1 BLOOD COAGULATION Flashcards
What is Hemostasis?
Process of stopping blood loss, stops bleeding and keeps the blood inside the damaged vessel.
What is the opposite to hemorrhage?
Hemostasis
What is the first step in wound healing?
Hemostasis, it involves the change of blood form liquid into a gel
What is Blood coagulation?
Principle mechanism of hemostasis
What is a Blood Clot?
A mash of protein filaments that traps blood’s formed elements to form a red gelatinous mass
What does a blood clot consist of?
4 components. RBC, WBC, Platelets, and Cross linked Fibrin strands.
What are the 4 components of blood clot called (RBC, WBC, Platelet, and Fibrin strands)?
Clotting Factors
What are fibrin threads?
Threads that holds the blood cells together and they seal the wound to prevent blood loss
What are Platelets?
Circulate in blood and form a platelet plug over damaged vessels
Are platelets part of secondary or primary system?
PRIMARY
What are the primary functions of platelets?
1) Platelet adherence
2) Platelet aggregation
3) Providing support for coagulation cascade and healing
What is platelet adherence ?
Sticking to the injured vessel
What is platelet aggregation?
Attaching to other platelets to enlarge plug
Clotting factors are primary or secondary system?
Secondary
What are Clotting Factors?
Group of proteins that act with platelets in the clotting cascade
What are clotting factors produced by?
The liver
Are clotting factors present in the blood?
Yes, they are always present, but they are an inactive form
When do clotting factors become activated?
Activation upon injury through the extrinsic and intrinsic pathways
When clotting factors are active, what do they work to produce?
A fibrin clot
What is required to produce clotting factors?
Vitamin K
Source: Gut Flora, or from external sources
What is Clotting Factor I?
Fibrinogen
What is Clotting Factor II?
Prothrombin
What is Clotting Factor V?
Preaccelerin
What is Clotting Factor VII?
Proconvertin
What is Clotting Factor VIII?
Antihemophilic Factor
What is Clotting Factor IX?
Christmas Factor
What is Clotting Factor X?
Stuart Prower Factor
What is Clotting Factor XI?
Plasma Thromboplastin Antecedent
What is Clotting Factor XII?
Hageman Factor
What is Clotting Factor XIII?
Fibrin-Stabilizing Factor
What does Coagulation result from?
Fibrin (fibrinogen in tissue).
Is Fibrinogen normally active or inactive?
Normally inactive in the blood and gets activated by the presence of thrombi
What is the most important constituent of coagulation?
Thrombi
What activates prothrombin to Thrombin?
Clotting Factor X (stuart-power factor)
What are the 2 Factors of (Process of Blood Coagulation)?
1) Extrinsic Pathway (aka tissue factor pathway)
2) Intrinsic Pathway
Where is the damage that activates the Extrinsic Pathway?
Damage to cell BOTH within blood vessels and outside the vessels
What is the goal of the Extrinsic Pathway (aka tissue factor pathway)?
Cause a Thrombin Burst (fast release of thrombin)
Tissue Factor aka
Tissue Thromboplastin
What is Tissue Factor aka Tissue Thromboplastin released by?
Injured cells, both injured blood vessel cells and injured tissue cells, activates clotting factors
What is the Extrinsic Pathway steps?
1) Tissue Thromboplastin
2) Proconvertin (CF 7)
3) Stuart-Prower factor (CF 10)
4) Prothrombin
5) Thrombin
6) Fibrinogen
7) Fibrin
What is the Intrinsic Pathway?
Exposure of collagen fibers of sub endothelial cells of blood vessels to blood flow activates clotting factors
Where does the Intrinsic Pathway occur?
ONLY inside injured blood vessels
What are the steps of the Intrinsic Pathway?
1) Collagen Fibers Exposed
2) Hageman Factor (CF XII)
3) Plasma Thromboplastin Antecedent (CF XI)
4) Christmas Factor (CF IX)
5) Stuart-Prower Factor (CF X)
What ion plays an important role in Coagulation?
