ANP 1115 - Blood (Pt. 2) & Intro to Heart Flashcards
(78 cards)
What is Fibrinolysis?
Removal of clot when no longer needed
What is the Key enzyme for Fibrinolysis?
Plasmin (precursor is plasminogen - plasma protein that gets incorporated into the clot)
- Plasminogen is the inactive form of plasmin
- Plasmin breaks down blood clot
What is Plasminogen Activated by?
Activated by tPA - Tissue Plasminogen Activator
- released by endothelial cells
When does Fibrinolysis begin and end?
Begins within 2 days and continues until clot is dissolved
What are the two Homeostatic Mechanisms to Control Size of Clot?
- Swift removal of coagulation factors
- Inhibition of activated clotting factors
What does Clot Formation Require?
Requires [procoagulation factors] > [anticoagulation factors]
What is the Importance of Vascular Spasms in response to Injury?
flowing blood washes away procoagulants
- Vascular spasms cause vasoconstriction, hence decrease in blood flow to maintain [procoagulants]
What happens to Thrombin as it is formed?
As thrombin forms, it is adsorbed onto fibrin threads (limits clot size)
What is the Role of Antithrombin III?
antithrombin III (plasma protein) inactivates any escaping thrombin
- antithrombin III & protein C (plasma protein) inactivate many intrinsic pathway procoagulants
What is Heparin and its Role?
basophils & mast cells
- enhances activity of antithrombin III and inhibits intrinsic pathway
What does Smooth Endothelial Lining of undamaged blood vessels prevent?
prevents undesirable clotting
- no access to collagen
- endothelial-derived NO & prostacyclin
What is a Thrombus?
A clot that develops and persists in an unbroken blood vessel
- can block critical blood circulation to those tissues
What might promote Thrombus formation in an unbroken blood vessel?
What is an Embolus?
A thrombus which ha broken free
- can get stuck in a vessel of small diameter
e.g., pulmonary or cerebral emboli
How do you treat a Thrombus?
Treat with drugs such as tPA, streptokinase to dissolve clots via plasmin
Why is a low does of Aspirin a good Preventative Therapy in heart attack risk patients?
Aspirin interferes with the production of prostaglandins
- Low dose because you still need blood clotting
- Preventative measure
What are the Three Bleeding Disorders?
- Thrombocytopenia
- Impaired Liver Function
- Hemophilias
What is Thrombocytopenia?
Any condition harmful to bone marrow (malignancy, radiation, drugs)
- Interference with normal levels of production of platelets
- Easy bruising due to internal hemorrhage
- Petechiae: tiny area of damage to capillary
What is Hemorrhage?
Escape of blood from a ruptured blood vessel?
Why does Whole Blood Transfusion only give TEMPORARY relief for Thrombocytopenia?
Platelet life span is only 10 days
What are some Impaired Liver Functions?
Hepatitis, cirrhosis (procoagulants come from liver)
- Liver disease also associated with reduced bile production
- Bile is required to absorb vitamin k
What is the Role of Bile?
Assists with digestion of fats in GI system
What is Hemophilias?
Hereditary bleeding disorders due to deficiencies in intrinsic pathway factors
What is the Difference between Hemophilia A and Hemophilia B?
Hemophilia A (83% of cases): lack factor VIII
Hemophilia B: lack factor IX
- both sex-linked and require regular transfusion