Unit 6.2 PLATELET STUDIES Flashcards
(50 cards)
are produced from the cytoplasm of megakaryocytes
Platelets
Despite their tiny size, they are complex and metabolically active.
Platelets
They function in hemostasis by interacting with their environment to initiate and control hemostasis
Platelets
General characteristics of thrombocytes:
• Shape & origin:
• Diameter:
• Reference platelet count:
• Daily turnover:
• Lifespan:
• Function:
Thin disc cytoplasmic fragments
2 - 4 pm; Volume: 5 - 7 fL
150.000 - 450.000/uL
35 X 10%/L (+/- 4.3)
8 - 11 days
(Hemostasis) maintenance of vascular integrity and blood coagulation
bears the different glycoproteins
Glycocalyx
: Underlies the plasma membrane & receives message from the outside
Submembranous area
Peripheral zone:
Glycocalyx
Submembranous area:
Consists of a stable gel that regulates arrangement of internal organelles
Sol-Gel zone:
- provide the cytoskeleton
Microtubules & microfilaments
Where the alpha granules, dense bodies, mitochondria, lysosomes and peroxisomes are located.
Organelle zone:
2 membrane systems
Open canalicular system
Dense tubular system
- site of arachidonic acid synthesis and functions as a calcium sequestering pump
Dense tubular system
delivery routes
Open canalicular system
High Molecular Weight Kininogen Fibrinogen;
Promote coagulation
Factor V
Promote coagulation
von Willebrand Factor
Promote coagulation
Alpha granules
Promote coagulation
ADP;
Promote aggregation
Calcium
Promote aggregation
Platelet factor 4
Promote aggregation
Thrombospondin
Promote aggregation
Dense bodies
Promote aggregation
Alpha granules
Promote coagulation
Promote aggregation
Promote vasoconstriction
Promote vascular repair
Other system affected
Serotonin
Promote vasoconstriction
