Question

Briefly describe the body’s normal response to injury and infection in terms of the different lines of defense; i.e., first, second and third.

Refer to the textbook and the Internet as needed to help find this information and support your responses to these questions.

Answer 1

Answer) The immune system is comprises of three lines of defence and they are as follows:

1. First line of defence: it is the very first defence layer of the body that protects the body by preventing the entry of pathogens . These are surface barriers that stop the entry if pathogens from skin and mucous membrane. A chemical is released by skin and mucous membrane that stop the growth of pathogens.

2. Second line of defence: cellular and molecular response is the second line of defence. They stop the entry of every type of infections. Activity of immune system is regulated by anti microbial proteins. Second line of defence comes in action when first line of defence is unable to stop the entry pf pathogens in the body.

3. Third line of defence: lymphocytes is the third line of defense. It produces antibodies that act against the antigens. Theybact upon specific antigens. These B cells produces antibodies for number pf specific antigens and the presence of B cells is millions in the body.