phagocytosis and immune response

what is a phagocyte

a type of white blood cell that performs phagocytosis by engulfing pathogens, carried in the blood and first cells to respond to an immune system trigger

B-cells

also called b-lymphocytes and are a type of white blood cell covered with antibodies which are proteins that bind to antigens to form an antigen-antibody complex. Each B-cell has a different shapes antibody on its membrane so different ones bind to different shaped antigens when an antibody onj surface of b-cell meets a complementary shaped antigen it binds to it this with substances from helper t-cells activate the B-cell. this is called clonal selection . the activated B cell divides into plasma cells

what are antibodies made from

amino acid chains

chemoattractions

chemicles that the phagocytes are attractes to

lung defence

cilia cells bring up mucus, epithelia covered in mucus

all antibodies have the same

constant regions

how do T-lymphocytes respond in different ways

helper cells- release chemical signals that activate and stimulate phagocytes and cytoxic t-cells which kill abnormal and foreing cells. helper t cells also activate B -cells which secrete antibodies

stomach defence

high acidity- low ph so enzymes denature

inflammation occurs because

histamine is produced at the site of infection which causes dilation of blood vessels and dilation speeds up the delivery of phagocytes to the site of infection

antigens

molecules usually proteins that can generate an immune response when detected by the body usually found on the surface of cells. antigens not normally in the body are described as foreign antigens

what are the two types of phagocytes?

neutrophils-smaller and quickly appear at the site of a wound monocytes-larger and appear about three days after infection and scavenge for bacteria, foreign particles and dead cellular material

pathogen

organism that causes disease

what happens after agglutination

phagocytes then bind to antibodies and phagocytose many pathogens at once which leads to the destruction of pathogens carrying the antigen

antibody production

plasma cells are identical to b-cells and secrete lots of antibodies specific to the antigen called monoclonal antibodies. they bind to the antigens on the surface of the pathogen to form lots of antigen-antibody complexes.

stages of phagocytosis

-phagocyte recognizes foreign antigen -cytoplasm of phagocyte engulfs pathogen -pathogen is now contained in a phagocytic vacuole -a lysosome fuses with phagocytic vacuole and the lysozmes break down the pathogen -pathogen then presents the pathogens antigens by sticking them to surface to activate immune response by acting as a antigen presenting cell

how many binding sites do antibodies have

2

what does the specificity of the antibody depend on

the variable regions which make up the binding site which is unique to its tertiary structure

blood types

there is type A which have A antigens, B have B antigens and AB which have both types of antigen, type O has no antigens therefore will reject A or B antigens

agglutination

when pathogens become clumped together by antibodies due to them having 2 binding sites

antigens in organ transplants ect

when you receive cells from someone those cells have antigens that are foreign to your body which trigger an immune response and if drugs aren't taken to suppress the recipients immune system the donor cells will be rejected

T-cells

T-lymphocyte, is a type of white blood cell with receptor proteins on its surface which bind to complimentary antigens presented by phagocytes