also left main bronchi in ~ the carina. These bronchi are additionally lined by pseudostratified ciliated columnar epithelium include mucus-producing goblet cells. The carina is a increased structure that contains committed nervous organization that root cause violent coughing if a international body, such as food, is present. Ring of cartilage, similar to those that the trachea, support the structure of the bronchi and prevent your collapse. The primary bronchi get in the lungs at the hilum, a concave region where blood vessels, lymphatic vessels, and nerves additionally enter the lungs. The bronchi proceed to branch into bronchial a tree. A bronchial tree (or respiratory tree) is the cumulative term provided for these multiple-branched bronchi. The main role of the bronchi, like other conducting department structures, is to administer a passageway for air to relocate into and out of each lung. In addition, the mucous membrane trap debris and pathogens.

A bronchiole branches from the tertiary bronchi. Bronchioles, which are about 1 mm in diameter, additional branch until they become the tiny terminal bronchioles, which result in the frameworks of gas exchange. There are much more than 1000 terminal bronchioles in each lung. The muscular wall surfaces of the bronchioles carry out not save on computer cartilage choose those of the bronchi. This muscular wall surface can readjust the dimension of the tubing to boost or to decrease airflow with the tube.

Respiratory Division

In comparison to the conducting division, the respiratory division contains structures that are directly connected in gas exchange. The respiratory division starts where the terminal bronchioles sign up with a respiratory bronchiole, the smallest kind of bronchiole, which then leads to an alveolar duct, opening into a cluster of alveoli.

Figure 10. Bronchioles lead to alveolar bag in the respiratory tract division, whereby gas exchange occurs.


An alveolar duct is a tube created of smooth muscle and also connective tissue, i m sorry opens right into a cluster of alveoli. Alveoli are small, grape-like sacs that are attached to the alveolar ducts.

An alveolar sac is a cluster of numerous individual alveoli that are responsible for gas exchange. An alveolus is approximately 200 mm in diameter with elastic walls that enable the alveolus to stretch during air intake, which greatly increases the surface area easily accessible for gas exchange. Alveoli are connected to their next-door neighbors by alveolar pores, which assist maintain same air pressure throughout the alveoli and lung.

The alveolar wall consists of three major cell types: form I alveolar cells, form II alveolar cells, and alveolar macrophages. A type ns alveolar cell is a squamous epithelial cabinet of the alveoli, i beg your pardon constitute as much as 97 percent of the alveolar surface ar area. Type 1 alveolar cell are really thin- only about 25 nm thick and also are extremely permeable to gases. A type II alveolar cell is interspersed amongst the kind I cells and secretes pulmonary surfactant, a substance composed of phospholipids and proteins that reduces the surface stress of the alveoli, staying clear of these small air sacs from collapsing throughout expiration. Roaming roughly the alveolar wall surface is the alveolar macrophage, a phagocytic cell of the immune system that removes debris and pathogens that have actually reached the alveoli.

Respiratory membrane

The respiratory membrane (Figure 10a) is the framework gasses pass through to move in between the alveoli in the lungs and the blood. That is a an extremely thin membrane consisted of of alveolar wall, and a capillary wall. If you recall, a capillary wall surface is consisted of of tunica intima, i m sorry is a solitary layer that endothelial cells relaxing on a basement membrane. The alveolar wall is a basic squamous epithelium formed by kind I alveolar cell is attached to a thin, elastic basement membrane. Taken together, the respiratory tract membrane is comprised of 1) an alveolar wall made mainly from a solitary layer of kind I alveolar cells, 2) a capillary wall made from a solitary layer the endothelial cells, and between them, 3) a shared basement membrane. Due to the fact that both kind I alveolar cells and also endothelial cells room squamous in shape and quite thin, the respiratory tract membrane is only approximately 0.5 mm thick, and also as such, permits gasses to quickly cross. The respiratory membrane permits gases to cross by an easy diffusion, permitting oxygen to be choose up through the blood for transport and CO2 to it is in released right into the air of the alveoli.

Diseases that the respiratory tract System: Asthma

Asthma is usual condition that affects the lungs in both adults and also children. About 8.2 percent of adult (18.7 million) and 9.4 percent of youngsters (7 million) in the United claims suffer indigenous asthma. In addition, asthma is the most frequent reason of hospitalization in children.

Asthma is a chronic disease characterized by inflammation and edema that the airway, and also bronchospasms (that is, constriction that the bronchioles), which have the right to inhibit waiting from entering the lungs. In addition, too much mucus secretion have the right to occur, which additional contributes to airway occlusion. Cell of the immune system, such as eosinophils and mononuclear cells, may additionally be associated in infiltrating the walls of the bronchi and bronchioles.

Bronchospasms happen periodically and lead come an “asthma attack.” An strike may be prompted by environmental factors such together dust, pollen, pets hair, or dander, transforms in the weather, mold, tobacco smoke, and respiratory infections, or by exercise and also stress.

