What are the kinds of defense mechanisms?

Answer 1

An animal must defend itself from foreign intruders, such as bacteria, viruses and other pathogens. It must also deal with abnormal cells that periodically appear in the body.Two cooperative defense systems that counter these threats have evolved.

* Non specific resistance * the immune system ans specific defense In the non specific system the body does not distinguish one infectious agent from another. This includes two lines of defense.

# external: consists of epithelial tissue eg skin, mucous membranes, # Internal: It is triggered by chemical signals and employs antimicrobial proteins and phagocytic cells that indiscriminately attack any invader that penetrates the bodys outer barriers.

The immune system responds specifically to the particular type of invader. This includes production of specific defense proteins called antibodies.It also involves the participation of several different types of cells that are decendents of white blood cells called lymphocytes. The immune sytem constitutes a third line of defense, which comes into play simmultaneously with the second.

Answer 2

The various skin glands , lacrymal glands , hairs at the entrance of nose , cough and sneeze reflexes , the mucus secreted by the epithelial linings of the respiratory and upper GIT , the many relatively innocuous microbes normally found on the skin and other linings exposed to the external environment and the acidic secretions of the stomach and uterus.

Answer 3

Denial, repression, displacement.

Answer 4

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