Leukocytes pt 2 Flashcards
____ play important roles in
maintaining the integrity of blood
vessels
Platelets
T/F: RBCs are larger than WBCs
False; WBCs are larger
Describe the characteristics of a Monocyte nucleus + cytoplasm
–kidney-shaped or U-shaped (bean-shaped)
–large indented nucleus
–Abundant, gray-blue/lavender
cytoplasm
Do monocytes live longer in the bloodstream or tissues?
Tissues; Lifespan in tissue several
months (make it a long term immune cell). Present in bloodstream 2-3
days.
T/F: Fixed tissue macrophages remain in same tissue
True
–First recognized in Bursa of Fabricius of birds
–In mammals, formed in bone marrow & become
immunocompetent there
B-cells
(Thrombopoiesis) Megakaryoblasts undergo _____ (DNA replication without
karyokinesis or cytokinesis
endomitosis
–Also function in Ab-dependent, cell-mediated
cytotoxicity (ADCC)
–Responsible for nonspecific cytotoxicity against virus-infected & tumor cells
Null Cells–Natural Killer Cells (NK)
–Help initiate immune response & defend body against
pathogens
–True ‘cells’ with nucleus & organelles
WBCs
Deficiencies in thrombopoietin cause
_______
thrombocytopenia
–Up to three times the diameter of an
erythrocyte
–Constitute about 3–8% of all
leukocytes
Monocyte
Fourth step of hemostasis: Platelet procoagulant activity
involving _____
thrombin
T/F: Receptors for the macrophage-stimulating factor (M-CSF) are restricted to
the monocyte lineage
True
HLA = human leukocyte Ag—major
histocompatability complex [MHC] molecules
REVIEW
Azurophilic Granules of monocytes and lymphocytes
1’ granules
↑ neutrophils indicate
acute inflammation, bacteria
Primitive cells of lymphocytes
lymphoblasts
3 Types of T-cells
Cytotoxic, suppressor & helper lymphocytes
_____ are highly phagocytic; Capable of continuous lysosomal activity and phagocytic
Monocytes
B-cells have HLA Type II Surface Markers and surface ____
immunoglobulins
Which is most common lymphocyte?
Neutrophil
(never let monkeys eat bananas)
are involved in
bacterial
phagocytosis,
antigen presentation,
and clean-up of dead
cell debris
macrophages
Fixed Tissue Macrophages: Also function as _____ in lymphoid
organs
Ag-presenting cells
B cells function in ______
immune response
humorally mediated
immune response—produce
Ab’s
megakaryoblast give rise to megakaryocyte. These cells form
____ which fragment into
platelets
platelet demarcation channels
T-Cells also have _____ determinant molecules on surface–recognize HLA receptors on surface of other cells
“cluster of differentiation” (CD molecules)
–1’ effectors in cell-mediated immunity (tend to be
large lymphocytes)
–Recognize cells with foreign surface Ag’s or receptors & kill them
–Punch holes in plasma membranes
Cytotoxic or killer t-cells (Tc/Tk)
Monocytes circulate in blood for 12
to 100 hours and then enter the
_____
connective tissue
Agranulocytes contain _____ primary granules only
Lysosomal-type
Fixed Tissue macrophages: Kupfer cells in
liver
–Central role in immunological defense
–Develop initially in the bone marrow
Lymphocytes
Second step of hemostasis: Platelet aggregation by binding to
____
fibrinogen
Megakaryoblast–>megakaryocyte–>_____ –>
platelet (thrombocyte)
proplatelet
–Detect invaders, sound chemical alarm
–Recognize Ag,
usually presented by macrophages or b-cell, then secrete
lymphokines (cytokines)
Helper T-Cells (Th)
B-cells have _____ surface markers and surface immunoglobulins
HLA Type II Surface Markers (tell if cell belongs to you or not)
Thrombopoiesis: Begin with precursor cell, the _____
megakaryoblast
Most macrophages are highly mobile, phagocytic—
contain _____
abundant hydrolytic enzymes
Specific granules are ___ granules
2’ (take most of stain)
Lymphocytes which possess Fc receptors but
lack specific cell surface markers of either b- or
t-cells
Null cells
–manage and direct an immune response
–some directly attack foreign cells and virus-infected cells
–Mature in the thymus
T-Lymphocytes (t-cells)
B-cells Function in ____ response of humoral immunity
anamnestic
↓ in WBC’s indicate
immune suppression/ tumor,e.g.,
-penia
Monocyte: Under the influence of a specific CSF (colony-stimulating factor), each precursor cell establishes its
own ____
hierarchy
Parasites are associated with what type of WBC
eosinophil
First step of hemostasis: Platelet adhesion to the
_____ matrix
subendothelial
Thropoietin is produced in the ____, has a similar
structure to erythropoietin.
