Explain the mechanism of action of the body’s acquired (specific) defenses, cell

he Immune response is governed by 2 different parts of the immune system.

Humoral Immunity: results in the production of antibodies that circulate around the body in blood and lymph (humors). Defends against: free bacteria and viruses.

Cell-mediated Immunity: defense activities are carried out by specialized cells circulating around the body. Defends against: host cells infected with bacteria and viruses, fungi and protozoans, tissue transplants, own cancer cells.

Cells of the Immune System:

Lymphocytes: White blood cells that are divided into 2 types:

B lymphocytes or B cells = secrete antibodies act in humoral immunity.
T lymphocytes or T cells = function in cell-mediated immunity.

Both originate from the bone marrow. They become B or T depending on their point of maturation. The T develop in the thymus gland found in the chest. The B develop in the bone. After this maturation process is complete they attain immunocompetence. This is their ability to do their appointed jobs. These cells eventually migrate to the lymph nodes and spleen waiting for their appropriate antigens to destroy.