Calcium
What are patients with severe blood loss given to help coagulate blood?
Calcium Chloride injections
What is the main “Role of Platelets?”
Platelet activation and the Platelet Plug
Platelets aka
Thrombocytes
Where do the platelets occur?
ONLY inside injured blood vessels
What is the 3 step process to “Role of Platelets?”
1) Exposure of Collagen Fibers of sub endothelial cells of blood vessels to blood flow
2) Activation of Von Willebrand Factor
3) Platelets become activated
What happens during the Activation of Von Willebrand Factor (2nd step of Platelet process)?
It becomes activated when it attaches to the exposed collagen fibers, and this stops the movement of platelets. Platelets then form a single layer on top of the exposed collagen
What happens when Platelets become Activated (3rd step of Role of platelets)?
Platelets become activated and then a 2nd layer of platelets attach, then another, etc., and the platelet plug forms
Platelet activation results in the formation of _____
Platelet plug
What does the Platelet plug do?
Physically (mechanically) blocks the damaged blood vessel
What does Stasis result from?
Platelet activation (platelet plug) and coagulation (blood clotting via CF cascade) through 2 independent and simultaneous processes
Where can blood clots be formed?
Inside and Outside vessels
Where can Platelet plugs be formed?
Only inside a blood vessel
Platelets activated via Von Willebrand factor also undergo _____
DEGRANULATION
Activated Platelets release what 3 components?
1) ADP (adenosine diphosphate)
2) Thromboxane A2 (TxA2)
3) Growth Factors
What does ADP (adenosine diphosphate) promote?
Platelet activation
What is the main function of Thromboxane A2 (TxA2)?
Vasoconstriction to narrow the lumen to prevent blood loss
What do Growth Factors promote?
Wound Healing (enhances contracture) if there is injury by attracting fibroblast (chemotaxis)
What competes with the coagulation to keep safe limits?
Anticoagulation system
What prevents excess or uncontrolled blood clotting?
Anticoagulation system
What are the 3 major components of the Anticoagulation system?
1) Hemodynamics
2) Endothelial Mediation
3) Fibrinolytic System
What is Hemodynamics?
Slows blood flow. Important for coagulation otherwise activated CF’s get washed out and a clot cannot be formed
What is Endothelial Mediation?
As a result of injury, platelet plug is formed, surrounding uninjured endothelial cells release Prostacyclin (PGI2)
What does Prostacyclin (PGI2) do?
Prevents extra or excess platelet activation and aggregation
What does the Fibrinolytic System do?
Specific Fibrinolytic cascade:
What does CF 12 activate in the Fibrinolytic system?
Plasminogen activator, which converts plasminogen into plasmin
What does activation of plasminogen activator (plasminogen to plasmin) result in?
Degradation of activated CFs.
What does Plasmin do in the Fibrinolytic system?
Destroys the blood clot, exercise and physical activity strengthens this fibrinolytic system
What are the Anticoagulation System steps?
1) CF XII
2) Plasminogen
3) Plasmin
4) Destruction of blood clot
What is Petechiae?
Pinpoint hemorrhages
What disease is associated with Petechiae (Petechial Rash)?
Scurvy
What is Purpura?
When hemorrhage is larger than a pinpoint, but < 2
What is Purpura?
When hemorrhage is larger than a pinpoint, but < 2 cm
What disease is associated with Purpura?
Systemic Autoimmune disease, Example: Lupus
What is the aka of bruises?
Ecchymoses, if hemorrhages are > 2 cm
What 3 diseases are associated with Ecchymoses aka bruises?
- Raccoon sign
- Battle sign
- Cushing’s Syndrome
What is Cushing’s Syndrome due to?
Overproduction of corticosteroids (cortisol) from adrenal cortex, causes overproduction of cortisol and aldosterone.
Cushing’s Syndrome has what 2 signs?