liver
Result of Leukocyte adhesion deficiency I & II
No migration into Connective Tissue (more wbc in blood than expected)
–Immune cells fail to bind to blood vessel wall; can’t reach site of injury
Fixed Tissue macrophages: microglial cells in ____
CNS
Granulocyte-macrophage colony-stimulating factor (GM-CSF) guides the
monocyte precursor cell into the ____ pathway
monoblast
Increase in immature
granulocyte precursors (band
cells,
metamyelocytes,
myeloblasts) is called
a ____
‘left shift’
↑ lymphocytes (& monocytes)
subacute, viral
Cell adhesion proteins play a significant role in immune
surveillance, _______ & tumor metastasis
wound healing
Explain Macrophage’s role in antigen presentation
Can identify & present to lymphoid organs (ramp up immune system)
osis mononucleosis
“disease” increased wbc
Fixed Tissue macrophages: dust cells in
lung
Active in subacute to chronic infections, along with lymphocytes
Monocytes
Describe Agranulocytes nucleus + cytoplasm
–round or indented nucleus “bean”
–Non-lobulated nucleus
–variable (often
slight) cytoplasm
Helper T-Cells: Recognize Ag,
usually presented by macrophages or b-cell, then secrete
_____—act as pheromones, stimulate b-
cells => Ab production, or Tk cells => kill
lymphokines (cytokines)
stimulated to become plasma cells and
produce antibodies
B-lymphocytes (B-cells)
Loss of control of Ts cells can lead to
Autoimmune disease
↑ WBC’ can indicate
infection, tumor (problems)
Most ____ are highly mobile, phagocytic—
contain abundant hydrolytic enzymes
macrophages
T-cells have receptors on cell surface like those present on Ab’s (____). Recognize foreign proteins of Ag’s
(_____)
paratopes. epitopes
B-lymphocytes are stimulated to become ___
plasma cells
Fixed Tissue macrophages: osteoclasts in
bone
Platelet activation during
hemostasis involves sequentially:
1.Platelet adhesion to the
subendothelial matrix
’ 2.Platelet aggregation by binding to
fibrinogen
’ 3.Platelet secretion of substances
present in the granules, to recruit
additional platelets
’ 4.Platelet procoagulant activity
involving thrombin
continued reduction in demand> supply
Cytopenia
Monocytes: From the bloodstream, they enter the connective tissue to become ____
macrophages
Thrombopoiesis is regulated by ____
thrombopoietin
WBC enter the connective tissue via
homing mechanism
T/F: One of the main events in allergic inflammation is the
recruitment of inflammatory cells into tissue sites where allergic
reactions occur
True
In the connective
tissue, _____
differentiate into
macrophages
monocytes
WBC leave bloodstream via
diapedesis
Granulocyte-macrophage colony-stimulating factor (GM-CSF) guides the
monocyte precursor cell into the monoblast pathway, leading to the
production of peripheral ___ monocytes and tissue _____
blood monocytes and tissue macrophages
Malignant & pre-
malignant disease of
WBCs can lead to _______
circulating abnormal
cells (leukemia)
Lymphocyte maturation (3 stages)
lymphoblasts –> prolymphocytes –> lymphocytes
Monocytes derive from the granulocyte-macrophage CFU
Myeloid progenitor
Where does T-cell maturation occur?
