lecture 7 - immune system Flashcards
what is the immune system?
body’s defence against infectious organisms and other invaders.
- bacteria tries to make you ill, your immune system tries to fight it
what are the functions of the immune system?
protect, recognise, attack and destroy
what is innate (natural) immunity?
Response is non-specific
Exposure leads to immediate maximal response
No immunological memory
Found in nearly all forms of life
Activates the acquired arm of the immune system
what is acquired (adaptive) immunity?
Pathogen and antigen specific response
Lag time between exposure and maximal response
Exposure leads to immunological memory
Found only in jawed vertebrates
what is the main function of a neutrophil?
phagocytosis
what is the main function of a eosinophil?
to destroy parasites
what is the main function of a basophil?
inflammation
what happens during phagocytosis?
eats the cell - engulfs it - eats anything foreign in the body
what is the neutrophil function - the killing process (degranulation)?
respiratory burst - reactive o2 species - hydrochloric acid are released onto antigen
commits self suicide - when it performs its killing machinery it dies
what is the difference between a monocyte and a macrophage?
mono - in blood, macro - in tissue
why is it important a monocyte knows what it is fighting?
it talks to the acquired arm of the immune system
where are most lymphocytes found?
acquired arm of the immune system
is the innate immune system the first line of defence?
yes
what is an antigen presenting cells role?
display/present the invading antigen to the acquired arm of the immune system to activate it
what can lymphocytes be broken down to?
t cells and b cells
what is a t cell?
Mature in the thymus
60-70% lymphocytes
Cell-mediated (intracellular) response
Produce memory cells
what is a b cell?
Mature in the bone marrow
5-15% lymphocytes
Humoral (extracellular) response
Produce memory cells
what is a t helper subset?
orchestrates and co-ordinates the immune response
what is a t cytotoxic subset?
bind to and kills antigen specific infected cells
what is a t regulatory subset?
help to regulate/switch off the immune response to avoid chronic inflammation
is a type one helper intracellular or extracellular?
intracellular
is a type two helper intracellular or extracellular?
extracellular
why is it important to know whether it is a type one or type 2 helper cell?
it will put all its energy into the cell that will kill it - counterbalance and work against it
what is humoral immunity?
t helper cells still part of the initial process
t cell signals to the b cell that its a humoral and that it is extracellular - until a t helper cell to say go ahead and kill it
b cells produces an abundance of plasma cell - secretes antibodies which are specific to that particular antigen
cant directly kill an antigen - antibodies bind to the receptor sites and so cant bind to anything else - neutralises it
what are factors affecting the immune system?
drugs, alcohol, diet, exercise, early life events, smoking etc
what system does the immune system work with?
endocrine