Constant stress (fight or flight state) and High BP from the aldosterone
What happens to the skin during Cushing’s Syndrome?
Atrophy of the skin (acne) and increases brittleness of blood vessels = not being able to do wound healing (easy subcutaneous bruising)
What happens to the bones during Cushing’s Syndrome?
Severe Osteoporosis. Activates osteoclasts (proteolysis of bone matrix)
How does the sugar metabolism present in Cushing’s Syndrome?
Hyperglycemia (gluconeogenesis, decreases glucose use). As a response, body secretes insulin, there’s too much cortisol which = Insulin resistance
ADRENAL DIABETES
Obesity is associated with what disease?
Cushing’s syndrome
What can have symptoms similar to Cushing’s Syndrome?
Prolonged steroid medication (easy bruising).
What is Hematoma?
Leak of blood into cavities or into (or a muscle belly)
What happens during a Hematoma?
Rupture of middle meningeal artery will cause –> epidural hematoma (epidural space = abnormal)
What are the 4 Hemorrhagic Disorders?
1) Thrombocytopenia
2) Von Willebrand’s Disease
3) Hemophilia
4) Hemoarthrosis
What is Thrombocytopenia?
Decreased number of platelets
What is the normal platelet count in blood?
250,000 - 300,000 mm3
What is the platelet count in Thrombocytopenia?
100,000 or less, no proper coagulation -> prone to hemorrhage
What rashes are seen in Thrombocytopenia?
Petechial or Purpural (both less than 2cm)
Where are thrombocytopenia diseases seen?
Immunological diseases and Leukemia
Is Von Willebrand’s Disease genetic?
YES, Patient has sick parents
What is the problem in Von Willebrand’s Disease?
Patient does not produce Von Willebrand Factor
What does no production of Von Willebrand factor lead to?
Leads to NO platelet activation, no platelet plug, and no coagulation
What can happen during Von Willebrand disease?
Periodic Leakage of blood from mucosa of the stomach and duodenum (common)
Hemorrhagic Gastroduodenitis = BLACK STOOL (Malena)
Menorrhagia is associated with what disease?
Von Willebrand’s Disease
What is Menorrhagia?
Increased amount of blood lost during menstruation - heavy and prolonged menses related to abnormal coagulation
What is Metrorrhagia?
Similar to menorrhagia but NOT related to Von Willebrand’s disease. Usually from Uterus Cancer
What does Metrorrhagia result in?
Loss of blood BETWEEN menstrual periods
What is Hemophilia?
Non Production of certain clotting factors
Can Hemophilia be Genetic?
YES, children with this disease have parents that DO NOT have the disease
Who is the carrier of Hemophilia?
A woman, but women very rarely have this disease, they pass it onto their sons (pt does not have sick parents)
What is Hemophilia linked?
X - Linked
What is the main problem in Hemophilia?
Lack of certain clotting factors, no convergence of fibrinogen to fibrin, no BLOOD CLOT
What are the 2 major types of Hemophilia?
Hemophilia A and B
What is happening in Hemophilia A?
Non production of CF 8 VIII (Antihemophilic Factor)
What is Hemophilia B aka
Christmas disease
What is happening during Hemophilia B?
Non production of CF 9 IX (Christmas factor) = Affects the intrinsic coagulation pathway
What is Hemoarthrosis caused by?
A problem caused by small traumas that may lead to severe blood loss
What disease is Scurvy related to?
Hemoarthrosis
What does Trauma in Hemoarthosis lead to?
Blood in Joint spaces (knee joint)
What must happen during Hemoarthrosis for it to get better?
Blood removed from joint space to prevent degeneration
What happens in Hemoarthrosis?
Iron is released from heme groups into blood, destroys the joint cartilage, degeneration (NON inflammatory) of the joint aka OSTEOARTHROSIS
(Secondary OA)
Is Hemarthrosis related to Ankylosis?
NO, ankylosis is an inflammatory joint disease OA is degenerative
