Ch. 18 Flashcards
Blood
What is the average blood volume in humans?
70 mL per kg of body weight
What is the between plasma and serum?
Serum lacks fibrinogen and other coagulation factors
What is the normal amount of hematocrit in men vs women?
Women: 38-42%
Men: 40-44%
Calculate Hematocrit
Hematocrit = height of RBCs/ total height
What is the source of most blood cells?
Bone Marrow
What cells are produced from megakaryocyte-erythroid progenitor cells?
Megakaryocyte, platelets, and RBCs
What is necessary for the production of RBCs?
EPO
What is necessary for the production of platelets?
TPO and IL11 are required to produce megakaryocytes, which produce platelets
How does renal failure effect RBC development?
JG (which senses oxygen) does not function, so EPO levels don’t rise correctly in response to low O2 levels; results in anemia
Coagulation
the cessation of bleeding
Anticoagulation
limiting the extent of coagulation so you don’t get blood clots
Fibrinolysis
clot lysis
What are the 4 methods by which hemostasis can be achieved?
- Vasoconstriction
- Increased tissue pressure
- Formation of a platelet plug in the case of capillary bleeding
- Coagulation or clot formation
What are the 3 A’s of Platelet Function?
Adhesion
Activation
Aggregation
How are platelets involved in primary hemostasis?
At the site of vessel injury, they adhere by GP1b and vWF (Adhesion). They get activated by a number of receptors that leads to signaling for recruitment of other platelets, then form complexes on their surfaces to have platelet-platelet interactions that causes aggregation (Activation). Eventually they form a big glob of platelets that forms a platelet thrombus.
Know the Coagulation Cascade
How’d you do?
Disorders of the intrinsic system
Associated with bleeding: VIII, IX, XI
Not Associated with Bleeding: XII, HMWK, Prekallikren
Surface Bound Zymogens
Factor XII, Prekallikrein, Factor XI
Phospholipid Bound Zymogens
Factors II, VII, IX, and X
Cofactors/Substrates
HMWK, Factors V and VIII, Tissue Factor, and Fibrinogen
Activated Partial Thromboplastin Time (APTT)
Measures intrinsic and common pathways
Prothrombin Time
measures extrinsic and common pathways
Thrombin Time
measures transition from fibrinogen to fibrin
Tenase
necessary to make factor Xa
Prothrombinase
necessary to convert prothrombin (II) to thrombin (IIa)
Protein C/Protein S System
inactivates factors Va and VIIIa (cofactors for prothrombinase and tenase, respectively)
Antithrombin
inhibits many factors, but main effect is on IIa and Xa
Tissue Factor Pathway
inhibits VIIa and Xa
What are 3 high risk defects associated with Venous Thrombosis?
Protein C, Protein S, and Antithrombin
