PATHOLOGY

Detailed explanation-1: -White blood cells protect your body against infection. As your white blood cells travel through your bloodstream and tissues, they locate the site of an infection and act as an army general to notify other white blood cells of their location to help defend your body from an attack of an unknown organism.

Detailed explanation-2: -White blood cells are the key players in your immune system. They are made in your bone marrow and are part of the lymphatic system. White blood cells move through blood and tissue throughout your body, looking for foreign invaders (microbes) such as bacteria, viruses, parasites and fungi.

Detailed explanation-3: -Innate immunity can be viewed as comprising four types of defensive barriers: anatomic (skin and mucous membrane), physiologic (temperature, low pH and chemical mediators), endocytic and phagocytic, and inflammatory.

Detailed explanation-4: -Natural killer cells (NK cells) are lymphocytes (white blood cells that mature in lymphoid tissues). NK cells kill pathogen‐infected body cells or abdominal body cells (such as tumors).