Figure 11. (a) common lung tissue does not have the qualities of lung tissue during (b) an asthma attack, which incorporate thickened mucosa, enhanced mucus-producing goblet cells, and eosinophil infiltrates.

Symptoms of an asthma assault involve coughing, shortness of breath, wheezing, and tightness the the chest. Symptom of a severe asthma assault that requires prompt medical attention would include challenge breathing that results in blue (cyanotic) lips or face, confusion, drowsiness, a quick pulse, sweating, and severe anxiety. The severity the the condition, frequency the attacks, and also identified triggers influence the kind of medication that an individual might require. Longer-term treatments are used for those with more severe asthma. Short-term, fast-acting drugs that are supplied to act an asthma strike are frequently administered via an inhaler. Because that young children or individuals who have difficulty using an inhaler, asthma medications can be administered via a nebulizer.

In numerous cases, the underlying cause of the condition is unknown. However, recent research has actually demonstrated that certain viruses, together as human being rhinovirus C (HRVC), and also the bacteria Mycoplasma pneumoniae and Chlamydia pneumoniae that are contracted in infancy or beforehand childhood, may contribute to the advance of many situations of asthma.

Practice Question

Watch this video to learn an ext about what happens throughout an asthma attack.What room the three alters that take place inside the airways during an asthma attack?

Inflammation and also the manufacturing of a special mucus; constriction that the airway muscles, or bronchospasm; and also an boosted sensitivity come allergens.

Chapter Review

The respiratory device is responsible because that obtaining oxygen and getting rid the carbon dioxide, and aiding in decided production and in sensing odors. Indigenous a sensible perspective, the respiratory system deserve to be separated into two major areas: the conducting division and also the respiratory division. The conducting division is composed of all of the frameworks that carry out passageways because that air to travel into and also out the the lungs: the sleep cavity, pharynx, trachea, bronchi, and also most bronchioles. The sleep passages save on computer the conchae and also meatuses that broaden the surface area the the cavity, which help to warm and humidify just arrive air, when removing debris and pathogens. The pharynx is written of three major sections: the nasopharynx, i m sorry is consistent with the nasal cavity; the oropharynx, which boundaries the nasopharynx and the dental cavity; and also the laryngopharynx, which boundaries the oropharynx, trachea, and esophagus. The respiratory division consists of the frameworks of the lung that space directly connected in gas exchange: the terminal bronchioles and also alveoli.

The lining that the conducting division is composed greatly of pseudostratified ciliated columnar epithelium v goblet cells. The rubber traps pathogens and also debris, vice versa, beating cilia relocate the rubber superiorly towards the throat, whereby it is swallowed. As the bronchioles end up being smaller and smaller, and nearer the alveoli, the epithelium thins and also is an easy squamous epithelium in the alveoli. The endothelium that the neighboring capillaries, together with the alveolar epithelium, develops the respiratory membrane. This is a blood-air barrier through i beg your pardon gas exchange wake up by simple diffusion.

Self Check

Answer the question(s) below to see exactly how well you understand the topics spanned in the previous section.

Critical Thinking Questions

Describe the three areas of the pharynx and their functions.If a human sustains one injury to the epiglottis, what would certainly be the physiological result?Compare and contrast the conducting and also respiratory divisions.
The pharynx has actually three significant regions. The an initial region is the nasopharynx, i m sorry is linked to the posterior sleep cavity and functions as an airway. The second an ar is the oropharynx, i beg your pardon is continuous with the nasopharynx and is linked to the oral cavity in ~ the fauces. The laryngopharynx is associated to the oropharynx and the esophagus and trachea. Both the oropharynx and also laryngopharynx space passageways because that air and also food and drink.The epiglottis is a an ar of the larynx that is important throughout the swallowing the food or drink. As a person swallows, the pharynx move upward and also the epiglottis closes end the trachea, staying clear of food or drink indigenous entering the trachea. If a person’s epiglottis to be injured, this mechanism would be impaired. Together a result, the human being may have problems with food or drink beginning the trachea, and also possibly, the lungs. Over time, this may cause infections such together pneumonia to set in.The conducting division the the respiratory tract system has the organs and structures that space not directly connected in gas exchange, however perform other duties such as giving a passageway for air, trapping and removing debris and also pathogens, and also warming and also humidifying incoming air. Such structures encompass the sleep cavity, pharynx, larynx, trachea, and most the the bronchial tree. The respiratory zone includes all the organs and structures that are directly associated in gas exchange, including the respiratory bronchioles, alveolar ducts, and also alveoli.

