MCAT Question A Day - 8/19/14 - Answer!
In an asthma attack, a patient suffers from difficulty breathing due to constricted air passages. The major causative agent is a mixture of leukotrienes called slow reacting substance of anaphylaxis. During an asthma attack, slow reacting substance of anaphylaxis most likely causes:
A. smooth muscle spasms of the bronchioles.
B. cartilaginous constriction of the trachea.
C. edema in the alveoli.
D. skeletal muscle spasms in the thorax.
A is correct. Constricted air passages is the clue. The bronchioles are surrounded by smooth muscle and small enough to constrict. Cartilage does not constrict, muscle does. The skeletal muscle in the thorax does not constrict the air passages. The alveoli are not part of the air passages.
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A is correct. Constricted air passages is the clue. The bronchioles are surrounded by smooth muscle and small enough to constrict. Cartilage does not constrict, muscle does. The skeletal muscle in the thorax does not constrict the air passages. The alveoli are not part of the air passages.
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