38 Questions
What is the primary function of histamine released during mast cell degranulation?
To induce smooth muscle constriction and bronchospasm
What is the source of mediators such as PAFs, prostaglandins, thromboxane, and leukotrienes?
Neutrophils
What is the function of the 5-lipoxygenase pathway of arachidonic acid metabolism?
Production of leukotrienes
What is the primary definition of asthma according to the National Asthma Education and Prevention Program?
A chronic inflammatory disorder of the airways
What is the effect of epithelial shedding on airway responsiveness?
Heightened airway responsiveness
What are the three most common signs and symptoms of bronchial asthma?
Cough, dyspnea, wheezing, and chest tightness
What is the result of the exudative inflammatory process and sloughing of epithelial cells into the airway lumen?
Impaired mucociliary transport
What is the primary cause of airflow limitation in asthma?
All of the above
What is the characteristic of expectorated mucus from patients with asthma?
High viscosity
What type of nerves are involved in maintaining the normal resting tone of airway smooth muscle?
Parasympathetic nerves
Which type of receptors in airway smooth muscle produce bronchodilation?
β2-adrenergic receptors
What is the primary characteristic of bronchial asthma?
Chronic airway inflammation
What is the effect of vagal stimulation on small bronchi?
Bronchoconstriction
What is the primary pathogenic mechanism of asthma?
Bronchial linings overreact to various triggers
What is the primary function of the non-adrenergic, non-cholinergic nervous system in the trachea and bronchi in asthma?
To amplify inflammation
What is the classification of asthma with symptoms occurring more than 2 times a week?
Mild Persistent
What is the range of severity of chronic asthma?
Mild intermittent symptoms to severe disabling disease
What is the primary response to allergen interaction with mast cell-fixed IgE?
Release of several spasmogens
What is the primary etiology of asthma?
Complex interaction of genetic and environmental factors
When are the symptoms of asthma most likely to occur?
At night or early in the morning
What is the result of the late phase response in asthma?
Progressing inflammatory reaction
What is the primary outcome of activation and degranulation of mast cells and basophils?
Recruitment of inflammatory cells
What is the primary consequence of inhaled allergens in asthma?
Activation of airway mast cells and macrophages
Which type of T-helper cells are involved in allergic inflammation in asthma?
Type 2 T-helper cells
What is the primary function of eosinophils in asthma?
Release of inflammatory mediators
What is the impact of asthma on lung function in adults?
Progressive loss of lung function
What is the primary characteristic of the late-phase inflammatory reaction in asthma?
Recruitment and activation of eosinophils
What is the result of an imbalance between TH1 and TH2 cells in asthma?
Allergic asthmatic inflammation
What is the primary consequence of plasma protein leakage in asthma?
Thickening of the airway wall
What is the risk associated with asthma?
Life-threatening acute exacerbations and asthma-related death
What is the hallmark of airway inflammation in asthma?
Eosinophilic infiltration of the airways
What is the primary presentation of chronic asthma?
Daily coughing, shortness of breath, and wheezing
What is the primary cause of airway narrowing in asthma?
Contraction of airway smooth muscle
What is the typical duration of the late-phase response in asthma?
24-48 hours
What is the primary diagnostic test for asthma in patients older than 5 years old?
Spirometry
What is the characteristic of airway hyperresponsiveness in asthma?
Exaggerated narrowing of the airways in response to a trigger
What is the primary characteristic of acute asthma?
Rapid onset of symptoms within 3-6 hours
What is the primary component of airway remodeling in asthma?
Airway smooth muscle hypertrophy
Study Notes
Respiratory Disorders
- Disease or trauma can interfere with the respiratory system's vital work, affecting the conducting airways, lungs, breathing mechanics, and neurochemical control of ventilation.
Asthma Definition and Pathogenesis
- Asthma is a chronic inflammatory disorder of the airways, characterized by recurrent episodes of wheezing, breathlessness, chest tightness, and coughing.
- In susceptible individuals, inflammation causes airflow obstruction that is often reversible either spontaneously or with treatment.
- The inflammation also causes an increase in bronchial hyperresponsiveness (BHR) to a variety of stimuli.
Pathogenesis of Bronchial Asthma
- Bronchial linings overreact to various triggers, causing smooth-muscle spasms that severely constrict the airways.
- Mucosal edema and thickened secretions further block the airways.
- Asthma is a complex disorder characterized by chronic airway inflammation, airflow limitation, and symptoms such as wheezing, breathlessness, chest tightness, and coughing.
Etiology of Asthma
- Asthma results from a complex interaction of genetic and environmental factors.
- The severity of chronic disease ranges from mild intermittent symptoms to a severe disabling disease.
Pathophysiology of Asthma
- The major characteristics of asthma include a variable degree of airflow obstruction, bronchospasm, edema, and hypersecretion, as well as airway inflammation.
- Inhaled allergens cause an early-phase allergic reaction, which activates airway mast cells and macrophages, releasing pro-inflammatory mediators that induce contraction of airway smooth muscle, mucus secretion, vasodilation, and exudation of plasma in the airways.
Late-Phase Inflammatory Reaction
- The late-phase inflammatory reaction occurs 6 to 9 hours after allergen provocation and involves recruitment and activation of eosinophils, T lymphocytes, basophils, neutrophils, and macrophages.
- Eosinophils migrate to the airways and release inflammatory mediators, cytotoxic mediators, and cytokines.
T-Lymphocyte Activation
- T-lymphocyte activation leads to the release of cytokines from type 2 T-helper (TH2) cells that mediate allergic inflammation.
- Conversely, type 1 T-helper (TH1) cells produce cytokines that are essential for cellular defense mechanisms.
Mast Cell Degranulation
- Mast cell degranulation in response to allergens results in the release of mediators such as histamine, eosinophil chemotactic factor, and leukotrienes.
- Histamine is capable of inducing smooth muscle constriction and bronchospasm and may play a role in mucosal edema and mucus secretion.
Airway Hyperresponsiveness
- Airway hyperresponsiveness is an exaggerated ability of the airways to narrow in response to a variety of stimuli.
Classification of Asthma
- Asthma can be classified as mild intermittent, mild persistent, moderate persistent, or severe persistent based on symptoms and lung function.
Clinical Presentation and Diagnosis
- Diagnosis is based on a detailed medical history, physical examination of the upper respiratory tract (URT) and skin, and spirometry for pulmonary function tests.
- Severity ranges from normal pulmonary function with symptoms only during acute exacerbations to significantly decreased pulmonary function with continuous symptoms.
This quiz covers the etiology and pathogenesis of bronchial asthma, a respiratory disorder that affects the conducting airways, lungs, and breathing mechanics. It also explores the neurochemical control of ventilation and its relation to asthma.
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