Immune System Overview Flashcards
What are the different categories of leukocytes and list examples for each
granulocytes: neutrophils, eosinophils, basophils
agranulocytes: lymphocytes, monocytes
Where are leukocytes derived from and what are the cells involved called?
derived in bone cells from hematopoietic stem cells
what is process called where immune cells move from blood through tissues?
chemotaxis
what direction do immune cells travel in chemotaxis and why?
travel towards highest concentration of chemoattractants to fix injury/fight off pathogen
What is the process called when the resident macrophage sends a chemical signal to attract leukocytes?
leukocytosis
describe key characteristics of each of the granulocytes
neutrophil: most abundant, bacterial infection sites to kill
eosinophil: attack parasitic worms, asthma/allergy
basophil: histamine, vasodilation, attract other immune cells
describe key characteristics of agranulocytes
lymphocytes: assoc lymphoid tissue
monocytes: largest, leave bloodstream and become macrophages or dendritic cells
What receptors recognise own cells against foreign cells?
pattern recognition receptors (PRR)
what is the name of the specialised PRR that recognises different signs of pathogens and triggers the immune system to respond
toll like receptor (TLR)
what occurs once TLRs activated?
release of antiviral/proinflam cytokines/chemokines via inflam cascade
what immune cells conduct phagocytosis?
neutrophils and monocytes
describe the second process needed if phagocytosis does not effectively kill the pathogen
respiratory burst occurs where the neutrophil/monocyte consumes O2 to make destructive free radicals, killing the bacteria and itself simultaneously
what cell stimulates respiratory burst?
t helper cell
what is the main response to pyrogens and what cells can send them to the brain to initiate this outcome?
leukocytes and macrophages can send pyrogens to the brain to initiate fever
describe function of MHC proteins
let immune cells know if cells are foreign (to be targeted and killed) or self
how do MHC proteins hold identification peptides
deep groove
describe the diff MHC classes
class 1: appears on all self cells
class 2: on specific immune cells (foreign)
natural killer cells are a specialised type of what immune cell?
lymphocyte
describe functions of natural killer cells
kill cancer and viral infections by detecting non-specific cellular anomalies eg lack of self MHC
how do natural killer cells kill cells?
by inducing cytotoxic effects -> apoptosis, secrete potent inflammatory chemicals
differentiate between T cells and B cells
T cells born in bone marrow, go to thymus to mature and train then rejoin circulation and reside in secondary lymphoid tissue
B cells: made in bone marrow and mature there, join circ and go to secondary lymphoid tissue
what process in initiated once T/B cells activated?
clonal expansion
differentiate between humeral and cellular immunity
humeral: antibodies kill things (B cells)
cellular: cell kills things (T cells)
describe the training of T cells
1) immunocompetence- gain ability to recognise specific antigen by binding to it
2) self-tolerance- unresponsive to self-antigens
where are naive B/T cells exported to?
secondary lymphoid organs
what are most common places for first encounter bw immunocomp naive cell and antigen and what occurs?
lymph node or spleen, cell binds to receptor -> clonal expansion
what occurs once clonal expansion initiated?
proliferation and differentiation, most clones are effector T/B cells, some are memory
what type of cells are effector B cells and how many ABs can they secrete /second?
plasma cells, secrete 2000 AB molecules/s
what is achieved by memory B cells
immunological memory
list two key classes of T cells
CD4: T helper cells
CD8: cytotoxic T cells (respond to infection by binding)
