Define hydrostatic pressure and colloidal oncotic pressure. How does each contribute to the formation of edema?
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Hydrostatic pressure is the force exerted by fluid against the walls of capillaries, pushing fluid out. Colloidal oncotic pressure is the pull exerted by proteins (mainly albumin) to retain fluid in the capillaries. Increased hydrostatic pressure or decreased oncotic pressure can lead to edema by allowing fluid to accumulate in tissues.
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Define hydrostatic pressure and colloidal oncotic pressure. How does each contribute to the formation of edema?
Hydrostatic pressure is the force exerted by fluid against the walls of capillaries, pushing fluid out. Colloidal oncotic pressure is the pull exerted by proteins (mainly albumin) to retain fluid in the capillaries. Increased hydrostatic pressure or decreased oncotic pressure can lead to edema by allowing fluid to accumulate in tissues.
Diagram Virchow’s Triad and list a disease process that disrupts each component.
Endothelial injury (e.g., trauma or atherosclerosis), Hypercoagulability (e.g., inherited clotting disorders, cancer), Stasis of blood flow (e.g., immobility or varicose veins).
Contrast a white infarct from a chronic infarct with fibrosis present.
White infarct: Recent, with fresh necrotic tissue and lack of blood flow. Chronic infarct with fibrosis: Occurs after healing, where fibrous tissue replaces the necrotic tissue, leaving a scar.
Compare petechiae, ecchymoses, and hematoma formation. What are the clinical implications (causes) for each?
Petechiae: Small, pinpoint hemorrhages, often due to platelet disorders or capillary fragility. Ecchymoses: Larger bruises caused by trauma or coagulation disorders. Hematoma: A collection of blood outside blood vessels, often due to significant trauma or vessel rupture.
Diagram the role of von Willebrand’s Factor (vWF) in hemostasis. How might a dog with vWF deficiency (Von Willebrand’s Disease) present?
vWF helps platelets adhere to the damaged vessel and stabilizes Factor VIII in the clotting process. A dog with vWF deficiency may present with bleeding disorders like prolonged bleeding after injury or surgery, nosebleeds, or excessive bruising.
Contrast fibrin and fibrosis. Which implies acute inflammation?
Fibrin: A protein involved in blood clotting, often associated with acute inflammation. Fibrosis: The formation of excess fibrous tissue, usually a response to chronic inflammation and healing.
Define ascites, pitting edema, hydrothorax, and hemoabdomen.
Ascites: Accumulation of fluid in the abdominal cavity. Pitting Edema: A form of swelling where pressing leaves a visible dent. Hydrothorax: Fluid accumulation in the pleural cavity. Hemoabdomen: Blood in the abdominal cavity.
Contrast white and red infarcts. Diagram an infarct in a kidney, including where the vessel occlusion occurred and the extent of tissue death.
White infarcts: Occur in solid organs (e.g., heart, kidneys) due to arterial occlusion, leading to coagulative necrosis. Red infarcts: Occur in tissues with dual blood supply or venous occlusion, such as the lungs or intestines. Kidney infarct diagram: Vessel occlusion occurs in a renal artery, leading to wedge-shaped necrosis of tissue downstream from the blockage.
Contrast primary and secondary hemostatic plugs. What is the major event that occurs in each?
Primary hemostatic plug: Platelets form a temporary plug by adhering to exposed collagen and aggregating at the site of injury. Secondary hemostatic plug: Fibrin is laid down to stabilize the platelet plug, forming a more durable clot.
Describe how thrombi are resolved.
Thrombi can be resolved through dissolution by fibrinolysis, recanalization (formation of new channels within the clot), or organization into fibrous tissue as part of healing.
