BRS CHAPTER 15 Respiratory

What type of lymphoid tissue lies below the respiratory epithelia of the nasopharyx?

The lamina propria of the nasopharynx, located beneath the respiratory epithelium, contains mucous and serous glands as well as an abundance of lymphoid tissue known as Waldeyer ring, including the pharyngeal tonsil. When the pharyngeal tonsil is inflamed, it is called an adenoid.

These cells are filled with large secretory granules, containing mucinogen droplets and line the respiratory mucosa.

Mature goblet cells are goblet shaped and are filled with large secretory granules, containing mucinogen droplets, which are secreted onto the epithelial surface to trap inhaled particles.

The nasal cavity is subdivided into?

Nasal cavity. The nasal cavity is subdivided by the median nasal septum into right and left nasal cavities, each leading to the paranasal sinuses, thus providing a large surface area for filtering, moistening, and warming the inspired air.

What type of neurons are olfactory cells?

Olfactory cells are bipolar nerve cells characterized by a bulbous apical projection (olfactory vesicle) from which several modified cilia extend.

What type of cilia are present in the olfactory region?

Olfactory cilia (olfactory hairs) (a) are very long, non motile cilia that extend over the surface of the olfactory epithelium. Their proximal third contains a typical 9 + 2 axoneme pattern, but their distal two thirds are composed of nine peripheral singlet microtubules surrounding a central pair of microtubules. (b) act as receptors for odor.

Cells present in the olfactory epithelium?

Olfactory epithelium a. Overview (1) The olfactory epithelium is located in the roof of the nasal cavity, on either side of the nasal septum and on the superior nasal conchae. (2) It is a tall, pseudostratified columnar epithelium consisting of olfactory cells, supporting (sustentacular) cells, and basal cells (stem cells).

What lies on the lateral walls of the nasopharynx?

Opening into the right and left lateral walls of the nasopharynx are the auditory tubes (Eustachian tubes), each arising from its respective middle ear cavity.

Parasympathetic stimulation of autonomic smooth muscle fibers of bronchi results in?

Parasympathetic stimulation causes contraction of pulmonary smooth muscle.

Primary and terminal bronchioles lack this feature

Primary and terminal bronchioles lack glands in their submucosa. Their walls contain smooth muscle rather than cartilage plates.

What carries blood to the lungs to be oxygenated?

Pulmonary artery 1. The pulmonary artery carries blood to the lungs to be oxygenated. 2. It enters the root of each lung and extends branches along the divisions of the bronchial tree. 3. It enters lung lobules, where its branches follow the bronchioles.

Structure-Pulmonary surfactant

Pulmonary surfactant consists of (dipalmitoylphosphatidylcholine, phospholipids, the) four apolipoproteins, surfactant-associated proteins (known as SP-A, SP-8, SP-C, and SP-D), and cholesterol. It forms tubular myelin (a network configuration) when it is first released from lamellar bodies; it then spreads to produce a monomolecular film over the alveolar surface, (forming a lower aqueous phase and a superficial lipid phase.)

What run in the intersegmental connective tissue?

Pulmonary veins 1. In lung lobules, pulmonary veins run in the intersegmental connective tissue, separated from the arteries. 2. After leaving the lobules, the pulmonary veins come close to divisions of the bronchial tree and run parallel to branches of the pulmonary artery as they accompany bronchi to the root of the lung.

Respiratory mucosa ciliated cells function to?

RespMucosa Ciliated cells (a) have long, actively motile cilia that beat toward the mouth. (b) move inhaled particulate matter trapped in mucus toward the oropharynx, thus protecting the delicate lung tissue from damage. (c) also possess microvilli.

lined by a simple cuboidal epithelium that abruptly changes to a simple epithelium

Respiratory bronchioles 1. The respiratory bronchioles mark the transition from the conducting to the respiratory portion of the respiratory system. 2. They are lined by a simple cuboidal epithelium that contains mostly club cells and some ciliated cells, except where their walls are interrupted by alveoli, the sites where gas exchange occurs and where the lining abruptly changes to a simple epithelium composed of highly attenuated squamous cells.

Oat cell?!

Small cell (oat cell) carcinoma is a highly aggressive carcinoma of bronchial origin whose incidence is greatly increased in smokers. It has a poor prognosis.

Brush cell act to replace recently blank ?

Small granule-mucous cells (brush cells) (a) contain varying numbers of small mucous granules. (b) are sometimes called brush cells because of their many uniform microvilli. (c) actively divide and often replace recently desquamated cells. (d) may represent goblet cells after they have secreted their mucinogen.

