Question

when the memory b cell encounters the pathogen again, what happens? when the memory t cell encounters an antigen on an infected macrophage, what happens? immune system disorders sometimes the immune system overreacts to antigens or doesnt react at all. problems with immune system function can result in: allergies - overreacting to non - harmful agents and easily resolved with antihistamines in most cases (typically seen in 1st world countries). asthma - chronic disease in which narrowing of airways can happen due to a variety of reasons (smoke, exercise, stress, etc.) typically resolved with inhaled medications to relax airways and prevent damage. autoimmune disease - disease in which the body doesnt recognize its own cells. rheumatoid arthritis, lupus, type 1 diabetes, psoriasis are examples of these. hiv and aids - a viral disease that attacks the immune cells and their production. this can be fought with antiretrovirals, but most likely will lead to an eventual death by infection by a typically benign disease

Explanation:

When memory B - cells encounter the pathogen again, they rapidly differentiate into plasma cells that secrete antibodies specific to that pathogen. When memory T - cells encounter an antigen on an infected macrophage, they become activated and can directly kill infected cells or help other immune cells in their functions. Allergies are over - reactions to non - harmful antigens and are often managed with antihistamines. Asthma is a chronic disease with airway narrowing, treated with inhaled medications. Autoimmune diseases occur when the body attacks its own cells, with examples like rheumatoid arthritis, lupus, etc. HIV/AIDS is a viral disease that attacks immune cells and is treated with antiretrovirals but can lead to death from secondary infections.

Answer:

When memory B cell encounters the pathogen again: It differentiates into plasma cells to secrete antibodies.
When memory T cell encounters an antigen on an infected macrophage: It becomes activated to kill infected cells or assist other immune cells.
Allergies: Overreaction to non - harmful antigens, treated with antihistamines.
Asthma: Chronic disease with airway narrowing, treated with inhaled medications.
Autoimmune Disease: Body attacks its own cells, examples include rheumatoid arthritis, lupus, etc.
HIV and AIDS: Viral disease attacking immune cells, treated with antiretrovirals, can lead to death from secondary infections.