A1 the immune system Flashcards
the immune system
pathogen size smallest to largest
viruses (nanometres)
bacteria (1-10um micrometers)
fungi (5-100 micrometers)
protozoa (5-100 micrometres)
worms (several mm-cm)
phagocytes
2-8% wbc
monocytes
macrophages
dendritic calls (DC)
eat things
granulocytes
eosinophils 1-4% wbc
neutrophils 40-60% wbc
basophils & mast cells 0.5-1% wbc
release toxic compounds
natural killer cells (NK cells)
2-3% wbc
type of lymphocyte
kill virally infected cells and tumour cells
lymphocytes
20-40% wbc
T cells
CD8+ cytolytic t cells 20%
-kill virally infected cells, tumor cells and allografts
CD4+ helper t cells 45%
-Th1,Th2, Th9, Th17, regulatory t cells (Treg)
-help other cells by releasing cytokines
-regulate immune responses
Gamma delta T cells 5%
-immunoregulatory and cytotoxic
B cells
23%
make antibodies
3 main pathways
classical
lectin
alternative
what do the pathways result in (complement)
phagocytosis
-by opsonising antigens
inflammation
-by attracting macrophages and neutrophils
membrane attack
-by rupturing cell wall of bacteria to lyse cells
cytokines
small (5-20 kDa) secreted proteins
chemokins, interferons, interleukins, lymphokines, tumor necrosis facts
act through cell surface receptors
imp in host immune responses to ifection, inflammation, trauma, sepsis, cancer, and reproduction
antibodies
aka immunoglobulin (ig)
Y shaped, produced by plasma B cells
recognise pathogen epitopes
main functions
-neutralisation
-agglutination
-complement
5 classes (isotopes)
-IgA, IgD, IgE, IgG, IgM
innate v adaptive
innate
-inherent recogniton
-productive response
adaptive
-random recognition
-production response
what does adaptive system recognise
antigen
-mol recognised by specific lymphocyte (or antibody)
-not recognised by innate (only t or b cell)
epitope
-exact site on antigen that is recognised and bound by antibody or t cell
immunodeficiency
(hyporeactivity)
-neutrophil disorders
-antibody deficiency
-complement deficiency
-t-cell dysfunction
immunopathology
(hyperreactivity)
-systemic autoimmunity
-organ-specific autoimmunity
-allergies and asthma
-pathogen induced pathology