This cancer uses the respiratory epithelium to change to a stratified squamous epithelium (a metaplastic change).

Squamous cell carcinoma typically a rises in the bronchi, where cigarette smoking causes the respiratory epithelium to change to a stratified squamous epithelium (a metaplastic change). Then, a disorderly proliferation of cells showing great variability in nuclear size and shape occurs in the epithelium (dysplasia), followed by atypical changes that result in a carcinoma (a malignant neoplasm).

What are supporting cells found in the olfactory epithelia?

Supporting (sustentacular) cells (a) possess nuclei that are more apically located than those of the other two cell types. (b) have many microvilli and a prominent terminalweb of filaments.

Function-Pulmonary surfactant.

Surfactant reduces the surface tension at the air-liquid interface of the alveolar surface(, permitting the alveoli to expand easily during inspiration and preventing alveolar collapse during expiration. Additionally, surfactant reduces fluid accumulation in the alveoli.) (SP-A and SP-D,) apolipoproteins of the surfactant, participate in innate immunity by binding to bacterial and viral surfaces, (and in that fashion) opsonizing them. The opsonized microorganisms are recognized and phagocytosed by macrophages (dust cells of the lung.)

Sympathetic stimulation of autonomic smooth muscle fibers of bronchi results in?

Sympathetic stimulation causes relaxation of pulmonary smooth muscle and can be mimicked by certain drugs that cause dilation of bronchi and bronchioles.

Terminal bronchioles are lined by what cells?

Terminal bronchioles are the most distal part of the conducting portion of the respiratory system. They have a diameter of less than 0.5 mm. They are lined by a simple cuboidal epithelium that contains mostly club cells formerly known as Clara cells, some ciliated cells, and no goblet cells.

The adventitia of the trachea contains?

The adventitia contains C-shaped hyaline cartilages and forms the outermost layer of the trachea.

The very thick layer underlying the epithelium?

The basement membrane is a very thick layer underlying the epithelium.

How do dust cells protect the lungs from foreign pathogens and material?

(3) migrate to the bronchioles after filling with debris. From there, they are carried via ciliary action to the upper airways, eventually reaching the oropharynx, where they are either swallowed or expectorated. (4) may also exit by migrating into the interstitium and leaving via lymphatic vessels.

What contains a single primary bronchiole, which enters at the apex and branches to form five to seven terminal bronchioles?

(Lung lobules vary greatly in size and shape, but )each has an apex directed toward the pulmonary hilum and a wider base directed outward. Each lobule contains a single primary bronchiole, which enters at the apex and branches to form (five to seven) terminal bronchioles. The terminal bronchioles in turn divide, ultimately giving rise to alveoli at the base of the lobule.

Primary bronchioles have the divide into? And have the following cells?

(a. Primary bronchioles have a diameter of 1 mm or less.) b. They are lined by epithelium that varies from ciliated columnar with goblet cells in the larger airways to ciliated cuboidal with Clara cells in the smaller passages. c. They divide to form several terminal bronchioles after entering the pulmonary lobules.

Turbinate bones?

(turbinate bones). Their structure and placement within the nasal cavity divide it into separate regions, thereby introducing turbulence to the air flow. Since they are covered by respiratory epithelium, their presence increases the surface area for warming, filtering, and moistening the inspired air

They are the most distal portion of the respiratory system to contain smooth muscle cells, which rim the openings of adjacent alveoli and which often appear as knobs in histological sections.

Alveolar ducts 1. Alveolar ducts are linear passageways continuous with the respiratory bronchioles. 2. Their walls consist of adjacent alveoli, which are separated from one another only by an interalveolar septum. 3. They are the most distal portion of the respiratory system to contain smooth muscle cells, which rim the openings of adjacent alveoli and which often appear as knobs in histological sections. 4. Alveolar ducts are lined by type II pneumocytes and the highly attenuated simple squamous epithelium of type I pneumocytes.

alveolar phagocytes

Alveolar macrophages (alveolar phagocytes; dust cells) (1) are the principal mononuclear phagocytes of the alveolar surface. (2) remove inhaled dust, bacteria, and other particulate matter trapped in the pulmonary surfactant, thus providing a vital line of defense in the lungs.

Expanded outpouchings of numerous alveoli

Alveolar sacs are expanded outpouchings of numerous alveoli at the distal ends of alveolar ducts

pouch-like evaginations in walls of respiratory bronchioles

Alveoli are pouch-like evaginations about 200 f.Lm in diameter in the walls of respiratory bronchioles, in alveolar ducts, and in alveolar sacs.

What are basal cells?

