Question

Match the following examples with their respective types of barriers:

Column I	Column II
A. Saliva	i. Physiological
B. Leukocytes	ii. Physical
C. Mucus	iii. Cytokine
D. Interferons	iv. Cellular

• A. A $\to$ i, B $\to$ iii, C $\to$ ii, D $\to$ iv
• B. A $\to$ ii, B $\to$ iii, C $\to$ i, D $\to$ iv
• C. A $\to$ i, B $\to$ iv, C $\to$ iii, D $\to$ ii
• D. A $\to$ i, B $\to$ iv, C $\to$ ii, D $\to$ iii

Answer 1

The correct option is D A $\to$ i, B $\to$ iv, C $\to$ ii, D $\to$ iii

Innate immunity consist of four types of barriers. These are:

Physical barriers : Skin on our body, mucus coating of the
epithelium lining the respiratory, gastrointestinal and urogenital
tracts which help in trapping microbes entering our body are physical barriers.

Physiological barriers : Acid in the stomach, saliva in the mouth, tears from eyes which prevent microbial growth are physiological barriers

Cellular barriers : Certain types of leukocytes (WBC) of our body like polymorpho-nuclear leukocytes (PMNL-neutrophils) andmonocytes and natural killer (type of lymphocytes) in the blood as well as macrophages in tissues that can destroy microbes belong to cellular barriers.

Cytokine barriers : Interferons secreted by virus-infected cells which protect non-infected cells from further viral infection form cytokine barriers.