Question

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.

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

Hint:

Think of skin and mucus linings.

Answer 1

Step 1: Recall:
Innate immunity is the defence we are born with. It has four types of barriers: physical, physiological, cellular and cytokine barriers.

Step 2: Choose two barriers:
Physical barrier: the skin stops entry of microbes.
Physical barrier: the mucus coating of the epithelium lining the respiratory, gastrointestinal and urogenital tracts traps microbes.

Step 3: Other examples:
Physiological barriers include acid in the stomach, saliva in the mouth and tears from the eyes. Cellular barriers include leucocytes such as neutrophils and macrophages.

Final Answer:
Skin and the mucus-coated epithelial lining of the body tracts (any two barriers).