Platelets and coagulation, bleeding and thrombotic disorders

What is haemostasis?

What are the four main systems involved in the prevention and arrest of blood loss?

What does haemostasis provide a balance between?

Starting with the vascular endothelium, list the layers of a blood vessel towards the outer aspect.

When exposed in the tunica media, what protein can activate haemostatic processes?

Under normal circumstances, what negative properties does blood have that are removed with damage?

Under normal circumstances, what negative properties does blood have that are removed with damage?

What are thrombocytes?

What is the range of thrombocytes per litre of blood found in humans?

What number of thrombocytes per litre of blood can exist without spontaneous bleeding?

What number of thrombocytes per litre of blood would be expected for spontaneous bleeding?

List the three zones of a platelet.

What does the outer zone of a platelet consist of and what is it's role?

What does the cytosol gel zone of a platelet consist of and what is its role?

What do the platelet organelles consist of?

Where does thrombopoiesis occur?

What do megakaryocytes, large cells in the bone marrow of 5000um3 in volume, not undergo?

What is endomitosis and what does it produce?

How many thrombocytes can be produced per megakaryocyte?

What chemical modulates thrombopoiesis and where is it produced?

The concentration of thrombopoietin in the blood is always the same. What is this concentration?

What does thrombopoietin do?

How does thrombopoietin act and how does it feed back to the liver and kidneys?

What do the platelet's alpha-granules contain?

What effect does serotonin have on blood vessels and why is it significant that it is present in platelet electron-dense granules?

What activates the open canalicular system of platelets?

What does the open canalicular system allow platelets to do?

In what situation is the coagulation system activated?

What composes the coagulation system?

What does the coagulation system 'aim' to produce?

The coagulation cascade is a sequence in which...

What is the first tissue factor to be activated in the coagulation system in both the intrinsic and the extrinsic pathways?

What are the second tissue factors activated in the intrinsic and extrinsic pathways of the coagulation system?

What is TFPI and what does it do?

Which tissue factor is produced in the extrinsic pathway?

What does factor VIII, along with PL and Ca2+, activate in the intrinsic pathway of the coagulation cascade?

Along with PL and Ca2+, what does factor Xa activate?

In what three ways can thrombin increase its own production earlier on in the coagulation cascade once a small amount has been produced?

What does thrombin catalyse the conversion of?

Once the fibrin monomers have joined to form a polymer, what happens?

What does the coagulation cascade occur on top of?

Thrombin feeding back to increase its own production, can amplify the thrombin concentration by how many times?

What are the two main roles of thrombocytes in haemostasis?

If the vascular endothelium is damaged or missing, what is exposed that results in platelet activation and induces the formation of a primary haemostatic plug?

What type of charge is lost if the vascular endothelium is missing or damaged?

What are the two main chemicals produced by the vascular endothelium in balance when it is healthy/not damaged?

What is von Willebrand's factor?

What is the function of thrombomodulin?

What is the major function of the fibrinolytic system?

What is the key proteolytic enzyme in the fibrinolytic system?

Outline the steps/factors in the fibrinolytic system.

What happens to the products of the degradation of fibrin by the fibrinolytic pathway?

List the three most important chemicals produced by the intact vascular endothelium that promote an anticoagulant environment and explain what they do.

If intact, what is the overall effect of the factors produced and inhibited by the vascular endothelium?

Disorders of haemostasis and coagulation are a result of one of two things. What are these?

What four things may disorders of haemostasis and coagulation involve?

What are the two, opposing, possible results of a haemostatic/coagulant disorder?

Can haemostatic/coagulation disorders be congenital or acquired?

What must therapy for haemostatic/coagulant disorders try to do?

List 4 systemic diseases that affect haemostasis.

Name two congenital haemorrhagic disorders of platelets and give a brief explanation of each of them.

List three inherited coagulopathies.

Which of the haemophilias is more common?

Two which chromosome are haemophilias A and B linked?

What are the two pathologies of haemophilia A?

What is likely to be the most striking clinical presentation of haemophilia A?

What is the correct term for haemorrhages around joints?

What is the actual result of haemophilia A (factor VIII deficiency)?

What is the treatment for haemophilia A in the event of trauma, which patients may also choose to administer prophylactically?

Can haemophilia B be distinguished from haemophilia A by clinical presentation?

What proportions of people with haemophilia B lack factor IX entirely or have a functionally defective protein?

What is the treatment for haemophilia B?

What is the result of the deficiency of von Willebrand's factor in pseudohaemophilia?

Generally, what do pseudohaemophilia patients present with as opposed to the haemarthritis seen in haemophilia?

What are pseudohaemophilia patients treated with in the event of episodic bleeding, trauma-induced life-threatening haemorrhage, or spontaneous bleeds?

Name two acquired coagulopathies.

What does 'petechiae' refer to?

What does 'purpura' refer to?

Why is disseminated intravascular coagulation (DIC) a coagulopathy rather than a thrombotic disorder?

Why is there a high risk of spontaneous bleeding in disseminated intravascular coagulation (DIC)?

In disseminated intravascular coagulation (DIC), thrombosis of small vessels is widespread. List four areas that frequently become populated with microinfarcts.

Name two conditions that DIC is often associated with.

Which blood clotting factors require vitamin K for their synthesis?

What is the result of the deficiency of blood clotting factors resulting from vitamin K deficiency?

Name two things that might result in vitamin K malabsorption.

Name two situations which may cause malnutrition and resulting vitamin K deficiency.

Why might chronic ingestion of oral antibiotics result in vitamin K deficiency?

What condition to do with the liver/gallbladder can cause vitamin K deficiency, as well as the deficiency of other fat-soluble vitamins?

In thrombotic disorders, what kind of environment is an individual's blood/circulatory system?

What is thrombocytosis?

What is thrombocythaemia?

What conditions might thrombocythaemia be associated with?

What is thrombocytopenia?

What happens in idiopathic thrombocytopenic purpura (ITP)?

What can thrombocytopenia be caused by?

What is thrombotic thrombocytopenic purpura (TTP) characterised by?

What is the difference between idiopathic thrombocytopenic purpura (ITP) and thrombotic thrombocytopenic purpura (TTP)?

What is thrombophilia?

What can inherited thrombophilia be a result of?

What is the function of anti-thrombin III?

Why would lack of anti-thrombin III result in thrombophilia?

What is it called when thrombi travel and lodge?

Why would protein C deficiency result in thrombophilia?

What is there a high risk of if fibrin production is not inhibited?

What is venous thromboembolism?

What does venous thromboembolism commonly occur after?

Even if the fibrinolytic system is activated, how might venous thromboemboli still occur?

How does a pulmonary embolism result from a venous thromboembolism?

What is the result of a pulmonary embolism and what are the common clinical symptoms?

Give some examples of acquired thrombophilia.