MCQ IN MEDICINE

Detailed explanation-1: -Mucus not only provides a physical barrier, it also contains chemicals that help protect us from pathogens. Epithelial cells also secrete chemicals that prevent infection. This is true of epithelial cells on our skin and in our digestive, respiratory, and genital tracts.

Detailed explanation-2: -Leukocytes patrol the blood and tissues throughout the body in search of intruders. When they detect a foreign substance, they send out signals and launch an immune attack. These disease-fighting cells are made in the bone marrow and are stored in many different places in the body such as the tonsils and adenoids.

Detailed explanation-3: -Antibodies, also known as immunoglobulins, are proteins that attach themselves to pathogens. This signals immune cells to destroy the pathogen.