Basal cells (a) are short cells that rest on the basal lamina, but do not extend to the lumen; thus, this epithelium is pseudostratified. (b) are stem cells that are able to divide and replace the other cell types.

What is the purpose of Basal cells?

Basal cells (a) rest on the basal lamina but do not extend to the surface. (b) form an incomplete layer of cells. (c) are believed to be regenerative for all three cell types.

This permits the diffusion of gases between the alveolar airspace and the blood.

Blood-gas barrier. The blood-gas barrier permits the diffusion of gases between the alveolar airspace and the blood. Oxygen passes from the alveolus into the capillary, and carbon dioxide passes from the capillary blood into the alveolus.

What type of gland is a Bowman gland?

Bowman glands (serous glands) produce a thin, watery secretion that is released onto the olfactory epithelial surface via narrow ducts. Odorous substances dissolved in this watery material are detected by the olfactory cilia. The secretion also flushes the epithelial surface, preparing the receptors to receive new odorous stimuli.

What provide nutrients to and remove wastes from the nonrespiratory portions of the lung?

Bronchial arteries and veins 1. Bronchial arteries and veins provide nutrients to and remove wastes from the nonrespiratory portions of the lung (bronchi, bronchioles, interstitium, and pleura). 2. They follow the branching pattern of the bronchial tree and form anastomoses with the pulmonary vessels near capillary beds.

Carbon monoxide poisoning

Carbon monoxide is an odorless, taste less gas that binds to hemoglobin in red blood cells with a greater affinity than does oxygen. It is produced when ever fuel-burning appliances are used, which explains the importance of using carbon monoxide detectors.(Individuals exposed to carbon monoxide are often unaware of the symptoms it may cause (such as nausea, headache, and sleepiness). Death may occur as the gas replaces oxygen in red blood cells of the lung and blocks the delivery of oxygen to tissues of the body.) Treatment consists of exposing the patient to 100% oxygen (sometimes in a hyperbaric chamber) until oxygen displaces the carbon monoxide and recovery occurs.

Inferior to the vocal cords, the lining epithelium changes to?

Contraction of the laryngeal muscles changes the size of the opening between the vocal cords, which affects the pitch of the sounds caused by air passing through the larynx. b. Inferior to the vocal cords, the lining epithelium changes to respiratory epithelium, which lines air passages down through the trachea and intrapulmonary bronchi.

The type of connective tissue is located between adjacent C-rings?

Dense fibroelastic connective tissue is located between adjacent C-rings, permitting elongation of the trachea during inhalation.

These cells are also known as small granule cells, amine precursor uptake and decarboxylation (APUD cells), or enteroendocrine cells.

Diffuse neuroendocrine cells contain many small granules concentrated in their basal cytoplasm. (c) synthesize different polypeptide hormones and serotonin, which often exert a local effect on nearby cells and structures (paracrine regulation). (The peptide hormones may also enter the bloodstream and have an endocrine effect on distant cells and structures.)

Spontaneous pneumothorax

The collection of gas in the pleural cavity, the potential space between the visceral and parietal pleurae. It causes sudden sharp, severe chest pain on the same side as the affected lung and leads to shortness of breath. The condition occurs most often in young people who have no known underlying pulmonary disease. (But computed to mographyscans typically reveal blebs near the lung surface that rupture, allowing gas to invade the pleural space and causing the lung to collapse either partially or completely. Am in or lung collapse will often resolve on its own, but when the pneumothorax is larger, a needle or tube is usually inserted between the ribs to remove the gas over a period of a few days, which permits the lung to reinflate.)

What features are present in the respiratory system?

The components of the respiratory system possess characteristic lining epithelia, supporting structures, glands, and other features.

Asbestosis- is a pulmonary disease caused by inhaling asbestos fibers (used in insulation materials, tiles, etc.)

The fibers deposit in the alveolar ducts and alveoli. The smaller fibers are phagocytosed by macrophages, but the larger ones penetrate the lung interstitium. (3. Activated macrophages release inflammatory mediators, which )lead to interstitial pulmonary fibrosis in the walls of respiratory bronchioles, alveolar ducts, and alveoli. (4. Asbestos bodies, fibers 10 to 50m long encrusted with beads of protein, form in the interstitium and alveolar spaces. The) asbestos bodies stain strongly for iron because of the hemoglobin protein released from small hemorrhages that accompany the fibrosis.

