Term
Draw out the in vivo coagulation cascade
use acceptable nomenclature for the coagulation components
Also draw the in vitro cascade. Highlight the differences |
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Definition
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Term
Define..
a. zymogen
b. serine protease
Explain why it is important to know the type of proteolytic activity of these enzymes |
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Definition
a. zymogen: inactive form of an enzyme; coagulation factors exist as zymogens and require activation to catalyze the next reaction in the sequence.
b. serine protease: the active form of most coagulation factors exist as this type of enzyme, in which a serine at the active site breaks peptide bonds
Important to know the type of proteolytic activity to understand the background behind lab tests and diseases that relate to coag.
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Term
Describe and compare the general structure of...
1. fibrinogen
2. fibrin monomer
3. polymerized fibrin
4. stable fibrin
Explain how each is formed |
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Definition
1. Fibrinogen: trinodular structure composed of 3 pairs (Aα, Bβ, γ) of disulfide bonded polypeptide chains. Central nodule: E domain. Thrombin cleaves small peptides (A and B) from the alpha and beta chains in this region to form fibrin. The central nodule is joined by supercoiled alpha-helices to the terminal nodules also known as the D domains.
[image] |
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Term
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Definition
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Term
List the factors in the...
1. contact pathway
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Definition
1. contact
Starts with XII to XIIa; Prekallikrein & HMWK, XI to XIa; IX to IXa (w/ Calcium, VIII, PPL), PT (II) to Thrombin, Fibrinogen (I) to Fibrin monomer, to polymerized fibrin, which uses XIII to go to Cross-linked fibrin.
Factors...
XII/XIIa
XI/XIa
IX/IXa
VIII
II
I
XIII
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Term
| Correlate the old names for the contact and tissue factor pathways |
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Definition
Contact-->Intrinsic
Tissue Factor-->Extrinsic
to remember
in contact
extra tissue? |
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Term
| Predict the effects of a decrease or inhibition of procoagulants or inhibitors on clot formation |
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Definition
1. Decreased/Inhibited procoagulants or clotting factors
=Excessive bleeding
can be hereditary or acquired (drugs/disease)
2. Decreased/Inhibited inihibtors of clot formation
=Unneeded clotting occurs
Hereditary/acquired (drugs/disease)
Function of inhibitors/procoagulants typically due to drugs, not disease
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Term
| List the 5 generic components of the enzymatic coag complexes, their roles, and then name the specific components of the tenase and prothrombinase complexes |
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Definition
1. PPL (from cell membranes) surface on which the reaction occurs (Platelet membrane (Plt. Factor 3), Endothelial cells)
2. The active enzyme, eg. Factor IXa, Xa
3. A cofactor embedded in the PPL to stabilize the enzyme and increase its activity
4. Calcium, helps hold enzyme to PPL and Cofactor
5. Zymogen (enzyme's substrate) eg. for IXa=X; for Xa=Prothrombin (II)
Tenase converts X to Xa
Composed of Ca2+, IXa, VIII, PPL
Prothrombinase converts PT (Factor II) to Thrombin
Composed of Xa, Ca2+, V, and PPL
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Term
List factors in the
2. the tissue factor pathway
3. the common pathway |
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Definition
2. Tissue Factor
VII->VIIa
X->Xa (w/ V, Ca2+, PPL)
II (Prothrombin) -> Thrombin
I (Fibrinogen)->Fibrin monomer on down (FInal step uses XIII)
3. Common
Starts at II (PT) ---(Xa and V, Ca and PPL)--->Thrombin
Thrombin converts Fibrinogen (I) to fibrin monomer, on down (Final uses XIII)
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