Question

Read the following passage and answer the questions that follow :

Immunity in our body is of two types (i) Innate immunity, and (ii) Acquired immunity. Innate immunity is a non-specific defence mechanism, whereas Acquired immunity is pathogen specific. Acquired immunity is characterised by memory. Antibodies are specific to antigens and there are four types of antibodies produced in our body - IgA, IgE, IgG and IgM. It shows primary response where it encounters the pathogen for the first time and secondary response during the subsequent encounters with the same antigen/pathogen. These immune responses are carried out with the help of two special types of lymphocytes present in the blood.

(i) Name any two barriers present in our body that provide innate immunity.

Hint:

Think of the physical, physiological, cellular and cytokine barriers and name any two.

Answer 1

Step 1: Understand the question:
Innate immunity is present from birth. It works through four kinds of barriers: physical, physiological, cellular and cytokine barriers.

Step 2: List the barriers and pick two:
Physical barrier: the skin and the mucus coating of the respiratory, gastrointestinal and urogenital tracts, which stop microbes from entering.
Physiological barrier: acid in the stomach, saliva in the mouth and tears from the eyes, which stop microbial growth.
Cellular barrier: neutrophils, monocytes, natural killer cells and macrophages, which engulf or destroy microbes.
Cytokine barrier: virus-infected cells secrete interferons, which protect non-infected cells.

Final Answer:
Any two barriers: physical barrier (skin, mucus coating) and physiological barrier (stomach acid, saliva, tears).