Club cells are vital as they serve these functions:

Divide, and some of them differentiate to form ciliated and nonciliated cells. Secrete a surfactant-like material that reduces alveolar surface tension (preventing the collapse of alveoli). Produce club cell secretory protein that protects the respiratory epithelium. They metabolize airborne toxins, carried out by cytochrome P450 (enzymes in their abundant smooth endoplasmic reticulum (SER).)

Emphysema

Emphysema results from destruction of alveolar walls and formation of large cyst-like sacs(, reducing the surface area available for gas exchange.) 2. It is marked by decreased elasticity of the lungs, which are unable to recoil adequately during expiration. In time, the lungs expand and enlarge the thoracic cavity (barrel chest). 3. Emphysema is associated with exposure to cigarette smoke and other substances that inhibit a1-antitrypsin, a protein that normally protects the lungs from the action of elastase produced by alveolar macrophages. (4. It can be a hereditary condition resulting from a defective a1-antitrypsin. In such cases, gene therapy with recombinant a1-antitrypsin is being used in an effort to correct the problem, and it has recently been successful in boosting the availability of this protective protein.)

infant respiratory distress syndrome

Hyaline membrane disease 1. frequently observed in premature infants (<28 weeks' gestational age) who lack adequate amounts of pulmonary surfactant. 2. It is characterized by labored breathing, which results from difficulty expanding the alveoli because of a high alveolar surface tension. (3. If detected before birth, hyaline membrane disease can often be prevented by prolonging pregnancy and sometimes by administering glucocorticoids to the expectant mother a few days prior to delivery to help induce the synthesis of surfactant.)

These divide many times and give rise to lobar and segmental bronchi.

Intrapulmonary bronchi arise from subdivisions of the primary bronchi upon entering the hilum of the lung. It is at this level that the cartilaginous rings of the bronchi are replaced with plates of irregularly shaped hyaline cartilage. (They divide many times and give rise to lobar and segmental bronchi.)

What does the lamina propria of the olfactory epithelium house?

It has a lamina propria that contains many veins and unmyelinated nerves, and houses Bowman glands.

lnteralveolar septum

The interalveolar septum is the wall, or partition, between two adjacent alveoli. It is bounded on its outer surfaces by the extremely thin, simple, squamous epithelium lining the alveoli. It contains many elastic and reticular fibers in its thicker regions. It houses continuous capillaries (in its central (interior)region.)

The lamina propria contains special fibers that are?

The lamina propria is a thin layer of connective tissue that lies beneath the basement membrane. It contains longitudinal elastic fibers separating the lamina propria from the submucosa.

Nostrils are called?

The nares are the nostrils; their outer portions are lined by thin skin. They open into the vestibule.

What is the lining of the nasopharynx?

The nasopharynx, the posterior continuation of the nasal cavities, becomes continuous with the oropharynx at the level of the soft palate. 2. It is lined by respiratory epithelium, whereas the oropharynx and laryngopharynx are lined by stratified squamous nonkeratinized epithelium.

True or False: Axons are also present in the thicker parts of the interalveolar septa.

The pulmonary nerve supply consists primarily of autonomic fibers to the smooth muscle of bronchi and bronchioles. Axons are also present in the thicker parts of the interalveolar septa.

The respiratory system can be functionally classified into two major subdivisions:

The respiratory system can be functionally classified into two major subdivisions : a conducting portion, consisting of airways that deliver air to the lungs, and a respiratory portion, consisting of structures within the lungs in which oxygen in the inspired air is exchanged for carbon dioxide in the blood.

Respiratory system includes?

The respiratory system includes the lungs and a series of airways that connect the lungs to the external environment.

What is the submucosa?

The submucosa is a connective tissue layer containing many seromucous glands.

List the layers of the blood gas barrier?

The thinnest regions of the barrier are 0.2 11m or less in thickness and consist of the following layers: (a) Type I pneumocytes and layer of surfactant lining the alveolar airspace (b) Fused basal laminae of type I pneumocytes and capillary endothelial cells (c) Endothelium of the continuous capillaries within the interalveolar septum (2) Thicker regions of the barrier measure as much as 0.5 1-m across and have an interstitial area interposed between the two unfused basal laminae.

C-shaped hyaline cartilages (C-rings), whose open?

The trachea, the largest conducting section of the respiratory system, bifurcates into the right and left primary bronchi, each of which enters the hilum of the lung on its side. a. The walls of these structures are supported by C-shaped hyaline cartilages (C-rings), whose open ends face posteriorly. Smooth muscle (trachealis muscle in the trachea) extends between the open ends of these cartilages.

Describe the lamina propria of the vestibule, and features?

