Sec 31.3: Immune Responses Flashcards
What are the two types of immune responses?
Specific and nonspecific responses
What are nonspecific responses?
They are immune responses that happen in the same way to every pathogen
What are specific responses?
They are immune responses that occur on a cellular level and are slightly different for each pathogen
What are the types of nonspecific responses?
Inflammation and Fever
What are the types of specific responses?
Cellular immunity and Humoral Immunity
What is inflammation?
It is a nonspecific response characterized by swelling, redness, pain, itching, and increased warmth at affected site
When does inflammation occur?
When pathogen enters the body and body’s other tissues become damaged
When does inflammation begin?
When mast cells or basophiles release chemicals called histamines in response to pathogen invasion
What do histamines do?
They cause cells in blood vessels to spread out
What happens after histamines are released?
Fluids move out of the blood vessel and into surrounding tissues, and white blood cells squeeze out of capillaries and move to site of infection, where they fight it off until swelling stops and tissue repair begins
When does fever begin?
When mast cells or macrophages release chemicals that cause the hypothalamus to increase the body’s temperature
What is low fever and what does it do?
Low fever is around 37.7 c, and it stimulates the production of interferons and increases the activity of white blood cells by increasing the rate at which they mature
What does increasing the rate of white blood maturity do?
It accelerates the body’s fighting off of infection
What is high fever and what does it do?
High fever is more than 39 c, and it causes the hypothalamus to be unable to regulate body temperature, and enzymes that control chemical reactions in the body stop functioning
What are antigens?
They are protein markers on the surfaces of cells and viruses that help the immune system identify a foreign cell or virus
How do specific responses lead to acquired immunity?
The body produces memory cells after fighting off a pathogen, which in turn destroy the pathogen if it reinvades the body
What are memory cells?
They are specialized T and B cells that “remember” an antigen that has previously invaded the body and destroy it when it reinvades
What is cellular immunity?
It is an immune response depending on T cells
What are antigen-presenting cells?
They are phagocytes that display foreign antigens on their membrane
What happens in cellular immunity?
Phagocyte engulfs foreign invader and displays the pathogen’s antigens on the membrane surface -> T cell binds to antigen-presenting cell, which releases proteins that activate the T cell -> activated T cell divides into activated T cells and memory T cells, which are reserved for the future -> Activated T cells bind to and destroy infected body cells
What is humoral immunity?
It is an immune response depending on antibodies
What happens in humoral immunity?
Pathogen binds to a B cell, which engulfs the pathogen and keeps a part of the antigen attached to its antibody -> T cell binds to trapped antigen fragment and stimulates B cells -> B cells divide into memory B cells and activated B cells -> Activated B cells produce antibodies that cause the pathogens to clump -> Phagocytes destroy pathogen clumps
What is tissue rejection?
It occurs when the immune system of the recipient of a blood or organ donation makes antibodies against the protein markers on the donor’s tissue
What are antigen receptors?
They are found on the surface of white blood cells, and they determine whether the immune system will attack or ignore a transplanted tissue
How do antigen receptors determine the fate of the transplanted tissue?
If the transplanted tissue’s protein markers fit into white blood cells, they are considered foreign and attacked, but if they do not interact with white blood cells, they are not detected
