Host Defenses I Flashcards
immune response definition
physiological process coordinated by the immune system to eliminate foreign substances
antigens defintion
foreign substances
3 lines of defense
innate barriers, innate immunity, adaptive immunity
what do innate barriers do
block infection
what does innate immunity do
destroy pathogens (no memory)
what does adaptive immunity do
specific responses (memory)
types of innate barriers
mechanical
chemical
physical
AMPs
examples of innate barriers
normal microbiota
mucus
stomach acid
urinary flow
what are AMPs
antimicrobial peptides
are AMPs generic or specific
generic
lymphatic system includes
primary and secondary lymphoid tissues
primary lymphoid tissues include
thymus and bone marrow
secondary lymphoid tissues include
MALT
lymph nodes
spleen
what is MALT
mucosa-associated lymphoid tissue
what is edema
tissue swelling
what is human blood made of
erythrocytes, platelets, and leukocytes
subcategories of leukocytes
granulocytes and agranulocytes
types of granulocytes
neutrophils
eosinophils
basophils
mast cells
neutrophil appearance
multi-lobed nucleus
neutrophil function
highly phagocytic
fights bacteria and viruses
eosinophil appearance
bi-lobed nucleus
eosinophil function
moderately phagocytic
attack allergens and parasites
basophil appearance
bi-lobed nucleus
basophil function
attack allergens and parasites
mast cell appearance
circular nucleus with granules
mast cell function
moderately phagocytic
attack bacteria, allergens, and parasites
reside in tissue
types of agranulocytes
monocytes
dendritic cells
lymphocytes
monocyte appearance
large horseshoe-shaped nucleus
monocyte function
highly phagocytic
mature into macrophages
activate adaptive immune response
dendritic cell appearance
ruffled membrane with long cytoplasmic extensions
dendritic cell function
highly phagocytic
activate adaptive immune response
lymphocyte appearance
small cells with large rounded nucleus
lymphocyte subcategories
NK cells
B cells
T cells
NK cell function
innate immunity
B and T cell function (general)
adaptive immunity
what percent of leukocytes are neutrophils
40-70%
another name for neutrophils
first responders
what are in granules
AMPs
destructive enzymes
pro-inflammatory enzyme
“respiratory burst”
what is phagocytosis
digest bacteria
what are NETs
neutrophil extracellular traps
what do NETs do
trap bacteria cells for phagocytosis
where are mast cells usually stationed
near body openings
two types of degranulation
piecemeal and anaphylactic
piecemeal degranulation
normal
encounters pathogen and only dumps some of the contents
anaphylactic degranulation
not normal
encounters pathogen and dumps all of the contents
what are the largest agranulocytes
monocytes
what percentage of leukocytes are monocytes
10%
what can cause increased levels of monocytes
chronic infections
inflammation
disorders
certain cancers
what are macrophages
mature monocytes that migrated out of the circulatory system
two types of macrophages
fixed and wandering
fixed macrophages
assigned to specific organs
wandering macrophages
travel, “on patrol”
apoptosis
programmed cell death
cytokines
signaling proteins
most cells can produce
chemokines
singaling molecules
activate chemotaxis
inflammatory
chemotaxis
cell movement in response to cellular stimuli
interleukins (ILs)
activate innate and adaptive immune responses
hematopoiesis
production of new blood cells and platelets
IL-1 family
regulates inflammation
generates fever
stimulates innate and adaptive immune responses
IL-2 family
influences T-cell development
immune system self-tolerance
interferons (IFNs)
interfere with viral replication
activates immune responses
which IFNs are made by virus-infected cells
alpha and beta
which IFN is made by NK and T cells to activate macrophages
gamma
tumor necrosis factor (TNFs)
regulate immune cells and inflammation
capable of killing tumor cells
which TNF is mainly produced by macrophages to induce inflammation
alpha
three ways interferons deal with infected cells
- slow protein synthesis
- apoptosis
- activate leukocytes
3 pathways of the complement system
classical, alternative, lectin
classical pathway
complement proteins activated when antibodies bind to a pathogen
alternative pathway
complement proteins activated by directly interacting with pathogen
lectin pathway
complement proteins activated when MBL binds to pathogen
what do all pathways lead to
C3
C3 splits into
C3a and C3b
what does C3a do
cause inflammation
what does C3b do
- opsonization
- cleave C5
opsonization
complement protein tags pathogen for phagocytosis
C5 cleaves into
C5a and C5b
what does C5a do
cause inflammation
what does C5b do
cytolysis
what is cytolysis
formation of MAC
what is MAC
membrane attack complex
causes leaky membrane
inflammation
innate immune response that develops after tissue damage
what does inflammation do
recruit immune defenses to injured site
limit spread of infection
allow for tissue recovery
cardinal signs of inflammation
redness
pain
localized heat
swelling
loss of function
what vascular changes does inflammation cause
vasodilation and increased vessel permeability
margination
leukocytes adhere to vessel wall
diapedesis
leukocytes squeeze out of vessel
angiogenesis
growth of new blood vessels
how is inflammation stopped
anti-inflammatory signaling molecules
how are leftover leukocytes dealt with after inflammation
apoptosis (pus)
what happens to exudate after inflammation
collected by lymphatic system
what is fever
abnormally high systemic body temp
what are pyrogens
fever-inducing agents
how does fever occur
cytokines signal hypothalamus to raise body temp
low-grade fever is
good for immunity but bad for body
low-grade fever range
99.5-101
what does low-grade fever do
enhance interferons
increase phagocytic efficiency
enhance leukocyte production
limits pathogen growth
promotes tissue repair
at what point is a fever life-threatening
105
at what point is a fever fatal
109.4
