Final answer:
The immune system has two main responses to an antigen attack: the innate immune response and the adaptive immune response. The innate immune response is quick but non-specific, while the adaptive immune response is more specific and leads to immunity.
Step-by-step explanation:
The immune system has two main responses to an antigen attack: the innate immune response and the adaptive immune response. The innate immune response is quick but non-specific, providing general defenses against pathogens. It includes barrier defenses like the skin and mucous membranes, as well as phagocytic cells that engulf and destroy pathogens.
The adaptive immune response is more specific and takes longer to develop, but it leads to immunity. It involves lymphocytes, specifically B cells and T cells, which recognize and respond to antigens on pathogens. B cells produce antibodies that bind to antigens and target pathogens for destruction, while T cells directly kill infected cells.
When a person is re-exposed to the same pathogen, the adaptive immune response is faster due to memory cells that recognize the antigen. These memory cells allow for a quicker and more targeted immune response, preventing the emergence of the disease.