Immune system Flashcards
What does innate immunity include?
1) skin (barrier)
2) stomach acids and digestive enzymes
3) phagocytotic cells
4) chemicals in the blood
what does injury to tissue result in?
inflammation- wall off the affected tissue and local lymph vessels from the rest of the body impeding the spread of infection
what are the infectious agents first attacked by?
macrophages then neutrophils come onto the scene. most neutrophils are stored in bone marrow , but some are found circulating in the blood or in the tissues. neutrophils move toward infected or injured areas, drawn by chemicals (chemotaxis)
what are the two types of acquired immunity?
humoral or B cell immunity
cell mediated or T cell immunity
what is humoral immunity?
promoted by B lymphocytes - each is capable of making an antibody which it displays on its membrane
what happens when the B lymphocyte antibody contacts a matching antigen (presented by macrophage)?
the b lymphocyte assisted by helper T cell differentiate into plasma cells and memory b cells
what do the plasma cells do?
start making free antibodies. the free antibodies may attach their base to the mast cells. when an antibody whose base is att to the mast cell also binds an antigen, the mast cells releases histamine and other chemicals.
what do memory cells do?
memory B cells proliferate and remain in the body. in case of re-infection they can be called upon to make antibodies , resulting in a faster acting and more potent effect called the secondary response.
what is cell mediated immunity ?
involves t lymphocytes, which mature in the thymus.
t lymphocytes never make free antibodies. in thymus t lymphocytes are tested against self antigens, if it binds to one its destroyed. if it dosent, its released to lodge in lymphoid tissue or circulate between the blood and the lymph fluid.
what happens to t lymphocytes that pass the test in the thymus?
they differentiate into helper T cells, memory T cells, suppressor T cells and killer T cells (cytotoxic).
helper T cells: assist in activating the b lymphocytes as well as killer and suppressor T cells. (these are the ones attacked by HIV)
Supressor t cells: have a negative feedback role in the immune system
imagine a bacterial infection
first we get inflammation. macrophages then neutrophils engulf the bacteria.interstitial fluid is flushed into the lymphatic system where lymphocytes waiting in the lymph nodes. macrophages process and present antigen to b lymphocytes. with the help of the helper T cells, b lymphocytes will differentiate into memory cells and plasma cells. The plasma cells make antibodies which are released into the blood to attack bacteria.
a single antibody is specific for a ___ antigen
single
how many diff antibodies can a b lymphocyte make?
one!!
single b lymphocyte can only make one type of antibody
