Question

A student on a school picnic to a park on a windy day started sneezing and having difficulty in breathing on reaching the park. The teacher enquired whether the student was allergic to something.

1. What is an allergy?
2. Write the two unique characteristics of the system involved in the response observed in the student.

Answer 1

a. Allergy is a hypersensitive immune response of the body to certain substances present in the environment called allergens (such as pollen grains, mites in dust, animal dander, etc.). When exposed to these allergens, the body releases chemicals like histamine from most cells, causing symptoms such as sneezing, watery eyes, a runny nose, and difficulty breathing.

b. Two unique characteristics of the immune system involved in the allergic response observed in the student are:

1. Rapid and hypersensitive reaction: Allergic reactions are usually very rapid in onset (within minutes) and are hypersensitive responses of the immune system to normally harmless substances (allergens).
2. Memory and specificity: The immune system remembers the allergen from previous exposure via memory cells and produces a stronger, quicker response upon re-exposure.