The vestibule contains vibrissae (thick, short hairs), which filter large particles from the inspired air. b. It has a richly vascularized lamina propria (many venous plexuses) and contains seromucous glands. c. Each nasal cavity contains bony shelves that originate from the lateral nasal wall and project into the nasal cavity. These are the superior, middle, and inferior conchae.

First portion of the nasal cavity?

The vestibule is the first portion of the nasal cavity, where the epithelial lining becomes nonkeratinized. Posteriorly, the lining changes to respiratory epithelium (pseudostratified ciliated columnar epithelium with goblet cells).

Type of epithelia on vocal cords?

The vocal cords consist of skeletal muscle (the vocalis muscle), the vocal ligament (formed by a band of elastic fibers), and a covering of stratified squamous nonkeratinized epithelium.

What are alveoli lined by?

They are lined by a highly attenuated simple squamous epithelium composed of type I and type II pneumocytes.

What are intrapulmonary bronchi lined by?

They are lined by respiratory epithelium. Spiraling smooth muscle bundles separate the lamina propria from the submucosa, which contains seromucous glands.

Pores of Kohn?

They are separated from each other by interalveolar septa that may contain one or more alveolar pores (pores of Kohn). These pores permit equalization of pressure between alveoli.

The respiratory tract in order?

This portion of the respiratory system includes the nose, nasopharynx, larynx, trachea, bronchi, and bronchioles of decreasing diameters, including and ending at the terminal bronchioles. These structures warm, moisten, and filter the air before it reaches the respiratory components, where gas exchange occurs.

Lung cancers that are increased in smokers are?

Two types of lung cancer that are increased in smokers include squamous cell carcinoma and small cell (oat cell) carcinoma.

These cells cover about 95% of the alveolar surface and form part of the blood-gas barrier where exchange of oxygen and carbon dioxide occurs. They also form tight junctions with adjacent cells.

Type I pneumocytes (type I alveolar cells) (1 cover about 95% of the alveolar surface and form part of the blood-gas barrier where exchange of oxygen and carbon dioxide occurs.) (2) have an extremely thin cytoplasm that may be less than 80 nm thick. (3) form tight junctions with adjacent cells. (4) may have phagocytic capabilities. (5) are not able to divide.

These cells bulge into the alveolus and have a free surface that contains short microvilli around their peripheral borders. These cells are able to divide and regenerate both types of alveolar pneumocytes.

Type II pneumocytes (type II alveolar cells; great alveolar cells; granular pneumocytes; septal cells) (1) are cuboidal and are most often found near septal intersections. (2 bulge into the alveolus and have a free surface that contains short microvilli around their peripheral borders.) (3) are able to divide and regenerate both types of alveolar pneumocytes. (4) form tight junctions with adjacent cells. (5) synthesize pulmonary surfactant, which is stored in cytoplasmic lamellar bodies.

false vocal cords

Vestibular folds (false vocal cords) lie superior to the vocal cords. a. These folds of loose connective tissue contain glands, lymphoid aggregations, and fat cells. b. They are covered by stratified squamous non keratinized epithelium.

Asthma

Widespread constriction of smooth muscle in the bronchioles, causing a decrease in their diameter. (It is associated with extremely) difficult expiration of air, accumulation of mucus in the passageways, and infiltration of inflammatory cells. It is often treated with drugs, such as albuterol, that act to relax the bronchiolar smooth muscle cells (and dilate the passageways and/)or with corticosteroids, which are anti-inflammatory. (Recent studies have demon strated that there are taste receptors on the smooth muscle cells of bronchioles of the lungs that respond to bitter tastes, and when stimulated by a bitter tastant, they cause bronchiolar smooth muscles to relax and the bronchioles to open to 90% of their normal volume. Current work is proceeding to develop aerosolized substances that can be used to stimulate these receptors.)

The larynx? Types of cartilage?

a. The larynx connects the pharynx with the trachea. It functions to produce sounds and close the air passage during swallowing. b. The wall of the larynx is supported by hyaline cartilages (thyroid, cricoid, and lower part of arytenoids) and elastic cartilages (epiglottis, corniculate, and tips of arytenoids). c. The laryngeal wall also possesses skeletal muscle, connective tissue, and glands.

What do the pores of kohn allow for?

b. They have thin walls, across which oxygen and carbon dioxide diffuse between the air and the blood. They are separated from each other by interalveolar septa that may contain one or more alveolar pores (pores of Kohn). These pores permit equalization of pressure between alveoli.

Alveoli are supported by the following fibers.

d. They are rimmed by elastic fibers at their openings (except in alveolar ducts, where they are rimmed by smooth muscle cells) and are supported by many reticular fibers in their walls.