Match List-I with List-II:
| List-I | List-II |
|---|---|
| Types of barriers | Examples |
| (A) Cytokine barriers | (I) Mucus coating |
| (B) Physical barriers | (II) Tears from eyes |
| (C) Cellular barriers | (III) Phagocytosis |
| (D) Physiological barriers | (IV) Interferons |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A)-(IV), (B)-(I), (C)-(III), (D) - (II)
(A) Cytokine barriers — this matches (IV) Interferons. Cells infected by a virus secrete proteins called interferons. These signal proteins protect the cells that are not yet infected from further viral infection.
(B) Physical barriers — this matches (I) Mucus coating. The skin and the mucus coating of the lining of the respiratory, digestive and urogenital tracts physically stop microbes from entering the body. Mucus also traps the microbes.
(C) Cellular barriers — this matches (III) Phagocytosis. Certain white blood cells, such as neutrophils and monocytes, and the macrophages in tissues swallow and destroy microbes. The barrier is made of cells, so it is cellular.
(D) Physiological barriers — this matches (II) Tears from eyes. Acid in the stomach, saliva in the mouth and tears from the eyes are body secretions that prevent the growth of microbes.
NCERT Extract:
Innate Immunity – “Innate immunity is non-specific type of defence, that is present at the time of birth. This is accomplished by providing different types of barriers to the entry of the foreign agents into our body. Innate immunity consist of four types of barriers. These are —
(i) Physical barriers : Skin on our body is the main barrier which prevents entry of the micro-organisms. Mucus coating of the epithelium lining the respiratory, gastrointestinal and urogenital tracts also help in trapping microbes entering our body.
(ii) Physiological barriers : Acid in the stomach, saliva in the mouth, tears from eyes–all prevent microbial growth.
(iii) Cellular barriers : Certain types of leukocytes (WBC) of our body like polymorpho-nuclear leukocytes (PMNL-neutrophils) and monocytes and natural killer (type of lymphocytes) in the blood as well as macrophages in tissues can phagocytose and destroy microbes.
(iv) Cytokine barriers : Virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection.”