Hemostasis and Thrombosis Quiz

Questions and Answers

What is the main difference between hemostasis and thrombosis?

Hemostasis occurs after death, while thrombosis occurs during life.

Hemostasis involves only platelets, while thrombosis involves the coagulation cascade.

Hemostasis occurs in the heart, while thrombosis occurs in vessels.

Hemostasis is a physiological process, while thrombosis is a pathological process.

What is the function of intact endothelial cells in maintaining liquid blood flow?

Inhibiting platelet adherence and preventing coagulation factor activation (correct)

Activating platelet adherence

Activating coagulation factor

Synthesizing pro-coagulant factors

What can induce endothelial dysfunction?

Hypotension

Hypertension and turbulent blood flow (correct)

Vitamin deficiency

Laminar blood flow

What is the role of platelets in endothelial repair?

Contributing to platelet-derived growth factor Signup and view all the answers

What are the three structural and molecular components involved in hemostasis and thrombosis?

Vascular wall, platelets, and coagulation cascade Signup and view all the answers

What is the result of dysfunctional endothelial cells?

They produce more pro-coagulant factors or synthesize less anticoagulant effectors Signup and view all the answers

What is a thrombus?

A mass formed from blood constituents within a vessel or the heart during life Signup and view all the answers

What is the consequence of thrombosis?

Serious consequences Signup and view all the answers

What is a common site for systemic venous thrombosis?

Brain Signup and view all the answers

What is the composition of a RED thrombus?

Red cells, platelets, and fibrin Signup and view all the answers

What is the direction of propagation of venous thrombi?

With blood flow Signup and view all the answers

What is the result of fibrinolytic mechanisms in thrombosis?

Dissolution of the clot Signup and view all the answers

What is the characteristic microscopic feature of a recent thrombus?

Lines of Zahn Signup and view all the answers

What is the effect of recanalization in thrombosis?

Providing capillary-sized channels for continuity of blood flow Signup and view all the answers

What is the characteristic feature of Disseminated Intravascular Coagulation (DIC)?

Sudden or insidious onset of widespread fibrin thrombi in the microcirculation Signup and view all the answers

What is the effect of Disseminated Intravascular Coagulation (DIC) on organs?

Diffuse circulatory insufficiency Signup and view all the answers

Which of the following is a key component of Virchow's Triad, contributing to thrombus formation?

Endothelial injury Signup and view all the answers

What is the primary effect of slowing blood flow in the context of thrombus formation?

Increased platelet adhesion to the vessel wall Signup and view all the answers

Which of the following is NOT a common cause of endothelial injury that can lead to thrombus formation?

Increased blood pressure Signup and view all the answers

Which of the following is a common factor contributing to hypercoagulability after surgery?

Increased levels of fibrinogen and prothrombin Signup and view all the answers

What is a common inherited abnormality that can lead to hypercoagulability?

Antithrombin III deficiency Signup and view all the answers

Which of the following factors is NOT typically associated with an increased risk of thrombus formation?

Regular exercise Signup and view all the answers

What is the primary component of a thrombus that forms in a rapid circulation?

Platelets Signup and view all the answers

Which of the following conditions is most likely to result in the formation of a thrombus in an artery?

Atherosclerosis Signup and view all the answers

What is the primary cause of a consumption coagulopathy in Disseminated Intravascular Coagulation (DIC)?

Consumption of platelets and coagulation proteins. Signup and view all the answers

Why is DIC considered a secondary complication rather than a primary disease?

It can be caused by a wide range of underlying conditions. Signup and view all the answers

Which of the following is NOT a typical cause of DIC?

Gastrointestinal bleeding. Signup and view all the answers

What is the primary treatment strategy for DIC?

Administration of fresh frozen plasma, platelets, and heparin. Signup and view all the answers

Which type of embolism is most commonly encountered (98% of cases)?

Thromboemboli. Signup and view all the answers

What is the primary cause of decompression sickness, also known as 'the bends'?

Formation of gas bubbles in the blood vessels due to rapid ascent. Signup and view all the answers

Which condition can potentially result in DIC as a complication?

Amniotic fluid emboli. Signup and view all the answers

Which type of embolism is associated with severe atherosclerosis?

Atheromatous emboli. Signup and view all the answers

What is the most common cause of pulmonary embolism?

