Leukocytes Flashcards
granulocytes =
neutrophils, eosinophils, basophils
polymorphonuclear leukocytes (PMNs) usually refer to:
neutrophils
granulocyte granules are composed of:
lysosomes containing hydrolytic enzymes and antibacterial agents
at what developmental stage do primary granules appear?
late myeloblast/early promyelocyte stage
at what stage do secondary granules appear?
myelocyte stage
leukemia =
high leukocytes
myeloperoxidase stain stains for:
primary granules
when do neutrophil precursors stop undergoing mitosis?
at myelocytic stage (when indentation occurs)
pathway of maturation for eosinophil
myelocyte –> metamyelocyte –> band –> mature eosinophil
mononuclear leukocytes includes:
lymphocytes and monocytes
granular lymphocytes are either _____ or ______
NK cells or cytotoxic T lymphocytes
Which species tend to have high leukocytes?
pig,cat
Which species tend to have low leukocytes?
Human, sheep, cow
Most numerous leukocyte cell type in dogs, cats, horses
neutrophils
most numerous leukocyte cell type in pigs, ruminants, rodents
lymphocytes
T or F: monocytes, eosinophils, and basophils are typically present in blood from normal mammals
T
How do concentrations of neutrophils and lymphocytes change IMMEDIATELY after birth?
neutrophils increase, lymphocytes decrease. Later on, neutrophils decrease and lymphocytes increase
Why do neutrophils spike after birth?
they are released from the bone marrow post-partum
what happens to neutrophils that don’t come across an activated endothelial cell?
apoptosis within a few days of not being activated
Epinephrine/exercise –> circulating neutrophils
increases
Which survives longer in the blood: basophils or eosinophils?
eosinophils
What do monocytes develop into?
macrophages and dendritic cells
where are the marginating pools for monocytes and lymphocytes located?
lung capillaries
most lymphocytes located in:
lymphoid organs
most lymphocytes circulating in the blood are:
naive T and B lymphocytes
Rank from most to least common in the blood: T cells, B cells, NK cells
T cells > B cells > NK cells
memory lymphocytes
lymphocytes that have seen Ag. They are more likely than naive lymphocytes to migrate back to where they’ve seen an Ag in the past
What do lymphocytes bind to?
High endothelial venules (HEVs) in lymphoid organs or activated endothelial cells
Which has longest and shortest lifespans among T-lymphocytes, B-lymphocyes, and NK cells?
T-lymphocytes have longest lifespan, NK cells shortest lifespan
haptotaxis
directional motility or outgrowth of cells, usually in the direction of chemoattractants. Neutrophils utilize this to migrate through tissues and destroy invading bacteria
chemotaxis
a chemically prompted taxis, in which somatic cells, bacteria, and other single-cell or multicellular organisms direct their movements according to certain chemicals in their environment.
surface charge of neutrophils
negative
PAF =
platelet activating factor
3 things that activate endothelial cells to chemoattract neutrophils
thrombin (via coagulation)
histamine (via mast cells)
TNF/IL1 (via inflammation)
What happens when an endothelial cell is activated?
selectins and ICAM are upregulated on the surface of the cell, which upregulates adhesion and chemoattraction of neutrophils flowing by. Firm adhesion is achieved with integrin activation and binding, which is tighter than selectin binding.
Result of integrin deficiency
high white count in blood because neuts can’t migrate out through endothelial cells
do leukocytes adhere to the surface of arteries?
No, only veins
G-CSF and GM-CSF
growth factors for neutrophils in the tissues. Stimulate proper neutrophil function throughout life of the cell
chemoattractants for neutrophils
IL8, C5a, PAF, B4, bacterial products recognized by Toll-like receptors
myeloperoxidase
released into a phagosome to kill bacteria. Enhances H2O2 killing
nonenzymatic molecules in granules
lactoferrin (binds Fe), cationic proteins and peptides including defensins which are inserted in lipid bilayer
Neutrophil Extracellular Traps (NETS)
released by neutrophils. Contain proteins from granules that kill microbes without phagocytosis
eosinophils mainly found where? what is their fx?
GI mucosa. Defense against helminths. POOR defense against bacteria/viruses. Produce type 2 cytokine-induced inflammation
What do type 2 helper T lymphocytes recruit/activate?
B lymphocytes, eosinophils, basophils, mast cells
