How does an antihistamine work?
By blocking the effects of histamine in the body
By reducing inflammation in the body
By increasing the production of histamine in the body
By stimulating the immune system
The Correct Answer is A
A) By blocking the effects of histamine in the body:
Antihistamines are pharmacological agents that work by antagonizing the effects of histamine, a chemical mediator released by mast cells and basophils in response to allergens or other triggers. Histamine contributes to various allergic symptoms such as itching, sneezing, nasal congestion, and watery eyes. Antihistamines exert their effects by competitively binding to histamine receptors (specifically H1 receptors) on target cells, thereby preventing histamine from binding and exerting its physiological effects. By blocking histamine receptors, antihistamines inhibit the action of histamine, leading to the alleviation of allergy symptoms.
B) By reducing inflammation in the body:
While some medications, such as corticosteroids, exert anti-inflammatory effects by suppressing the immune response and inhibiting the production of inflammatory mediators, antihistamines primarily target histamine receptors and do not directly reduce inflammation. Although histamine release can contribute to inflammation, antihistamines mitigate allergic symptoms primarily by blocking the action of histamine rather than by directly reducing inflammation.
C) By increasing the production of histamine in the body:
This statement is inaccurate. Antihistamines do not increase the production of histamine; instead, they counteract the effects of histamine by blocking its activity at receptor sites. The primary mechanism of action of antihistamines involves blocking histamine receptors to prevent histamine from exerting its physiological effects.
D) By stimulating the immune system:
Antihistamines do not stimulate the immune system. Instead, they act as antagonists to histamine receptors, thereby inhibiting histamine-induced responses. While histamine is involved in immune responses and allergic reactions, antihistamines do not directly modulate immune function or stimulate immune activity. Their primary role is to alleviate allergy symptoms by blocking the effects of histamine."
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
A) The sympathetic nervous system is responsible for "fight or flight":
This is the correct answer. The sympathetic nervous system is responsible for the "fight or flight" response, which prepares the body to react to perceived threats or stressors by increasing heart rate, dilating pupils, redistributing blood flow, and releasing stress hormones such as adrenaline and noradrenaline.
B) The sympathetic nervous system helps us to rest and digest:
This statement is incorrect. The parasympathetic nervous system is responsible for the "rest and digest" response, which promotes relaxation, digestion, and conservation of energy.
C) The sympathetic nervous system includes the cranial nerves:
This statement is incorrect. The sympathetic nervous system is primarily associated with the thoracolumbar region of the spinal cord and does not include the cranial nerves, which are primarily associated with the parasympathetic nervous system.
D) The sympathetic nervous system can lower blood pressure:
This statement is incorrect. The sympathetic nervous system typically increases blood pressure as part of the "fight or flight" response by increasing heart rate and constricting blood vessels to redirect blood flow to vital organs and muscles.
Correct Answer is A
Explanation
A) Loss of protective respiratory mechanisms due to prolonged irritation or damage:
Individuals with COPD often experience a progressive loss of protective respiratory mechanisms over time. Chronic exposure to irritants such as cigarette smoke leads to inflammation, structural changes in the airways, and destruction of lung tissue, impairing the body's ability to clear mucus, trap foreign particles, and maintain normal lung function. This loss of protective mechanisms contributes to the hallmark symptoms of COPD, including airflow limitation, chronic cough, and increased susceptibility to respiratory infections.
B) Localized swelling and inflammation within the lungs:
While inflammation is a hallmark feature of COPD, it typically manifests as widespread inflammation throughout the lungs rather than localized swelling. In COPD, chronic exposure to irritants leads to a systemic inflammatory response that affects the entire respiratory tract, including the bronchi and alveoli. This inflammation contributes to airway obstruction, mucus hypersecretion, and the development of respiratory symptoms.
C) An acute viral infection of the respiratory tract:
While individuals with COPD are at increased risk of respiratory infections, including viral infections such as influenza and respiratory syncytial virus (RSV), COPD itself is a chronic, progressive respiratory condition characterized by persistent airflow limitation. Acute viral infections may exacerbate COPD symptoms and lead to worsening respiratory function, but they are not inherent features of the disease itself.
D) Inflammation and swelling of the sinus membranes over a prolonged period:
Sinus inflammation and swelling, known as sinusitis, are not typically considered primary features of COPD. While individuals with COPD may experience comorbid conditions such as chronic rhinosinusitis, which can contribute to respiratory symptoms and exacerbations, sinus inflammation is not a defining characteristic of the disease.
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