the immune system Flashcards
innate immunity is?
nonspecific protection the body provides against various invaders
why is skin apart of innate immunity?
it is the first barrier against the entry of microorganisms
why are tears, saliva, and blood apart of innate immunity?
they contain lysozyme which kills some bacteria by destroying their cell walls
why is the stomach apart of innate immunity?
the extreme acidity destroys many pathogens ingested with food
why WBC are apart of innate immunity?
macrophages and neutrophils because they are first line of defense with WBC and phagocytize microorganisms such as bacteria, parasites, viruses
humoral immunity is?
specific protection by antigens (Ab) and immunoglobulins (Ig)
IgM:
location?
function?
blood and B cell surface
initial immune response
*IgM is pentameric (5 subunits) in blood and monomeric on B cells, as antigen receptor
IgG:
location?
function?
blood
involved in ongoing immune response
majority of antibody in the blood is IgG and can also cross placental barrier
IgD:
location?
function?
B cell surface
serves with IgM as antigen receptors
IgA:
location?
function?
secretions such as saliva, mucus, tears, breast milk
secreted in breast milk to help protect newborns
*has dimeric structure
IgE:
location?
function?
blood
involved in allergic reactions
an epitope is?
small site that an antibody recognizes within a larger molecule
an antigen (Ag) is?
molecule that an antibody binds to
*Ag are often large and have many different recognition sites for different Ab
Ab work to remove antigens by binding to it which results in three possible process?
1) the Ab bind inactivates Ag to prevent virus from binding to other cells
2) Ab binding can activate phagocytosis by macrophages and neutrophils
3) presence of Ab can active complement system to form holes in membrane and lyse the cell
why is the complement system is apart of innate immunity
it is a group of 20 blood proteins that nonspecifically bind to surface of foreign, leading to destruction
which lymphocyte activates plasma cells to produce antibodies?
B cells
when antigen binds to the antibody on the surface of an immature B cell, the cell proliferates and results as one of two cell types?
plasma cell or memory cell
if immature B cell becomes a plasma cell, what does it do?
it actively produces and secretes antibody into plasma