Class 10 Flashcards
What is thrombosis
Thrombosis
Clotting of WBC’s into aggregate of blood cells and fibrin
What is fibrin
Thrombosis
Polymerized fibrinogen
What is a thrombus?
Thrombosis
Network of filaments binding blood cells to form plug (thrombus)
What promotes thrombosus?
Pathogenesis
Clotting factors and Platelets
What counteracts thrombosus
Pathogenesis
Endothelial cells and plasmin
Intravascular coagulation is the result of which three things?
Pathogenesis
- Coagulation proteins
- Endothelial cells
- Platelets
What is the main coagulation protein and how does it work?
1) Coagulation proteins
Thrombin
Converts fibrinogen into fibrin
What is the role of endothelial cells in coagulation?
2) Endothelial Cells
Can initiate thrombosis by through activation by cytokines (inflammation)
Normal resting endothelial cells have what kind of function in regards to coagulation?
2) Endothelial cells
Have antithrombotic function
What is the role of platelets in coagulation?
3) Platelets
Neutralize anticoagulation factors and secrete thromboxane
What does Virchow’s triad entail?
Pathogenesis of Thrombi
Virchow’s Triad:
1. Endothelial Cell injury
2. Hemodynamic changes
3. Hypercoagulability of whole blood
How can Endothelial cell injury cause pathologic thrombus formation?
Pathogenesis of Thrombi
Inflammatory mediators cause endothelium to lose antithrombotic properties
How can hemodynamic changes cause pathologic thrombus formation?
Pathogenesis of thrombi
Slow blood floow results in sedimentation and small thrombi not dissolving
What is the role of hypercoaguability in pathologic thrombus formation?
Pathogenesis of thrombi
fluid loss cause thicker blood/higher chance for clotting
How are Thrombi classified?
Classification
Based on location or gross appearance
Intramural thrombi
Classification
Endocardium - wall of heart chambers
Valvular Thrombi mimics what?
Classification
Mimics endocarditis (bacterial infection of valve)
Arterial thrombi
Classification
In arteries
Could be atherosclerosis or aneurisms.
Venous Thrombi are common in?
Classification
Common in varicose veins
could lead to thrombophlebitis.
Microvascular Thrombi
Classification
In arterioles, capillaries, venules
Red (conglutination) thrombi
Classification
Red thrombi in small vessels
Layered (sedimentation) thrombi
Classification
Layered appearance from Lines of Zahn
(Cellular elements and fibrin)
Occlusive thrombi can be?
Fate of Thrombi
Recanalized
Thrombi that break become what?
Fate of Thrombi
Emboli
Emboli can block blood vessel, potentially leading to what?
Fate of Thrombi
Infarction
What causes ischemia
Clinical Correlations
Occlusion of lumen of b.v.
What is the most common cause of myocardial infarction?
Clinical Correlation
Thrombotic occlusion of coronary arteries
What causes chronic heart failure?
Clinical Correlations
Slow narrowing lumen - Decreased blood flow - hypoxia, reduced function
What is it called when a thrombus detaches and becomes free-flowing in blood?
Clinical Correlations
Embolus
What is an infarct caused by?
Clinical Correlations
Most caused by thrombi or thromboemboli
What is a major cause of stroke?
Clinical Correlations
Cerebral infarct
What is an infected thrombus that breaks off called?
Clinical Correlations
Septic emboli
How are emboli classified
Classification (emboli)
What they are made of
What is a Thromboemboli
Classification of emboli
Thrombi carried by venous or arterial blood
What is liquid emboli
Classification of emboli
Fat emboli following bone fracture
What is a gaseous emboli
Classification of emboli
Gas bubble emboli, air injected in veins
What is solid particle emboli made of?
Classification of emboli
cholesterol, tumor cells, bone marrow
All emboli can occlude blood vessels, causing what?
Clincal Correlations
Ishcemia - reduced blood supply to organs
What is the most clinically significant emboli type, while all others are rare?
Clinical Correlations
Thromboemboli
What usually happens due to a venous emboli?
Clinical Correlations
Typically lodge in pulmonary artery causing pulmonary embolism
What do arterial emboli commonly cause?
Clinical Correlations
Ischemia in spleen, kidneys, intestines
Where do arterial emboli typically lodge?
Clinical Correlation
medium-sized arteries
Middle cerebral artery
What are Renal infarcts associated with?
Clinical Correlations
Hematuria
What can Intestinal infarcts cause?
Clinical Correlations
Gangrene of intestines
What is an infarction
Infarction
Sudden insuffiency of blood to an area causing necrosis
What are the two origins and two colors of infarctions
Arterial - white
Venous - red
What is a white/pale infarct?
Classification of Infarctions
Blockage in artery reducing blood supply to organs
Cause white tissues
What is a red infarction?
Classification of infarctions
Venous blockage causing pooled blood and red appearance
The fate of infarcts depends on what 3 factors?
Fate of Infarcts
Anatomic Site
Circulatory status
Capacity for repair
Can ischemic necrosis of post-mitotic cells (e.g. heart) be repaired
Fate of infarcts
No - only replaced by scar tissue
Can necrotic brain cells be repaired?
Fate of infarcts
No - liquefactive necrotic tissue reabsorbed leaving clear cyst
Can mitotic tissue and facultative mitotic tissue (e.g. liver) be repaired
Fate of infarcts
Yes with relatively few defects
Large infarcts can be impossible to regenerate completely, resulting in what?
Fate of infarcts
Scarring
Loss of function