36 Questions
Which cells produce allergen specific IgE antibodies?
B cells
What happens when IgE receptors on mast cells are crosslinked by allergen specific IgE antibodies?
Mast cells undergo degranulation
Which of the following symptoms are associated with mast cell mediators?
All of the above
What is the role of allergen-specific IgE antibodies in IgE-mediated allergies?
They bind to the surface of mast cells and basophils
What is the typical sequence of events in IgE-mediated allergies?
Allergen exposure, IgE production, mast cell degranulation
Which of the following is the most appropriate treatment for allergic rhinitis and urticaria?
Systemic H1 antagonists
Which of the following is NOT a use of H1 antagonists?
Treating anaphylactic shock
What is the main cause of death in anaphylactic shock?
Respiratory obstruction and/or cardiovascular collapse
What is the first step in the treatment of anaphylaxis?
Stopping administration of antigen
Which of the following is the mechanism of action of glucocorticoids in the treatment of anaphylaxis?
Decreasing production of inflammatory mediators
Besides treating allergic rhinitis and urticaria, H1 antagonists are also used for which purposes?
Acting as anti-emetics and sedatives
What is the mechanism of action of adrenaline in the treatment of anaphylactic shock?
Producing vasoconstriction
Which medication is no longer recommended in routine treatment of anaphylaxis?
Glucocorticoids (e.g., hydrocortisone)
What is the effect of histamine release on the airways during anaphylactic shock?
Constriction of airways
Which complication can arise due to laryngeal edema during anaphylactic shock?
Suffocation
What is the main consequence of the widespread increase in vascular permeability during anaphylactic shock?
Loss of blood pressure
Which receptor does adrenaline primarily act on to cause vasoconstriction during anaphylaxis?
α1 adrenergic receptor
What happens when adrenaline binds to the β2 adrenergic receptor during anaphylaxis?
Bronchodilation
Which receptor is primarily targeted by adrenaline to increase heart rate and contractility during the treatment of anaphylaxis?
β1 adrenergic receptor
Which conformational state does the H1 receptor tend towards in the basal state?
Active state
What is the effect of histamine binding to the H1 receptor?
Shifts the equilibrium towards the active state
What is the mechanism of action of H1 antagonists?
Inverse agonists
What is the main difference between histamine and antihistamine in terms of receptor activation?
Histamine is a full agonist, while antihistamine is an inverse agonist
What is the primary effect of H1 antagonists on the equilibrium of the H1 receptor?
Shifts the equilibrium towards the inactive state
Which generation of H1 antagonists readily crosses the blood-brain barrier to block histaminergic actions in the CNS?
First generation
Which generation of H1 antagonists is less selective for the H1 receptor and may bind to cholinergic, alpha-adrenergic, and serotonergic receptors?
First generation
Which category of H1 antagonists is more selective for the H1 receptor and less likely to bind to other receptors?
Second generation
What is a characteristic of topical H1 antagonists in terms of onset of action and administration frequency?
They have a more rapid onset of action and require multiple administrations each day
Which generation of H1 antagonists is associated with CNS depression (drowsiness) and dry mouth as adverse effects?
First generation
Which second-generation H1 antagonist is ionized at physiological pH and does not cross the BBB?
Cetirizine
How long does it typically take for oral H1 antagonists to reach peak plasma concentrations after administration?
2-3 hours after administration
Where are most H1 antagonists metabolized?
Liver
What adverse effect is commonly associated with first-generation H1 antagonists?
Dry mouth
Which adverse effect is NOT commonly associated with antihistamines?
Increased sweating
What is the key mediator in atopy and anaphylaxis?
Histamine
Which receptor antagonist is used to treat dyspepsia?
H2 receptor antagonist
Test your knowledge on IgE mediated allergies and understand the process of sensitization and allergic reactions. Learn about the role of IgE antibodies, mast cells, and basophils in the body's response to allergens.
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