Thymus
1’ cell of immune system—
recirculating, immunocompetent cells
Lymphocytes
Platelets bind and degrade
______, a process that
autoregulates platelet production.
thrombopoietin
After encountering Ag, undergo multiple divisions to produce
clone of Ab-producing plasma
cells–this is called
amplification, or clonal expansion
Differential cell count—
relative percentages of WBC’s
B-Cells: After encountering Ag, undergo multiple divisions to produce
_____
cells
clone of Ab-producing plasma
Platelets bind and degrade
thrombopoietin, a process that
_______ platelet production.
autoregulates
anamnestic response
renewed rapid
production of an antibody following second or later
contact with the provoking antigen
Plasma cells produce _____
antibodies
Suppress activity of b-cells, dampen immune response,
especially to “self” molecules
Suppressor T-cells (Ts)
Third step of hemostasis: Platelet secretion of substances
present in the granules, to _____
recruit
additional platelets
Neutropenia can lead to ?
acute viral infection or severe sepsis ?
–Formed in bone marrow, but migrate to thymus to become *immunocompetent
–Responsible for cell-mediated immunity; have long lifespan
T-Cells
Responsible for nonspecific cytotoxicity against virus-infected & tumor cells
Null Cells–Natural Killer Cells (NK)
megakaryoblast gives rise to the ______.
–These cells form
platelet demarcation channels which fragment into
platelets
megakaryocyte
What is leukocytosis?
increase in the number of
leukocytes in blood
Monocytes: Can fuse together to become (multinucleate) ______ in chronic granulomas
epithelioid giant cells
An excess of thrombopoietin causes
_____
thrombocytosis (increased platelet count)
Granulocyte colony-stimulating factor (G-CSF) takes the granulocyte precursor cell into the ______ pathway
myeloblast
–Most found in lymphatic tissue
–20-25% of total number of
circulating leukocytes
–Round nucleus that
occupies most of the cell
–thin sliver of cytoplasm visible
–may live for a
few days or several years
–densely staining nucleus surrounded by thin
rim of cytoplasm
Lymphocytes
Most common type of Lymphocyte
T-cell (t-cell 90%, b-cell 10%)
“extravasate”
flow out of vessels and enter tissues
Lymphocytes: Active in ____ to ____
infections
subacute to chronic
infections
2 types of Agranulocytes (or
Mononuclear leukocytes)
monocytes & lymphocytes
leukocytes that have such small
granules in their cytoplasm that they are frequently
overlooked upon casual observation
Agranulocytes
–Filled with hydrolytic enzymes
–Present in bloodstream 2-3
days, then extravasate, enter
tissue, become macrophages,
Mj (= histiocytes)
Monocytes
Some b- & t-cells do not replicate, but remain as
____ cells or _____ cells
long-lived memory cells or effector
Fixed Tissue macrophages: Langerhans cells in
skin
Lymphocytes constitute a _____ population of
cells that differ from each other in terms of origin, life
span, preferred sites of localization within lymphoid
organs, cell surface markers, and function
heterogeneous
B-cell maturation. Occurs in the bone _____
Bone marrow–humans
bursa of Fabricius–birds
transient reduction in N# can occur due to cytokines in early viral infections
Neutropenia
total # of RBCs & WBC’s
CBC (complete blood count)
thrombocytopenia—
↓ platelets (harder time clotting)
Two classes of Lymphocytes:
Small and Big
-penia
decrease
Monocytes–Produce & secrete & have
receptors for chemical aka good at
signaling others/getting help (mediators)
Null cells: Lymphocytes which possess ______ but
lack specific cell surface markers of either b- or
t-cells (null)
Fc receptors
______ (15 to 80 μm in diameter) constitute a
population of emigrated blood monocytes that differentiate
in tissues (in response to local conditions
Macrophages
T-cells recognize ____ on surface of other
cells (prevent “self”-destruction)
HLA receptors
What do null cells lack and what is the consequence?
possess Fc receptors but
lack specific cell surface markers of either b- or
t-cells (null); attack anything–no memory
↑ eosinophils indicate
allergies, parasites
Mature B&T cells leave the marrow & thymus to
circulate and to establish l_____ in the
spleen, lymph nodes and within the gut tube.
lymphocyte colonies
Thropoietin stimulates the development of megakaryocytes from the _____ into platelets
megakaryocyte CFU
