Biology Chapter 12 Flashcards

Thrombosis and Pulmonary Embolism

• Thrombus: a blood clot that develops in an intact blood vessel.
• Embolus: a thrombus that detaches and travels through the bloodstream.
• Embolism: occurs when an embolus lodges in a smaller blood vessel, blocking blood flow.
• Virchow's Triad identifies three factors for thrombus formation: blood stasis, endothelial injury, and hypercoagulability.
• Two types of venous thrombosis: deep vein thrombosis (DVT) and pulmonary embolism (PE).
• Most thrombi are located in the legs, typically leading to venous complications.
• Types of thrombosis: venous and arterial.
• Predisposing factors for venous thrombosis include prolonged bed rest, varicose veins, increased blood coagulability, and ineffective venous pumping.
• Outcomes of venous thrombosis may include leg swelling or pulmonary embolism.

Effects of Pulmonary Embolism

• A large pulmonary embolism can block major pulmonary arteries, but may not cause lung infarction due to collateral circulation.
• A small pulmonary embolism may occlude peripheral arteries, leading to lung segment infarction and necrosis.
• Signs of a large PE include dyspnea, cyanosis, shock, and potential sudden death.
• Signs of a small PE include dyspnea, pleuritic chest pain, cough, and hemoptysis.
• Chest x-ray can detect lung infarcts but not identify the presence of an embolus.
• CT scans are effective in diagnosing PE via observation of obstructed blood flow.

Prevention and Risks

• Preventive measures for PE include ambulation, compression stockings, low-dose anticoagulants, and possibly IVC filters.
• Arterial thrombosis usually results from vessel wall injury due to arteriosclerosis, leading to plaque formation.
• Gangrene refers to tissue necrosis caused by inadequate blood supply.
• Intracardiac thrombi are blood clots formed within the heart, posing risks of distal embolization affecting organs like the spleen and brain.

Fluid Management and Edema

• Increased coagulability can lead to thrombosis due to factors like hormonal contraceptives, genetic mutations, and tumor-associated thromboplastic substances.
• Edema typically first manifests in the ankles and legs.
• Four key factors regulating capillary fluid flow: capillary hydrostatic pressure, permeability, osmotic pressure, and lymphatic channels.
• Lymphatic channels play a critical role in maintaining fluid balance by removing interstitial fluid.
• Capillary hydrostatic pressure pushes fluid from capillaries into extracellular spaces.
• Pitting edema leaves an imprint when pressure is applied.

Shock

• Pleural effusion indicates fluid accumulation in the pleural cavity surrounding the lungs.
• Ascites refers to fluid accumulation in the peritoneal cavity.
• Shock is a life-threatening condition resulting from failure in the circulatory system to adequately perfuse body tissues.
• Categories of shock: hypovolemic (low blood volume), cardiogenic (inadequate heart output), septic (infection-related), and anaphylactic (allergic reaction).
• Symptoms of shock include rapid shallow breathing, cold and clammy skin, weak rapid pulse, and low blood pressure.
• Treatment includes vasodilatory medications and intravenous fluids for volume restoration.

Test your knowledge with these flashcards on Chapter 12 of Biology. This chapter covers important concepts such as thrombus, embolus, and embolism, as well as Virchow's triad. Each card provides a definition to deepen your understanding of these terms.