Select the Physiological barrier(s) for innate immunity?
A. Mucus coating of the epithelium lining of respiratory tract
B. Acid in the stomach
C. Tears in the eyes
D. Saliva in the mouth
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → B, C and D only
A. Mucus coating of the epithelium lining of respiratory tract — Incorrect. NCERT puts the mucus coating under physical barriers, along with the skin; it traps microbes.
B. Acid in the stomach — Correct. A physiological barrier.
C. Tears in the eyes — Correct. A physiological barrier.
D. Saliva in the mouth — Correct. A physiological barrier.
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.”