The Thrombon Flashcards
What is hemostasis?
stoppage of blood loss from an injured blood vessel
Define vascular spasm:
vessels shrink to prevent blood leaks
What is a platelet plug?
when platelets stick together around a wound to patch a leak
What causes clot formation?
coagulation proteins, platelets, Ca2+, tissue factors
What are the 5 main steps of platelets forming a hemostatic plug?
Adherence
Shape change
Secretion
Aggregation
Contract
How long does platelet production take place?
4-5 days
What is the circulation time of a platelet?
7-9 days
What is the lifespan of platelets?
10 vdays
The major determinant of platelet density is based on the
alpha granules of the platelets
PF-1 =
Factor V
PF-2 =
anti-ATIII
PF-4 =
neut & monocyte chemotactic factor & anti-heparin
PF-5 =
Fibrinogen
PF-6 =
Antiplasmin
Beta-thrombospondin binds
fibrinogen
Beta-thromboglobulin impedes
PGI2 production by the endothelium
Fibronectin is…
an adhesin in wound healing
aka opsonin
vWF/Factor I are binding proteins for
adhesion/cohesion
Define emperipolesis.
The active penetration of one cell by another which remains intact
What diseases of the thrombon are possible?
- Thrombocytopaenia
- thrombocytopathies
- thrombocytosis
- primary bone marrow disease
- reactive
- essential thrombocytosis
What are some clinical signs of thrombocytopaenia?
- prolonged bleeding after a minor cut or wound
- bleeding defect in newborns
- access to poisons
- purpura
- bleeding into body cavity, muscle, eye
- decrease in platelet numbers
What are the 3 mechanisms of thrombocytopenia?
- Deficient production
- Accelerated destruction or loss
- abnormal pooling
Viremia infection causing thrombocytopenia is often…
M3 hyperplasia of bone marrow megakaryocytes
Rickettsial infection causing thrombocytopenia often causes…
- stem-cell suppression or myelofibrosis
- splenic sequestration
- consumption due to vasculitis
Babesia canis leading to thrombocytopenia casues…
hepatic &splenic sequestration due to hepatosplenomegaly
Other specific causes…
