Which one of the following acts as a physiological barrier to the entry of microorganisms in human body?

Which one of the following acts as a physiological barrier to the entry of microorganisms in human body?
  1. Tears
  2. Monocytes
  3. Skin
  4. Epithelium of urogenital tract

Solution

Physiological barriers to the entry of microorganisms in human body are tears in eyes, saliva in mouth and $\mathrm{HCl}$ in stomach. The enzyme lysozyme is found in tears and saliva, and inhibits the synthesis of peptidoglycan present in the cell wall of microorganisms especially eubacteria.

Asked in: NEET 2011 (Screening)

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