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34 Cards in this Set
- Front
- Back
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These two respiratory processes usually co-exist and are lumped together under COPD.
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Emphysema and chronic bronchitis
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What does an alveolar sac consist of?
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2-3 alveoli
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What does an acinus consist of?
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A single terminal bronchiole, its respiratory bronchioles, alveolar ducts, and alveolar sacs
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What defines emphysema?
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Permanent enlargement of airspaces distal to terminal bronchiole (acinus)
Thinning an destruction of alveolar walls, large airspaces forme dby confluence of adjacent alveoli In pure emphysema, fibrosis is absent |
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Which types of emphysema are most important clinically? Which is more common?
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Centriacinar--20X more common than panacinar
Panacinar |
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Who is affected by centriacinar emphysema?
Where is it distributed? |
AKA centrilobular or proximal acinar
Occurs in heavy smokers who are also likely to have chronic bronchitis; rarely seen in nonsmokers Distal alveoli spared. Lesions present in apices. Also present in coal worker's pneumoniosis |
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Who is affected by panlobular emphysema?
Where is it distributed? |
AKA Panlobular emphysema
Most prominent in bases; uniform enlargement throughout the acinus Hardest to diagnose Occurs in alpha-AT deficiency |
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Who is affected by distal acinar emphysema?
Where is it distributed? |
Results in pneumothorax in otherwise healthy people
Affects distal acinus with proximal acini spared; often adjacent to to areas of scarring. |
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What is the most comon form of emphysema?
Where is it distributed? |
Irregular emphysema (most common, least clinically significant)
Results in irregular enlargement throughout acinus; seen frequently in areas of scarring |
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List and describe the three types of localized air expansion.
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Bleb: collection of air within pleura
Cyst: closed cavity lined by bronchial/bronchiolar epithelium or fibrous tissue Bulla: emphysematous space w/lung parenchema >1cm in diameter. |
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alpha1-antitrypsin:
Function When does deficiency result? Consequences of deficiency? |
Antiprotease
There are many variants that still undergo normal folding, but the PiZZ variant results in severe deficiency, manifesting as slow, abnl protein folding in the ER of the hepatocyte al-AT aggregates do not migrate to Golgi apparatus and lack of secretion into circulation Results in liver dz and/or emphysema |
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How does a1-AT deficiency result in emphysema?
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imbalance of elastase (wants to destroy elastic tissue) and antiprotease (wants to destroy elastase) results in net destruction of alveolar wall
Principal anti-elastase factor is alpha1-AT |
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Elastase is produced by _____.
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Nphils and macs
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How does smoking result in emphysema?
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1)Increases elastase activity, decreases anti-elastase activity:
-Inc'd alveolar nphils and macs -Release of nphil chemotactic factors from macs -Stimulated Signs of hyperinflation--seen in COPD, asthma (air-trapping) -Release of elastase from nphils -Inc'd elastase activity of macs; mac elastase NOT inhibited by alpha1-AT -Oxidants in smoke inhibit alpha1-AT 2) Free radicals present in tobacco smoke overwhelm antioxidant protection in lungs (antioxidants: superoxide dismutase and glutathione) -Oxidation also inactivates antiproteases |
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Why does emphysema due to smoking affect the ______ lobes?
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Emphysema affects lower lobes bc there is greater perfusion and quantity of nphils in the lower lungs. Results in panacinar emphysema.
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Why does emphysema due to a1-AT deficiency affect the ______ lobes?
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a1-AT deficiency localized to upper lobes; bc relatively smaller amount of a1-AT delivered to that region.
Resutls in centriacinar emphysema. |
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Who does chronic bronchitis tend to affect?
General symptoms? Pathophysiology? |
City dwellers and smokers
Productive cough, degree hypoxemia (blue bloaters) Excess mucus in large airways; hypertrophy of submucosal glands and alterations in small bronchi/oles produce obstruction. If much obstruction present-->emphysema |
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Pathologic features of chronic bronchitis.
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Mucosa is hyperemic (enhanced blood supply_ an dswollen w/copious mucous or mucopurulent secretions
Mucous glands large with many goblet cells Sometimes squamous metaplasia (smoking) Narrowed bronchiole lumens due to goblet cell hyperplasia, inflammn, mucus plugging, fibrosis |
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What is the Reid Index of gland size?
