Megakaryocyte & Platelets Flashcards
A complex process that involves the commitment of hematopoietic stem cells (HSCs) to the megakaryocyte (MK) lineage, proliferation of the progenitors, MK maturation and terminal differentiation that produces platelets
megakaryopoiesis
the hormone thought to stimulate the production and maturation of megakaryocytes, which in turn produce platelets, has recently been purified and cloned.
thrombopoietin
Thrombopoietin activity results from several different cytokines:
Erythropoietin, IL-3, and granulocyte-macrophage colony-stimulating factor (GM-CSF).
Size: 10-24 mm
Nucleus: Round
Nucleoli: 2-6
Chromatin: Homogeneous, loosely organized
Cytoplasm: Basophilic
Granules: Absent by Wright stain
N/C Ratio: 3:1
REFERENCE INTERVAL:
→ Bone Marrow: 20% of megakaryocyte
precursors in bone marrow
→ Peripheral Blood: 0%
megakaryoblast
Size: 15-40 mm
Nucleus: Indented
Nucleoli: Variable
Chromatin: Condensed
Cytoplasm: Basophilic
Granules: Present
N/C Ratio: 1:2
REFERENCE INTERVAL:
→ Bone Marrow: 25% of megakaryocyte
precursors in bone marrow
→ Peripheral Blood: 0%
promegakaryocyte
the largest bone marrow cells, ranging up to 160mm in size. The nuclear-cytoplasmic (N;C) ratio can be as high as 1:12.
megakaryocyte
T/F
Nucleoli are no longer visible.
T
Distinctive feature of the megakaryocyte
multilobular
Platelets have an average diameter of ____, with younger platelets being larger than older ones.
2-4mm
The cytoplasm is ____, with evenly dispersed, fine _____ granules
light blue (cytoplasm)
red-purple (granules)
An inactive or unstimulated platelet circulates as a ______
thin, smooth-surfaced disc
platelet surface glycoprotein 1b
GP 1b
significant in hemolysis process
GP IIb/IIa
PF4 meaning
platelet factor 4
potent mitogen responsible for cell proliferation
PDGG (Platelet Derived Growth Factor)
having multifunctional cytogenes
TGF-beta (Transforming Growth Factor Beta)
blood glycogen involving hemostasis; helps platelet to stick together so that if there is hemolysis, they will still stay together
VWF (Von Willebrand Factor)
aka fluffy coat
the glycocalyx
This surrounds the cellular membrane of the
platelet externally
the glycocalyx
Unique among the cellular components of the blood
the glycocalyx
Composed of plasma proteins and carbohydrate molecules that are related to the coagulation, complement, and fibrinolytic systems
the glycocalyx
Located directly beneath the cell membrane of platelet
Microfilaments & Microtubules
Provide the structure of the platelet to maintain its discoid shape
Microfilaments & Microtubules
Maintains the position of the organelles
Microfilaments & Microtubules
