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BIO 507 Test2
Hemostasis
79
Biology
Graduate
04/13/2012

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Term
Name 3 basic mechanisms +1 of hemostasis
Definition
1) Vascular spasm - damaged arterioles and arteries constrict

2) Platelet plug formation

3) Blood clotting (coagulation)

+1 is Fibrin thread formation
Term
Name 5 steps of clotting (pic on slide 2)
Definition
1. Severed vessel
2. Platelets agglutinate
3. Fibrin appears.
4. Fibrin clot forms
5. Clot retraction
Term
How long does clot retraction occur?
Definition
20-60 min
Term
When does fibrin clot form?
Definition
When fibrin and platelets cross link
Term
What is fragments of precursor megakaryocytic?
Definition
Platelets – thrombocytes
Term
What is thrombopoietin
Definition
a hormone produced by the liver and kidneys that regulates
megakaryocyte and platelet production
Term
Where are platelets formed? sequestered?
Definition
Formed in bone marrow, 150 - 350,000 /µl

Sequestered in spleen, 30%
Term
Plt diameter, life span in days, nucleus or no nucleus?
Definition
Plt 2-4 micrometer in diameter, life span 8-12 days, no nucleus
Term
Which factor crosslinks fibrin
Definition
fibrin stabilizing factor (factor XIII)
Term
3 things that make up contractile unit and let the plts change shape
Definition
Cytoplasm of plt has actin and myosin contractile proteins and thrombosthenin (an ATPase) - for clot retraction
Term
How does appearance differ from Activated plt and
Unactivated plt
Definition
Activated plt differ in shape (changes shape when releasing substances to other plts that haven’t been activated.

This activates them to inc number of plts, thus, helping with clotting
Term
When does plt plug formation occur?
Definition
When there is break or damage in basement membrane epithelium and capillary
Term
What is first step of plt plug formation
Definition
Platelet adhesion



Platelets stick to damaged area specifically COLLAGEN!! (in basal membrane)
Term
What is thromboxane a 2
Definition
Promotes vasoconstriction and plt aggregation
Term
What is 2nd step of plt plug formation?
Definition
Platelet release reaction (de-granulation)

Change shape

Spill contents of their granules: (active others!)

Alpha granules (PDGF)
Dense granules (variety of chemicals)
Term
What are Dense granules in plt plug formation
Definition
(containing
ADP or ATP,
calcium, and
serotonin)
Term
What are Alpha granules in plt plug formation?
Definition
(containing
platelet factor 4,
transforming growth factor-β1,
platelet-derived growth factor,
fibronectin,
B-thromboglobulin,
vWF,
fibrinogen, and
coagulation factors V and XIII)
Term
Platelet aggregation forms this.
Definition
forms a platelet plug
Term
What is released from damaged cells,

secreted into blood vessel?
Definition
Tissue factor starts the extrinsic pathway
Term
What is required for blood clotting
Definition
Ca++ is required to promote or accelerate all the blood clotting reactions.
Term
What converts prothrombin to thrombin ?
Definition
Prothrombinase (with Ca)
Term
What converts fibrinogen to fibrin
Definition
Ca and thrombin
Term
what is INSOLUBLE in extrinsic pathway
Definition
fibrin is INSOLUBLE!!
Term
What strengthens crosslinks b/t fibrin threads - to make clot stronger
Definition
Factor XIII-

Thrombin activates this
Term
Clot formation operates under what kind of mechanisms.
Definition
Clot formation operates under positive feedback mechanisms.
Term
What dissolves clot
Definition
plasmin

Plasminogen is converted to plasmin
Term
Prevents clots from spontaneously forming
along epithelium.
Definition
prostacyclin (considered anticoag)

Endothelial cells and WBCs also coated with prostacyclin.
Term
What triggers extrinsic and intrinsic system?
Definition
the extrinsic pathway, which is triggered by release of tissue factor from the site of injury,

and the intrinsic system, which is stimulated by contact with a negatively charged surface (like collagen).
Term
How many pro-coagulants & anticoagulants that have been identified within the blood.
Definition
There are >50 pro-coagulants & anticoagulants that have been identified within the blood.

The “anti” segment normally dominates until damage is sustained.
Term
Factor I
Definition
I - fibrinogen



(insoluble) fibrin is Ia
Term
Factor II
Definition
II - prothrombin


Thrombin is IIa
Term
Factor III
Definition
tissue factor
Term
Factor IV
Definition
Ca++
Term
Factor X
Definition
Stuart factor

activates prothrombin to thrombin-
Term
Fletcher factor
Definition
Prekallikren –
Term
High molecular weight kininogen
Definition
– Fitzgerald factor
Term
what factor is labile factor, pro-acclerin
Definition
Factor V -
Term
Factor VII –
Definition
stabile factor, serum prothrombin conversion accelerator
Term
Factor VIII –
Definition
antihemophilic factor (AHF, globulin or factor A)
Term
Factor IX –
Definition
AHF B, plasma thromboplastin component, Christmas factor
Term
What is XI –
Definition
Plasma thromboplastin antecedent
Term
What is XII –
Definition
Hageman factor
Term
Factor XIII –
Definition
Fibrin stabilization factor
Term
Which pathway is activated first? Extrinsic or intrinsic?
Definition
Both paths are activated simultaneously- its never one or the other!