Utility? |
Ratio of thickness of gland layer to thickness of bronchial wall to depth of cartilage
Normal ratio <0.4 If over 0.4-->chronic bronchitis |
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Briefly describe a Type I hypersensitivity reaction.
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Rapidly developing immunologic reaction occurring iwthin minutes after combination of antigen w/Ab bound to mast cells in individual that has been PREVIOUSLY SENSITIZED.
Susceptible individuals make strong TH2 (helper cells--recruitment) response to allergens. |
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What is bronchial asthma?
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Chronic inflammatory disorder of airways that cause recurrent episodes of wheezing, dyspnea, chest tightness, and cough, particularly at night or in the early morning.
Results in chronic airway inflammn and hyperresponsive bronchi; mostly assocd with atopy (type I hypersens rxn) |
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Extrinsic vs Intrinsic Bronchial Asthma:
General Provide Examples |
Extrinsic:
Atopic (allergic) asthma Occupational asthma Bronchopulmonary aspergillosis Intrinsic: ASA ingestion, viral infections, exposure to cold, inhaled irritants, stress, or exercise |
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Inhaled allergens elicit a Th__-dominated response favoring production of _____ and recruitment of ________.
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Inhaled allergens elicit TH2 dominated response favoring IgE production and eosinophil recruitment.
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Describe the TH2 and ADAM-33 theories of atopic asthma.
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-TH1 and TH2 dcells usually inhibited by cytokines released by each other. In atopic asthma, may have imbalance in which TH2 cells not inhibited by IFN-gamma released by TH1 cells, thus resulting in promotion of inflammn.
-ADAM-33 is a matrix metalloproteinase expressed by fibroblasts and bronchial SM; may play role in remodeling of airways that occur prior to onset of asthma. |
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What occurs during the immediate phase of asthma? Manifesting symptoms?
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Immediate phase = re-exposure to allergen
Mast cells on mucosal surface simulated by IgE, release chemical mediators and directly stimulate subepithelial psymp receptors resulting in bronchoconstriction, edema from inc'd cap perm, mucus secretion, and hypotn in severe cases. |
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What occurs during the late phase of asthma?
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Mast cells releasing cytokines have recruited ephils, nphils, monocytes, lymphocyts, and bphils.
Bronchial epithelial cells release EOTAXIN which attracts and activates ephils. Ephils dump MAJOR BASIC PROTEIN which causes epithelial damage and bronchoconstriction. Occurs a few hours after re-exposure, persists for a day. |
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Gross and histologic pathologic features of asthma.
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Gross: overinflated lungs; bronchi and bronchioles occluded by mucus plugs
Histologic: edema and inflammn of bronchial walls, thick BMs, inc'd size of submucosal glands, SM hypertrophy |
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What are Curshmann's spirals?
What do they indicate? |
Curschmann's spirals refers to a finding in the sputum of spiral shaped mucus plugs (inspissates mucous). Indicative of asthma.
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What is Charcot-Leyden protein?
What does it indicate? |
Charcot-Leyden protein is a major autocystallizing constitutent of human ephils and bphils; indicative of asthma.
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What is bronchiectasis?
Associations? |
Chronic, necrotizing infection of bronchi with permanent dilation
Assocd w/: Bronchial obstruction, tumors, foreign bodies Necrotizing pneumonia, TB, staph Hereditary conditions: Cystic fibrosis Congenital bronchiectasis Intralobar sequestration Immunodeficiency states IMMOTILE CILIA |
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Gross and histologic appearance of bronchiectasis.
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Gross; Saccular, fusiform, or cylindroid dilations in airways.
Microscopic: Dilated airways with thin, inflamed wall with areas of necrosis and squamous metaplasia. Fibrosis if chronic. |
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What does bronchiectasis appear like in cystic fibrosis?
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Squamous metaplasia, impaired ciliary motion, necrosis of walls
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What is Kartegener Syndrome?
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Absence of dynein in arms; immotile cilia
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Lung changes of aging.
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Changes of mild emphysema
Alveoli and capillaries decrease in quantity-->decreased diffusion capacity -->Dec'd muscle mass of diaphragm Results in dec'd mucociliary action, blunted cough reflex, disorders of swallowing and esophageal motility Dec'd cellular and humoral immunity |
