Leukocytes Flashcards
what part of the blood do leukocytes make up
the buffy coat
how do leukocytes leave circulation
margination, pavementing, and diapedesis
how do WBCs travel through capillaries and venules
they stick to the endothelial cell surface and squeeze between the capillaries and venules with psuedopodia
what is the function of leukocytes
immune response
how are WBCs categorized
granulocytes and agranulocytes
what are primary granules
azurophilic granules, they stain blue-purple and contain lysosomal enzymes
what do secondary granulocytes contain
lysozyme and alkaline phosphatases
what are the types of granulocytes
neutrophils, basophils, and eosinophils
describe the appearance of granulocytes
single, multi lobed nucleus and prominent cytoplasmic granules
describe neutrophils
multi lobed nucleus, polymorphonuclear cells, most common, short lived
how do neutrophils obtain energy
through primary anaerobic glycolysis
what do primary granules in neutrophils contain
antimicrobial myeloperoxidase
what do neutrophils contain
inflammatory mediators and complement activators, proteases, defensins, lactoferrin, and lysozyme
what do tertiary granules in neutrophils contain
gelatinase
what type of inflammation are neutrophils involved with
acute
what is the main function of neutrophils
phagocytosis that leads to formation of phagolysosome to digest bacteria
what is a respiratory burst
bacterial killing by generating hydrogen peroxide and hypochlorous acid
what are stab cells
(band cells), immature neutrophils, can indicated chronic infection and be identified by an underdeveloped nucleus
what is a barr body
inactive X chromosome in females, can be identified by looking like a “drumstick”
describe basophils
least common, bilobed nucleus, mast cells are the same thing, characterized by large, basophilic specific granules
describe the appearance of mast cells
look comma shaped and have granules
what do specific granules in basophils contain
hydrolytic enzymes, heparin sulfate, chondroitin sulfate, histamine, leukotrienes
what type of reactions would you see basophils involved in
asthma, hayfever, and some types of allergic dermatitis
what counteract the effects of basophils
eosinophils
what color do eosinophils stain
red
describe the appearance of eosinophils
bilobed nucleus
what type of surface receptors do eosinophils have
IgE
what do eosinophil specific granules contain
histaminase, eosinophil peroxidase, lysosomal enz’s, major basic protein
what attracts eosinophils to basophils and mast cells
eosinophilic chemotactic factor (ECF)
what roles do eosinophils play
important in hypersensitivity reactions to counteract effects of basophils and have antiparasitic function
what are the 2 types of agranuloctyes
monocytes and lymphocytes
describe agranulocytes (general)
single, unlobed nucleus
- lack secondary granules but have primary azurophilic granules
what is the largest WBC
monocytes
describe the appearance of monocytes
-nucleus is bean shaped and blue/lavender in color
- large cytoplasm
what do monocytes become when they enter tissue
macrophages
what is the lifespan of monocytes in tissue
several months
what are examples of fixed tissue macrophages
kupfer cells in liver, microglial cells in CNS, langerhans cells in skin, dust cells in lungs, and osteoclasts in bone
describe macrophages
highly mobile, phagocytic, contain abundant hydrolytic enzymes
when are macrophages active
in subacute to chronic infections
what do macrophages fuse together to become
giant cells
what do monocytes/macrophages do in lymphoid organs
function as antigen presenting cells
when are lymphocytes active
in subacute to chronic infections, viral infections
what is the lifespan of lymphocytes
days to years
describe the appearance of lymphocytes
round, densely staining nucleus surrounded by thin rim of cytoplasm
what are the types of lymphocytes
b cells and t cells
where are B cells formed and where do they mature
formed in bone marrow and become mature in bone marrow
what do B cells function in
humorally mediated immune response to produce antibodies
what is amplification/clonal expansion
beta cells undergo multiple divisions to produce clones of antibody producing plasma cells after encountering an antigen
why do B cells look lopsided
antibodies are stored in the cytoplasm
theyre “pregnant”
what are B cells that do not replicate known as
memory cells
where are T cells formed and where do they mature
formed in bone marrow but mature in thymus
what are T cells responsible for
cell-mediated immunity.
-they have paratopes (receptors) that recognize epitopes (foreign proteins of antigens)
- they have CD molecules that prevent self destruction
what are the types of T cells
cytotoxic, suppressor and helper lymphocytes
what do cytotoxic/ killer T cells do
recognize cells with foreign surface antigens or receptors and kill them by punching holes in plasma membranes
what do helper t cells do
detect invaders, recognize antigens presented by B cell or macrophage then secrete lymphokines that act as pheromones to B cells for antibody production or to killer T cells to kill them
what do suppresor T cells do
suppress activity of B cells, dampen immune response
what are null cells
lymphocytes that possess Fc receptors but lack specific cell surface markers of either b or t cells
what is an example of null cells
natural killer cells
what are null cells responsible for
- nonspecific cytotoxicity against virus infected and tumor cells
- antibody dependent cell mediated cytotoxicity
what is the mnemonic to remember relative concentrations of WBCs
Never Let Monkeys Eat Bananas
what is a CBC
total number of WBCs
what would an increase in WBCs tell you
infection/tumor
- increased neutrophils, lymphocytes, eosinophils
what would a decrease in WBCs tell you
immune suppression/tumor
- neutropenia
-decrease in platelets
