Lecture 11+12 Flashcards
first line of defense
physical barriers
chemical barriers
genetic barriers
a surface protection composed of anatomical and physiological barriers to keep microbes out
second line of defense
inflammatory response
interferons
phagocytosis
complement
a cellular and chemical defense system that comes into play when the infectious agents make it passed the first line defenses
third line of defense
B and T lymphocytes, antibodies, cytotoxicity
specific host defenses that must be developed for each microbe through the action of specialized WBC.
activity towards specific pathogens and formation of memory
innate arm of the immune system
immediate reaction
nonspecific
includes: barriers (skin, mucous membranes, acidity of stomach)
phagocytic cells
antimicrobial peptides
temp.
acquired (adaptive) arm of the immune system
develops in response to an infection
adapts to recognize and eliminate and remember pathogens
highly specific
takes several days for this arm to become fully functional
cell-mediated and antibody mediated immunity
self and non-self recognition
hematopoiesis
production of blood cells
all blood cells arise from Hematopoietic Stem Cells (HSC)
LM stem cells
- mother of all blood cells: lymphoid and myeloid elements
- may self-renew or commit to be a pluripotential
CFU-GEMM or CFU-L
can self renew or commit to progenitor cell
Progenitor
kinds of progenitor?
committed stem cells; limited self-renewal
1) Myeloid progenitors: granulocyte, macrophage,
monocyte, erythroid, megakaryocyte, eosinophil, basophil
2) Lymphoid progenitors: lymphocytes
Agranulocytes:
Lymphocytes and monocytes
granulocytes
basophil
neutrophil
eosinophil
Mononuclear Phagocyte System
Reticuloendothelial System
▪Network of connective tissue fibers and cells surrounding organs
Inhabited by phagocytic cells – mononuclear phagocyte system –ready to attack and
ingest microbes that passed the first line of defense
primary lymphoid tissues
bone marrow
thymus
secondary lymphoid tissue
spleen, adenoids, tonsils, lymph nodes, payer’s patches, MALT
thymus
T cell development and maturation
will induce death upon T cells that cant recognize self-MHC molecules or react to strongly to MHC molecules
function decreases with age
immature are more in the cortex and the mature are in the medulla
3 regions of the lymph node
cortex:
mainly B cells
paracortex:
T cells
activation of T cells and interaction of T and B cells
medulla:
plasma cells secreting Ab’s and macrophages
spleen
filters blood
activation of lymphocytes from blood borne pathogens
(important for systematic infections)
red pulp: remove of old or defective RBC and platelets
White pulp: PALS with T cells and follicles with B lymphocytes
marginal zone:
initiation of immune response
MALT (Mucosa-Associated Lymphoid Tissue)
Organized areas along digestive, respiratory, and
urogenital tracts
Pathogens are directly transferred across mucosa by Microfold cells (or M cells)
antigen factors in immunogenicity
foreignness
molecular size (Da)
chemical composition (greater complexity = higher immunogenicity)
adjuvant - enhance response
endemic
refers to the constant presence and/or usual prevalence of a disease or infectious agent in a population within a geographic area
Hyperendemic
refers to persistent, high levels of disease
occurrence.
Sporadic
refers to a disease that occurs infrequently and irregularly
Epidemic
refers to an increase, often sudden, in the number of cases of a disease above what is normally expected in that population in that area.
Pandemic
refers to an epidemic that has spread over several
countries or continents, usually affecting a large number of people
Leavell & Clark´s Levels of Disease Prevention
- primordial = population prevention (government policy)
- primary = prevent disease from occurring
- secondary = screening
- tertiary = treatment
- quaternary = prevent over treatment (preventing all types of harm
