MCQ IN MEDICINE

Detailed explanation-1: -A healthy immune system can defeat invading disease-causing germs (or pathogens), such as bacteria, viruses, parasites-as well as cancer cells-while protecting healthy tissue. Understanding how the immune system works and how we can help protect our bodies is essential to the fight against the COVID-19 pandemic.

Detailed explanation-2: -They do this by recognising substances called antigens on the surface of the microbe, or in the chemicals they produce, which mark the microbe or toxin as being foreign. The antibodies then mark these antigens for destruction. There are many cells, proteins and chemicals involved in this attack.

Detailed explanation-3: -After the first encounter with a pathogen, our immune systems generate a small number of cells that remain for a long time, are specific for that pathogen, and circulate in the blood, spleen and lymph nodes to keep watch for another encounter.