Pathology Definitions

 Chapter 4: Hemodynamic disorder, Thromboembolism and Shock

Edema and effusion: Disorders that perturb cardiovascular, renal, or hepatic function are often marked by the accumulation of fluid in tissues (edema) or body cavities (effusions).

Hyperemia and Congestion: Hyperemia is an active process in which arteriolar dilation (e.g., at sites of inflam- mation or in skeletal muscle during exercise) leads to increased blood flow. Affected tissues turn red (erythema) because of increased delivery of oxygenated blood) Conges- tion is a passive process resulting from reduced venous outflow of blood from a tissue. It can be systemic, as in cardiac failure, or localized, as in isolated venous obstruction. Congested tissues have an abnormal blue-red color (cyanosis) that stems from the accumulation of deoxygenated hemo- globin in the affected area.

Hemostasis is a precisely orchestrated process involving platelets, clotting factors, and endothelium that occurs at the site of vascular injury and culminates in the formation of a blood clot, which serves to prevent or limit the extent of bleeding.

Hemorrhagic Disorders: Disorders associated with abnormal bleeding inevitably stem from primary or secondary defects in vessel walls, platelets, or coagulation factors, all of which must function properly to ensure hemostasis.