Leukocytes - granulocytes Flashcards
(40 cards)
Leukocyte are categorized as either
granulocytes or agranulocytes
granulocytes
contain primary and secondary cytoplasmic granules
how can leukocytes leave the blood stream
margination
pavementing (rolling and adhesion)
diapedesis
functions of leukocytes
initiate immune response
defend body against pathogens
chemotaxis (signal WBC to help w/ infection and inflammation)
“true cells” have nucleus and organelles
what signals WBC to respond by chemotaxis
cytokines
Leukopenia
reduced number of circulating WBCs
can be due to bacterial / viral infection exposure to toxins
causes immune response
leukemia
Leukocytosis
elevated WBC count
dehydration, allergy, infection
actively responding to infection producing lots of WBC
hematopoietic stem cells
can self-renew
produce 2 committed precursor cells: myeloid stem cell & lymphoid stem cells
why is self renewal of hematopoietic stem cells important
preserves the pool of stems cells and is critical for feeding the differentiation/maturation pathways
Primary granules
stain blue-purple
azurophilic granules
primary granules contain
lysosomal enzymes
secondary granules contain
lysozyme
alkaline phosphatases
variable staining
types of granulocytes
neutrophils
basophils
eosinophils
Neutrophil
most abundant (60-70% of leukocytes)
6-7 hours -> up to 4 days in CT
multi-lobed nucleus
Neutrophils act to
elimate opsonized bacteria
limit the extent of an inflammatory reaction in CT
enzymes in primary granules
elastase
myeloperozidase
enzymes in secondary granules
lysozymes
other proteases
specific receptors for integrins (ICAM-1 and ICAM-2) enable what
antibacterial and homing function of neutrophil
what WBC is the first to arrive in areas of tissue damage?
neutrophils
neutrophils play an important role in
phagocytosis of bacteria and dead cells
neutrophils are associated with what kind of inflammation
acute inflammation
Neutrophils are the only leukocyte that sometimes have tertiary granules what enzyme do tertiary granules contain
gelatinase (breaks down collagen)
Stab cells (band cells)
immature neutrophils
respiratory burst
bacterial killing by generating hydrogen peroxide and hypochlorous acid
excessive respiratory burst puts cells in oxidative stress
function of neutrophils