VASCULAR AND PLATELET SYSTEM Flashcards
Production and development of megakaryocytes, the precursors to platelets, in the bone marrow
Megakaryopoiesis
Formation, production and development of blood platelets (thrombocytes)
Thrombopoiesis
specific hormone responsible for commitment of the megakaryoblast to differentiate further into more mature stages; primary regulator of thrombopoiesis;
stimulates differentiation and maturation of the megakaryocytes;
produced by the liver and kidneys
Thrombopoietin
Thrombopoietin is produced in
kidney and liver
a multipotent hematopoietic growth factor produced by activated T-cells, monocytes/macrophages and stroma cells
Interleukin 3
stimulates thrombopoietin production; promptly and transiently produced in response to infections and tissue injuries, contributes to host defense through the stimulation of acute phase responses.
Interleukin 6
together with TPO controls the production and release of platelets.
Interleukin 11
acts primarily on primitive cells of the hematopoietic cell lineages
preserve the viability of hematopoietic stem and progenitor cells, to influence their entry into the cell cycle and to facilitate their proliferation and differentiation
Stem Cell Factor
for proliferation of megakaryocytic progenitor cells
FLT-3 Ligand
inhibitors of hematopoiesis
TGFs & Interferon-gamma
Least mature progenitor
BFU meg
Most mature and enters endomitosis
LD CFU meg
is a form of mitosis that lacks telophase and cytokinesis
Endomitosis
Endomitosis lacks
telophase and cytokinesis
unique (Megakaryocyte ONLY) form of mitosis in which DNA replication and cytoplasmic maturation are normal but cells lose their capacity to divide.
Endomitosis
___ days for megakaryocytes to mature in the bone marrow
4-5
Most mature megakaryocyte are __N and __N
8N and 16N
Differentiating and mature megakaryocytes localize to the ______________ in preparation for movement into the bloodstream
abluminal (nonblood) surface of sinusoid-lining endothelial cells
largest megakaryocyte cell series
MK-III
Basophilic/Nongranular cytoplasm
MK-I
Indented nucleus
MK-II
3:1 N/C ratio
MK-I
endomitosis is present in
MK-I
endomitosis ends in
MK-II (promegakaryocyte)
a series of membrane-lined channels that
invade from the plasma membrane and grow inward to subdivide the entire cytoplasm & becomes the future site of platelet fragmentation
Demarcation Membrane System
With plasma membrane blebs, resembles platelets
Resembles the myeloblast and pronormoblast (rubriblast)
megakaryoblast or MK-I
CYTOPLASM
More abundant
Less basophilic
Promegakaryocyte/MK-II
No nucleoli, Pyknotic
Platelet-like
Megakaryocyte
Megakaryocytic cell series with highest percentage (55%)
MK III (Megakaryocyte)
Megakaryocytic cell with homogenous chromatin
Megakaryoblast
Megakaryocytic cell series with moderately condensed chromatin
Promegakaryocyte
Megakaryocytic cell series with 1:2 N/C ratio
Promegakaryocyte
lines the vessel wall and is antithrombotic: nonreactive to platelets and plasma proteins until damaged
Endothelium
Inhibits platelet activation
Stimulates vasodilation
Prostacyclin (PGI2)
Endothelial surface receptor for thrombin
Binds and inactivates thrombin
Enhances anticoagulant/fibrinolytic
action of protein C
Thrombomodulin
Coats the endothelial cell surface
A plasma anticoagulant
Heparan sulfate
Platelet adhesion to site of vessel injury
von Willebrand
factor (vWF)
Vasoconstriction is controlled by vessel smooth muscle, triggered by
- Reflexes by local pain receptors
- Serotonin
- Thromboxane A2 (TxA2)
Development of cytoplasmic granules and formation of DMS
MATURATION
Membranous system component that is involved in phagocytosis
surface-connected calanicular system
Platelets roll and attach to nonplatelet surface
1. Subendothelium collagen
2. fibrinectin
3. basement membrane
Platelet adhesion
platelet aggregation disorder that is deficiency in GP IIb/IIIa
Glanzmann thrombasthenia
Calcium promote aggregation. T or F?
T
________ inhibit
the activity of cyclooxygenase
(COX)
Aspirin and other NSAIDs
