| Question |
Answer |
| What is hemostasis? |
The stoppage of bleeding or hemorrhage. |
| What are the components of hemostasis? |
Blood Platelets, Endothelial Cells, Plasma Coagulation Factors |
| What are the steps involved in hemostasis? |
1. Compression and Vasoconstriction 2. Formation of a platelet plug 3. Blood Coagulation 4. Clot retraction and thrombus dissolution |
| What is the purpose of vascular spasms? |
Reduces blood flow and blood loss |
| What are the stepsw involved in the formation of a platelet plug? |
1. Adherence - binding of receptor platelets 2. Aggregation - Platelets stick to collagen fibers 3. Secretion - releases ADP, thromboxane, and collagen |
| What plays a role in clot formation as well as clot dissolution? |
Thrombin |
| What organ is primarily responsible for the formation of coagulation factors? |
Liver |
| Where do thrombocytes originate from? |
From megakaryocytes in the bone marrow |
| What vitamin is required for the activation of some coagulation factors? |
Vitamin K |
| How long does it take for the formation of a blood clot to begin in a severe trauma? |
15-20 seconds |
| How long does it take for the formation of a blood clot to begin in a minor trauma? |
1-2 minutes |
| What is the clot initiated by? |
Bllod proteins, and activator substanes from platelets and the vascualr wall |
| How long does it take for the clot to be formed? |
3-6 minutes |
| What time does clot retraction occur? |
20 min - 1 hour |
| What forms connective tisue within the clot? |
Fibroblasts |
| What is the size of platelets? |
2-4 micrometer |
| What is the half-life of a platelet? |
8-12 Days |
| What organ is primarily responsible for eliminating platelets? |
Spleen - by the tissue macrophage system |
| True or False, platelets contain a nucleus? |
False |
| True or False, platelets can reproduce? |
False |
| What is the surface of platelet cell membrane composed of? |
Glycoproteins - avoids sticking to the endothelium |
| What are procoaggulants? |
substances that promote coagulation |
| What are anticoagulants? |
substances that inhibit coagulation |
| What is the role of prothrombin activator? |
Catalyzes the conversion of prothrombin into thrombin |
| What does thrombin do? |
It acts as an enzyme to convert fibrinogen into fibrin fibers |
| True or False fibrinogen has a high molecular weight? |
True - 340,000 |
| True or False, platelets are necessary for clot retraction? |
True |
| Clotting factors are dependent on what vitamin? |
Vit K |
| List the types clotting factors? |
1. Prothrombin 2. Protein C 3. Factor VII 4. Factor IX 5. Factor X |
| How many pathways are there in the coagulation cascade? |
2, Extrinsic Pathway - Tissue Damage & Intrinsic Pathway - Endothelial damage |
| What is necessary for the activation of both pathways of the Coagulation Cascade? |
Phospholipids |
| What all is involoved in Clot retraction? |
1. Prostacyclin (PGI2) 2. Tissue Plasminogen Activator (TPA) 3. Plasmin 4. Thrombin 5. Protein C and its cofactor protein S 6. Antithrombin III 7. Heparin |
| True or False, Strokes and Embolisms are associated w/ abnormalities in Protein C and S, Antithrombin III, and Plasminogen? |
True |
| Name 3 causes of excessive bleeding? |
1. Vit. k deficeincy 2. Hemophilia 3. Thrombocytopenia |
| What is a thrombus? |
an abnormal clot that develops in the blood vessel |
| What is an emboli? |
A free flowing clot |
| What are the 3 causes of thromboembolic conditions? |
1. Roughened Endothelial surface of a vessel 2. slow flowing blood 3. DIC - Disseminated Intravascular Coagulation |
| What are the 2 types of anticoagulants? |
Heparin and Coumarins |
| What are the 3 types of Blood Coagulation Tests? |
1. Bleeding Time 2. Clotting Time 3. Prothrombin Time |
BIOL3326 Forms
