MCQ IN MEDICINE

Detailed explanation-1: -Answer and Explanation: T-cells are also a type of white blood cell that are present inside the body. T-cells are not considered as a physical barrier as these types of cells are produced or originated from the bone marrow and in the thymus, these cells will mature.

Detailed explanation-2: -Physical barriers including hair and stratum corneum, and chemical barrier such as antimicrobial peptides and lipids, restrict the overgrowth of bacteria on skin surface and prevent their invasion into the viable layers (Chen et al., 2018; Gallo and Hooper, 2012).

Detailed explanation-3: -The skin, mucous membranes, and endothelia throughout the body serve as physical barriers that prevent microbes from reaching potential sites of infection. Tight cell junctions in these tissues prevent microbes from passing through.

Detailed explanation-4: -Natural barriers include the skin, mucous membranes, tears, earwax, mucus, and stomach acid. Also, the normal flow of urine washes out microorganisms that enter the urinary tract. to identify and eliminate organisms that get through the body’s natural barriers. (See also Overview of Infectious Disease.