Hemostasis Disorders and Anti-Coagulants Quiz

Hemostasis Disorders

• Hemostasis is the stoppage of bleeding and clot formation.
• Key components of hemostasis are platelets.
• Platelets originate from megakaryocytes in bone marrow.
• Thrombopoietin is a hormone that regulates platelet maturation and proliferation.
• Platelets have a lifespan of 8-9 days.
• Platelet count in blood is 150,000-400,000/µL
• Platelets structure includes: glycocalyx coat (glycoproteins), cell membrane, hyalomere (micro tubules & micro filaments, actin, & myosin), and granulomere (mitochondria, synthesis of ATP, enzymes, granules).
• Granules contain glycoproteins, fibrinogen, growth factor, plasmin, ADP, and serotonin.

Anti-Coagulants

• Anti-coagulant drugs are used to prevent thromboembolic disorders such as DVT/pulmonary embolism.
• Heparin is extracted from animal tissues. Acts fast but not prolonged.
• Warfarin is given orally and has a prolonged action of 36-72 hours.
• It alters vitamin K and pro-coagulation factors.

Clot Retraction

• Happens after clot formation (20-60 minutes).
• Clot retraction is facilitated by actin and myosin.
• It squeezes serum from the clot.
• Joins edges of broken vessels.
• Requires a certain number of platelets.
• Failure of clot retraction indicates a problem with platelet count.

Causes of Thrombocytopenia

• Decreased platelet production (bone marrow failure).
• Decreased platelet survivial (autoimmune disorders & anti-platelet antibodies).
• Bone marrow depression (chemotherapy, some viral infections.)
• Splenic sequestration
• Dilutional thrombocytopenia (massive blood/plasma transfusion).

Clot Formation

• Vessel spasm is the initial response to injury(less than 1 minute).
• Neural reflexes, hormones, and vasoconstriction factors are involved.
• Platelets adhere to damaged areas.
• Platelet adhesion, activation, degranulation, and aggregation occurs.
• Platelets release factors that activate the coagulation cascade,
• Conversion of fibrinogen to fibrin forms a stable clot.

Coagulation Disorders

• Hemophilia A is an X-linked recessive disorder that impairs normal blood clotting due to affected factor VIII gene.
• This can result in excessive bleeding and difficulty in clot formation.

Vitamin K Deficiency

• Vitamin K is essential for synthesis of clotting factors.
• Impaired intestinal synthesis or absorption of vitamin K can lead to deficiency.
• Infants and those using broad-spectrum antibiotics are at risk.
• Liver, or gallbladder diseases can impair fat absorption.

Test your knowledge on hemostasis disorders and the mechanisms of anti-coagulant drugs. This quiz covers the key components of hemostasis, the role of platelets, and various anti-coagulant medications like heparin and warfarin. Challenge yourself and understand the complexities of blood clotting and its regulation.