Goal is to get to thrombin!
Term
Which pathway does the stuart factor get activate?
Definition
Factor X gets activated to Xa on both pathways.

This is critical player b/c it activates prothrombin to thrombin
Term
When does the common pathway begin?
Definition
After Xa

or

After stuart factor is activated
Term
What is the cell surface receptor for factor VIIa
Definition
Tissue factor –
Term
What allows the complex formation of TF with factor VII.
Definition
Exposure of TF expressing cells during injury
Term
this leads to the activation of factor VII on a membrane surface.
Definition
Factor VII and TF forming an equal molar complex (1:1 ratio) in the presence of calcium ions
Term
TF is expressed by
Definition
cells which are normally not exposed to flowing blood,

such as sub-endothelial cells (e.g. smooth muscle cells)

and

cells surrounding blood vessels (e.g. fibroblasts).

Endothelial cells do not express TF EXCEPT when they are exposed to inflammatory molecules

such as tumor necrosis factor-alpha (TNF-alpha).

Platelets & monocytes also express TF.
Term
What do plt phospholipids do?
Definition
- stimulate production of thrombin

are helpin to drive coagulation
Term
When blood is removed from a person, clotting can be prevented by?
Definition
by collecting blood with citrate ions

in light blue capped vacu-tainer (containing citrate) or
in purple tops (EDTA) or
green tops (heparin)
Term
What is the important difference between intrinsic and extrinsic pathway
Definition
the SPEED

EX pathway 15 secs

vs

IN pathway 1-6 mins


EX pathway is limited only by the amts of tissue factor & factors V, VII & X in the blood.
Term
Release of tissue factor occurs in which pathway
Definition
Tissue damage will result in release of tissue factor (extrinsic initiation)
Term
collagen contact with Factor XII & platelets occurs in which pathway
Definition
collagen contact with Factor XII & platelets (intrinsic initiation)
Term
What is present in blood plasma independently
Definition
Fibrinogen
Term
prevention of blood loss
Definition
The term hemostasis means
Term
capillaries
Definition
The megakaryocytes fragment into platelets, becoming smaller by squeezing thru
Term
glycoproteins
Definition
Outer coating of platelet cell membrane that repulses adherence to normal endothelium or causes adherence to injured vessels
Term
fibroblasts
Definition
once a blood clot is formed, it can become invaded by ______in order to form connective tissue thru the clot
Term
procoagulants & anticoagulants
Definition
whether blood will clot depends on the balance between these 2 substances
Term
Vit K
Definition
what is required by the liver to maintain normal activation of prothrombin?
Term
fibrinogen
Definition
Interstitial fluid does not normally clot; however increased permeability of the capillaries can allow _______to leak into the tissues to allow clotting
Term
SERUM
***serum CANNOT clot due to lack of clotting factors!!
Definition
Fluid is expressed from a formed clot w/in 60min, removing all fibrinogen & clotting factors. The fluid removed is called
Term
Platelets
***failure of clot retraction indicates low platelets in blood
Definition
These are necessary for clot retraction to occur
Term
Calcium ions
Definition
Blood clotting by either pathway does not occur in the absence of
Term
release of tissue factor
Definition
After a vessel is damaged, what is the 1st step in the extrinsic pathway
Term
EDTA
ethylenediaminetetraacetic acid
&
citrate
Definition
What substances chelates Ca? For example in the test tube
Term
Ca+ ions
Definition
What is needed in order for prothrombin to split & form thrombin?
Term
Intrinsic pathway
Definition
When platelets come in contact with collagen, they form a plug; however it is the soluble clotting factors making contact with collagen that initiates the
Term
Xa
***activated factor X
Definition
This activated factor is the actual protease that causes splitting of prothrombin to form thrombin
Term
Va
***activated factor V
Definition
This activated factor accelerates Xa protease activity, providing quick positive feedback
Term
thrombin IIa
Definition
This is the activated form of prothrombin
Term
fibrin Ia
Definition
This is the activated form of fibrinogen
Term
factor VII
***Intrinsic pathway
Definition
What factor along with Ca+ activates factor X within the intrinsic pathway?
Term
8.5-10.2 mg/dL
Definition
Normal serum Ca+ levels
Term
V
VII
X
Definition
The extrinsic pathway is limited by the amount of tissue factor & also by the amount of these factors (3)
Term
thrombin
Definition
The intrinsic converges with the extrinsic pathway @ the production of
Term
1. Sub-endothelial (smooth muscle)
2. fibroblasts
3. platelets
4. monocytes
Definition
These 4 types of cells express TF
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