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Introduction to the Immune System (I) - Coggle Diagram
Introduction to the Immune System (I)
innate immunity
characteristics
not specific to any pathogen
rapid
first line of defence
components
anatomical barrier defense
skin
prevents penetration of pathogen
oil secreted by skin is slightly acidic to prevent growth of pathogenic bacteria
hair
mucous lining along tract
examples of tracts
reproductive
digestive
respiratory
urinary
innate immunity cells
granulocytic cells (releases granules to damage pathogens) :
phagocyte
neutrophil (50-70%)
3-lobed
kills ingested pathogens
eosinophil (1-3%)
2-lobed
releases granules that damages parasites
non phagocyte
basophil (< 1%)
1-lobed
releases granules in allergic response
weapons
phagocytosis
neutrophil extracellular trap (NET)
antimicrobial peptides (defensins)
pathogen recognition (PRR + PAM = immune cell activation)
pathogen associated molecular patterns (PAMPs)
characteristic cell surface proteins or types of genetic material
pattern recognition receptors (PRR)
expressed by phagocytic cells
adaptive immunity
characteristics
v specific
self / non self recognition
needs to be able to differentiate between pathogens and own cells, if not can lead to autoimmune disease
pathogen specifc
slow
diversity
can detect large number and types of pathogens
achieved through gene arrangement
memory
can rmb past encountered antigens
components
lymphocytes
B cells
matures at bone marrow
makes antibodies to bind to specific antigen
long-ranged effects
T cells
matures at thymus
expresses membrane-bound T cell receptors (TCR) to bind to specific antigen
pathogens
viruses
examples
covid
HIV
flu
bacteria
examples
TB
E coli
fungi
examples
yeast
athletes foot
unicellular eukaryotes
examples
malaria
immune system
leukocytes
myeloid progenitor lineage
red blood cells (non immune)
innate immunity cells
lymphoid progenitor lineage
lymphocytes (involved in adaptive immunity)
phagocytes
monocyte (monoclear phagocyte)
circulates in blood
matures into macrophage
macrophage (monoclear phagocyte)
present in tissue
phagocytoses foreign antigens
organs
primary / central lymphoid organs
site where lymphocytes are generated & developed
thymus
function
T cells from bone marrow migrate here for maturation
selection of T cells specific to non-self antigens happen here
shrinks with age due to immunosenescence
progressive loss of function of immune system with ageing
bone marrow
major sites
marrow of femur
humerus
hip bones
sternum
function
hematopoietic stem cells found here
myeloid cells produced here
lymphoid cells initially divide here
secondary / periphery lymphoid organs
sites where newly formed lymphocytes migrate to secondary lymphoid organs where they can react with foreign antigens
lymphatic system
components
appendix
adenoid
lymph nodes
functions
traps antigens
provides sites for lymphocytes to interact with antigen
process
a) cortex receives incoming lymph
b) follicles embedded in cortex receive and hold B cells
c) 1st contact: paracortex holds T cells
d) 2nd contact: mature B cells exits out of efferent cells
spleen
tonsils
functions
provide transport of immune cells
mainly lymphocytes
no erythrocytes (RBCs)
drains interstitial fluid from tissue
picks up antigens and white blood cellss