Question

Which of the following engulfs foreign materials?
A. Macrophages
B. Plasma cells
C. Mast cells
D. Lymphocytes

Answer 1

The cells of the immune system perform various functions to remove foreign particles of the body. The process of engulfing foreign substances is called phagocytosis. It is performed by a specialized monocyte present in the blood.

Complete answer:
Option (a) is correct. Macrophages are a type of White Blood Cell. They form an integral part of the immune system. The primary function of macrophages is phagocytosis – a process by which a cell engulfs or internalizes a particle. Macrophages are in essence differentiated monocytes that circulate in the blood. Whenever they sense a foreign material, cellular debris, microbes or foreign materials, macrophages ingest the substances and initiate inflammation reactions.
Option (b) is incorrect. Plasma cells are also known as Plasma B cells. They are differentiated B cells that are formed in the bone marrow. The primary function of a plasma cell is antibody secretion. The antibodies after their secretion travel through the plasma and the lymphatic system to the site of antigenic reaction. Once there, the antibodies initiate the process of destruction of the antigen or foreign particles.
Option (c) is incorrect. Mast cells are granulocytes circulating in the blood. Mast cells comprises granules containing heparin and histamine and form a part of the immune system. Mast cells act to initiate inflammatory responses in the body.
Option (d) is incorrect. Lymphocytes are a type of white blood cells found primarily in the lymphatic system. Lymphocytes form an integral part of the acquired immune system of the body. There are two types of lymphocytes – T cells and B cells. T cells function to destroy cells that are infected by foreign particles like microbes, bacteria, virus, etc. B cells secrete antibodies, specific to an antigen that attack and destroy the antigen.

Hence, the correct answer is option (B).

Note: The immune system is concerned with identification and elimination of antigens in the body. Phagocytosis is a process by which particular cells of the immune system ingest or engulf foreign particles. Macrophages are a type of phagocyte that internalize antigens present in the body. They are also capable of producing inflammatory responses.