Haemostasis Nd Platelet Flashcards
Thrombosis is what
Inaccurate coagulation leading to excess bleeding
Blood coagulation has how many phase and what are they
Vascular phase
Platelet phase
Coagulation cascade
Endothelin is a hormone secreted by to do what
Secreted by endothelial cells lining the inner wall of blood vessels
Platelet phase are
3
Adhesion
Activation
Aggregation
What is the adhesion stage of platelet
It is when platelet stick to ruptured blood vessels through glycoproteins
Plasmin is responsible for
The asymmetrical degradation of fibrin
Characteristics of platelet
Non non nucleated
Colorless
Actiavated platelets possesses
Filopodia that is tail
While the inactivated ones has no tail
Cell membrane of platelets contains
1)Glycoproteins: they prevent the stickyness of platelets to normal endothelium but speed up the adhesion to collagen and damaged endothelium
2) phospholipid: this accelerates the clotting reaction
Tubulin does what to platelet
Tubulin helps platelet to maintain its disc shape when inactivated
Platelets count in high altitude
Increases
Properties of platelet
Adhesion
Aggregation
Agglutination
What is the adhesive nature of platelet
When platelet comes in contact with the collagen outside of our blood vessels they become activated and stick
What stimulates the platelet to stick to the ruptured endothelium
Von willebrand factor
Von willebrand factor is secreted by
Ruptured endothelium
Von willebrand disease
A condition of excess bleeding due even in mild injury due to deficiency of Von willebrand factor which causes the adhesion of platelet to damaged blood vessels
Aggregation of platelet is
When the activated platelet develops filopodia and start sticking to one another at a particular site
Aggregation of platelet is activated by
ADP
secreted by glycoproteins in the cell membrane of platelet
Agglutination is
Clumping of platelet
Activators of platelet
Collagen
Von willebrand factor
ADP
Thrombin
Calcium ions
Thromboxane A2
Inhibitors of platelet
Nitric oxide
Prostacyclin
Clotting factor 2,9,10,11 and 12
Platelet are formed at
Bone marrow … colony forming megakaryocytes
Stimulating factor of platelet production is
Thrombopoetin and CSF
Thrombocytopenia is
Reduced platelet count
Thrombocytosis
Increase platelet count
Thrombocythemia
Abnormal and persistent increase in platelet count
Lifespan of platelet is
10days
Platelet are destroyed where
Spleen
Splenomegaly( increased sizes of spleen)… decrease platelet
Splenectomy( removal of spleen) increase platelet
Hemostasis
Stoppage of blood
What glycoproteins causes aggregation of platelet
Activated platelet secretes THOMBOXANE A2 and ADP
Stages in blood clotting
Formation of prothrombin activator
Conversion of prothrombin into thrombin
Conversion of fibrinogen to fibrin
Clotting factor 1
Fibrinogen
Clotting factor 2
Prothrombin
Clotting factor 3
Thromboplastin
Clotting factor 4
Calcium
Clotting factor 5
Labile factor
Clotting factor 7
Stable factor
Clotting factor 8
Antihemophilic factor
Clotting factor 9
Christmas factor
Clotting factor 10
Struat prower factor
Clotting factor 11
Plasma thromboplastin antecedent
Clotting factor 12
Hageman factor ( contact factor)
Clotting factor 13
Fibrin stabilizing factor ( fibrinase)
Stages in the Instrinsic pathway to formation of prothrombin activator
Contact factor( factor 12) comes in contact with collagen and become activated
Activated factor 12 activates factor 11
Activated factor 11 will now activate factor 9 ( IN THE PRESENCE OF FACTOR 4 which is calcium)
Activated factor 9 activates factor 10 with factor 8 + factor 4( calcium)
Activated factor 10 will come in contact with phospholipid and factor 5 to form PROTHROMBIN ACTIVATOR
Prothrombin activator does
Conversion of prothrombin to thrombin
Thrombin does
Activates fibrinogen and
Conversion of fibrinogen to fibrin
Define blood clot
Is a mass of entrapped RBC WBC AND PLATELET in a fibrin mesh work
Fibrinolysis is
The dissolution of fibrin inside the lumen of the blood vessels
Fibrinolysis is done by what protein
Plasmin
Plasmin production is stimulated by
Thrombomodulin
Secreted by Endothelium after intravascular clotting
What are anti coagulant
They prevent or postpone clotting of blood
A natural anti coagulant is
Heparin
What is thrombosis
Coagulation of blood inside the blood vessels
What is haemophillia
Prolonged clotting time due to a defect in the gene that codes for the protein that clots wound leading to increased bleeding time
Purpura
Prolonged bleeding time
Each megakaryocytes gives rise to
1000-5000 platelet
Megakaryocytes differentiate in the bone marrow in a site called
Osteoblastic niche
Megakaryocytes differentiate by
Endomytotic synchronous replication
This is where the cytoplasm volume increases Without dna replication
Normal platelet count is
100-300*10^9/L
Platelets are able to adhere to collagen due to
A glycoprotein called GpIa
What glycoproteins are important for platelet to bind to Von willebrand factor
Glycoproteins IIb and IIIa
Reason for no adhesion and aggregation of platelet to normal blood vessels walls is
Due to secretion of prostacyclin( high gmp) and nitric. Oxide