Deep vein thrombosis in the legs Signup and view all the answers

What percentage of the pulmonary vasculature must be obstructed by a pulmonary thromboembolus to potentially cause sudden death?

60% Signup and view all the answers

Which of the following is NOT a common symptom or sign of pulmonary embolism?

Fever Signup and view all the answers

What is the difference between hypoxia and ischemia?

Hypoxia refers to a lack of oxygen in the tissues, while ischemia refers to a lack of blood flow to the tissues. Signup and view all the answers

What is the most common type of infarction?

Thromboembolic infarcts Signup and view all the answers

Which of the following organs is LEAST likely to be affected by an infarct?

Liver Signup and view all the answers

What is the underlying cause of anemic infarcts?

Blockage of an artery supplying the affected tissue Signup and view all the answers

Which of the following is NOT a common cause of arterial blockage leading to infarction?

Infection Signup and view all the answers

Study Notes

Thrombosis

Normal hemostasis prevents bleeding through a regulated process, maintaining blood in a fluid state and forming a clot when necessary.
Thrombosis represents pathological clot formation during life, occurring in intact blood vessels and may lead to serious complications.
Thrombosis involves three main components: the vascular wall, platelets, and the coagulation cascade.
Endothelial cells promote fluid blood flow by inhibiting platelet adhesion, preventing coagulation factor activation, and lysing any formed blood clots.
Dysfunctional endothelial cells can produce pro-coagulant factors or reduce anticoagulant effectors, contributing to thrombosis.
Various factors can induce endothelial dysfunction including hypertension, bacterial endotoxins, and toxins from cigarette smoke.

Platelet Function

Platelets maintain vascular endothelial integrity and contribute to vascular repair through PDGF (Platelet-derived Growth Factor).
They play a crucial role in forming platelet plugs and initiating the coagulation cascade.
Tissue factor at injury sites is a key initiator of coagulation.
Thrombin ultimately converts fibrinogen into insoluble fibrin, forming the hemostatic plug.

Factors Predisposing to Thrombus Formation (Virchow's Triad)

Alterations in blood flow can bring platelets into contact with the vessel wall.
Endothelial injury promotes platelet adhesion and aggregation, caused by conditions like atheroma or local compression.
Hypercoagulability refers to alterations in coagulation pathways that predispose to thrombosis, caused by factors such as increased platelets or inherited abnormalities.

Sites of Thrombosis

Arterial thrombi commonly arise from atheroma and consist mainly of platelets, often found in the brain and heart.
Venous thrombi develop in low-pressure environments in veins, especially in the deep veins of the calf, and can lead to pulmonary embolism.
Recent thrombi exhibit gross morphology as solid red to red-tan masses that can occlude blood vessels and microscopic features like Lines of Zahn, indicating layered structures.

Fate of Thrombi

Thrombi can propagate, embolize, dissolve via fibrinolytic mechanisms, or undergo organization and re-canalization, which may not fully restore blood supply.

Disseminated Intravascular Coagulation (DIC)

DIC involves widespread microthrombi formation and can lead to circulatory insufficiency and bleeding due to consumption of platelets and coagulation factors.
It is a complication arising from conditions like sepsis and trauma and often presents in ICU patients.
Treatment includes fresh frozen plasma to restore clotting factors and heparin to prevent further thrombus formation.

Embolism

Embolism is the obstruction of a blood vessel by a detached mass, often resulting from thromboemboli, which are the most common type.
Can also occur due to fat, gas, tumor, and bacterial emboli, each originating from different medical conditions and traumas.

Pulmonary Embolism

Most pulmonary emboli originate from deep leg vein thrombi and can lead to sudden death if they obstruct a significant portion of the pulmonary vasculature.
Symptoms include chest pain, dyspnea, tachypnea, cough (hemoptysis in 50% of cases), and hypoxia.

Infarction

Infarction causes localized tissue death due to inadequate blood supply, with hypoxia and ischemia as primary mechanisms.
Common sites include the heart, lungs, and brain, while the small intestine and kidneys are less common.
Nearly all infarctions arise from complete or near-complete occlusion of arterial blood flow, usually via thromboembolism.
Anemic infarcts are characterized by a lack of erythrocytes and typically occur in organs with singular arterial supply such as the spleen and kidney.

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Test your knowledge of hemostasis and thrombosis, including the roles of endothelial cells, platelets, and their functions in maintaining blood flow and preventing clotting.