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ala: (plural = alae) small, flaring framework of a nostril that forms the lateral next of the nares

alar cartilage: cartilage that supports the apex that the nose and helps form the nares; it is connected to the septal cartilage and also connective organization of the alae

alveolar duct: small tube the leads from the terminal bronchiole to the respiratory bronchiole and is the allude of attachment for alveoli

alveolar macrophage: immune mechanism cell the the alveolus that removes debris and also pathogens

alveolar pore: opening that permits airflow in between neighboring alveoli

alveolar sac: cluster that alveoli

alveolus: small, grape-like sac the performs gas exchange in the lungs

apex: tip the the external nose

bronchial tree: collective surname for the multiple branches of the bronchi and bronchioles of the respiratory system

bridge: portion the the external nose the lies in the area the the nasal bones

bronchiole: branch of bronchi that are 1 mm or much less in diameter and also terminate at alveolar sacs

bronchus: tube linked to the trachea the branches into plenty of subsidiaries and also provides a passageway because that air to enter and also leave the lungs

conducting division: region the the respiratory device that contains the organs and also structures that carry out passageways for air and are not directly connected in gas exchange

cricoid cartilage: portion that the larynx composed of a ring that cartilage with a broad posterior region and a diluent anterior region; attached come the esophagus

dorsum nasi: intermediate portion of the exterior nose that connects the leg to the apex and also is sustained by the nasal bone

epiglottis: leaf-shaped item of elastic cartilage the is a portion of the larynx that swings come close the trachea throughout swallowing

external nose: region the the nose that is quickly visible to others

fauces: portion of the posterior dental cavity that connects the dental cavity come the oropharynx

fibroelastic membrane: specialized membrane the connects the end of the C-shape cartilage in the trachea; contains smooth muscle fibers

glottis: opening in between the vocal folds through which air overcome when creating speech

laryngeal prominence: region whereby the 2 lamina of the thyroid cartilage join, developing a protrusion well-known as “Adam’s apple”

laryngopharynx: portion the the pharynx bordered through the oropharynx superiorly and also esophagus and also trachea inferiorly; serves as a course for both air and also food

larynx: cartilaginous framework that to produce the voice, avoids food and beverages from entering the trachea, and regulates the volume of air that enters and also leaves the lungs

lingual tonsil: lymphoid tissue situated at the base of the tongue

meatus: one of 3 recesses (superior, middle, and also inferior) in the sleep cavity attached come the conchae that rise the surface ar area that the sleep cavity

naris: (plural = nares) opened of the nostrils

nasal bone: bone the the skull the lies under the root and bridge of the nose and also is linked to the frontal and also maxillary bones

nasal septum: wall written of bone and cartilage the separates the left and also right nasal cavities

nasopharynx: portion of the pharynx flanked by the conchae and also oropharynx that serves as an airway

oropharynx: portion the the pharynx flanked through the nasopharynx, oral cavity, and laryngopharynx the is a passageway for both air and also food

palatine tonsil: one the the paired structures composed the lymphoid tissue situated anterior to the uvula at the roof the isthmus of the fauces

paranasal sinus: one that the cavities within the skull the is connected to the conchae that serve to warm and also humidify just arrive air, create mucus, and lighten the load of the skull; consists of frontal, maxillary, sphenoidal, and also ethmoidal sinuses

pharyngeal tonsil: structure created of lymphoid tissue situated in the nasopharynx

pharynx: region the the conducting division that forms a pipe of skeleton muscle lined through respiratory epithelium; located in between the sleep conchae and also the esophagus and trachea

philtrum: concave surface ar of the face that connects the apex the the nose to the top lip

pulmonary surfactant: substance created of phospholipids and proteins the reduces the surface anxiety of the alveoli; made by kind II alveolar cells

respiratory bronchiole: specific form of bronchiole that leads come alveolar sacs

respiratory epithelium: ciliated lining of much of the conducting division the is dedicated to remove debris and also pathogens, and produce mucus

respiratory membrane: alveolar and capillary wall surface together, which kind an air-blood barrier that facilitates the basic diffusion of gases

respiratory division: includes structures of the respiratory device that space directly connected in gas exchange

root: region that the external nose in between the eyebrows

thyroid cartilage: largest piece of cartilage that renders up the larynx and also consists of 2 lamina

trachea: tube created of cartilaginous rings and supporting tissue that associate the lung bronchi and the larynx; gives a path for air to enter and also exit the lung

trachealis muscle: smooth muscle located in the fibroelastic membrane that the trachea

true vocal cord: one that the pair that folded, white membrane that have a complimentary inner edge the oscillates as air passes v to create sound

type ns alveolar cell: squamous epithelial cell that room the major cell kind in the alveolar wall; extremely permeable to gases

type II alveolar cell: cuboidal epithelial cells that room the minor cell kind in the alveolar wall; secrete pulmonary surfactant

vestibular fold: part the the folded an ar of the glottis written of mucous membrane; supports the epiglottis during swallowing


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