Which of the following is a selective H₁ ‚ receptor agonist?

Correct Answer: C

Rationale: In this quiz question, the correct answer is C) 2-Thiazolyl ethylamine. This is a selective H₁ receptor agonist because it specifically targets the histamine H₁ receptor in the body. Option A) 4-methyl histamine is not a selective H₁ receptor agonist; it is a histamine derivative but not specific to the H₁ receptor. Option B) Impromidine is a histamine H₂ receptor agonist, not H₁, making it incorrect in this context. Option D) Mepyramine is a first-generation H₁ receptor antagonist (antihistamine), so it works opposite to an agonist and is not selective in this case. Educationally, understanding the specificity of drugs targeting specific receptors is crucial in pharmacology. Selective agonists reduce side effects by targeting specific receptors, improving therapeutic outcomes. This knowledge is essential for healthcare professionals to make informed decisions regarding drug selection for respiratory conditions.

Correct Answer: C

Rationale: In the context of drugs affecting the respiratory system, understanding the mechanism of action of Bromhexine is crucial for healthcare professionals. The correct answer, option C, states that Bromhexine acts by depolymerizing mucopolysaccharides present. Bromhexine is a mucolytic agent that works by breaking down and thinning the mucus in the respiratory tract, making it easier to expectorate. Option A, inhibiting the cough center, is incorrect because Bromhexine does not directly act on the cough reflex in the brain. Option B, irritating gastric mucosa and reflexly increasing bronchial secretion, is incorrect as this describes the mechanism of action of expectorants like ammonium chloride, not Bromhexine. Option D, desensitizing stretch receptors in the lungs, is also incorrect as this is not a known mechanism of action for Bromhexine. In an educational context, knowing how Bromhexine works can help healthcare professionals make informed decisions when prescribing medications for respiratory conditions involving excessive mucus production. Understanding the specific actions of different drugs targeting the respiratory system is essential for providing effective patient care and managing respiratory disorders successfully.

Correct Answer: B

Rationale: In a patient with bronchial asthma, inhaled salbutamol produces bronchodilation. This is the correct answer (B) because salbutamol is a beta-2 adrenergic agonist that acts on beta-2 receptors in the smooth muscles of the bronchioles, leading to relaxation and widening of the airways, thereby improving airflow. Option A is incorrect because salbutamol does not inhibit antigen-antibody reactions in the lungs. It primarily acts on bronchial smooth muscles rather than the immune system. Option C is incorrect because salbutamol does not directly reduce bronchial hyperreactivity. While it can help alleviate symptoms of hyperreactivity by dilating the airways, it does not address the underlying hyperreactivity itself. Option D is incorrect because while salbutamol does cause bronchodilation (option B), it does not directly reduce bronchial hyperreactivity (option C), so the combination provided in option D is not accurate. From an educational perspective, understanding how medications like salbutamol work in the treatment of bronchial asthma is crucial for healthcare professionals to provide effective care to patients with respiratory conditions. It is important to differentiate between the mechanisms of action of different drugs to ensure appropriate and evidence-based treatment decisions.

Correct Answer: D

Rationale: In the treatment of chronic bronchial asthma, corticosteroids (option D) provide the most consistent, pronounced, and sustained relief of symptoms. Corticosteroids work by reducing inflammation in the airways, which is a key component of asthma pathophysiology. They help to decrease airway hyperresponsiveness and prevent exacerbations. Option A, β₁ sympathomimetics, primarily act on the heart and are not as effective in treating the underlying inflammation in asthma. Anticholinergics (option B) mainly work by dilating the airways but do not address the inflammation seen in chronic asthma. Sodium cromoglycate (option C) is a mast cell stabilizer that helps prevent the release of inflammatory mediators but is less effective in providing sustained symptom relief compared to corticosteroids. Educationally, understanding the mechanism of action of each drug class is crucial in selecting the most appropriate treatment for chronic bronchial asthma. It is essential for healthcare professionals to be aware of the most effective medications to manage asthma symptoms and prevent long-term complications. By choosing corticosteroids, healthcare providers can target the root cause of asthma symptoms, leading to improved patient outcomes and quality of life.

Correct Answer: D

Rationale: Chronic Bronchitis is a type of chronic obstructive pulmonary disease (COPD) characterized by inflammation and narrowing of the bronchial tubes. The correct answer, option D, stating "II and III are correct" is accurate because chronic bronchitis is associated with an increased number of mucous glands and goblet cells (II) leading to excessive mucous production, as well as edema and inflammation of the bronchioles (III) due to chronic irritation and inflammation. Option A, the destruction of central and peripheral portions of the acinus, is incorrect as this description aligns more with emphysema, another type of COPD where there is damage to the alveoli instead of the bronchial tubes. Option C, edema and inflammation of the bronchioles, is partially correct as inflammation is indeed a characteristic feature of chronic bronchitis, but edema specifically refers to fluid accumulation which is not a primary feature of chronic bronchitis. In an educational context, understanding the specific characteristics of chronic bronchitis is crucial for healthcare professionals to accurately diagnose and manage patients with this condition. Recognizing the increased mucous production and inflammation of the bronchioles can guide treatment decisions such as bronchodilator and anti-inflammatory medications, as well as smoking cessation interventions to improve patient outcomes and quality of life.