Asthma could be caused by all of the following except:
a. injection of acetylcholine antagonist
b. allergy
c. stimulation of parasympathetic
d. injection of histamine
e. inhibition of sympathetic
The correct answer and explanation is:
The correct answer is a. injection of acetylcholine antagonist.
Explanation:
Asthma is a chronic inflammatory disease of the airways that leads to wheezing, coughing, shortness of breath, and chest tightness. It is characterized by hyperreactivity of the airways, which results in bronchoconstriction and inflammation. Several factors can trigger asthma symptoms, but the injection of an acetylcholine antagonist is not one of them.
Here’s why each option affects asthma:
- b. Allergy: Allergic reactions are one of the most common triggers of asthma. When an individual with asthma is exposed to allergens like pollen, dust mites, or pet dander, the immune system overreacts. This leads to the release of inflammatory mediators like histamine, which causes the airways to narrow, resulting in asthma symptoms.
- c. Stimulation of parasympathetic: The parasympathetic nervous system, when stimulated, promotes bronchoconstriction. In asthma, overactivity of the parasympathetic nervous system can worsen symptoms, as it causes smooth muscles in the airways to contract, narrowing the air passages.
- d. Injection of histamine: Histamine, a mediator released during allergic reactions, can trigger asthma. When histamine is injected or released in the body, it causes bronchoconstriction and inflammation, leading to asthma symptoms. This is why histamine antagonists (antihistamines) are often used to treat allergic asthma.
- e. Inhibition of sympathetic: The sympathetic nervous system, when activated, causes bronchodilation, allowing for easier airflow. However, inhibition of the sympathetic system leads to bronchoconstriction, which can exacerbate asthma symptoms.
In contrast, an acetylcholine antagonist works to block the effects of acetylcholine, a neurotransmitter that can promote bronchoconstriction. Using an acetylcholine antagonist could reduce bronchoconstriction and alleviate asthma symptoms, so it is unlikely to cause asthma.