CHAPTER 4: HEMODYNAMIC DISORDERS, THROMBOEMBOLISM, AND SHOCK

• The health of cells and tissues depends on the circulation of blood, which delivers oxygen and nutrients and removes wastes generated by cellular metabolism
• Under normal conditions, proteins in the plasma are retained within the vasculature as blood passes through capillary beds
• Disturbances in this balance can lead to edema, which is the accumulation of fluid in tissues resulting from a net movement of water into extravascular spaces
• Edema can have minimal or profound effects depending on its severity and location
• Structural integrity of blood vessels can be compromised by trauma
• Hemostasis is the process of blood clotting that prevents excessive bleeding after blood-vessel damage
• Inadequate hemostasis may result in hemorrhage, compromising regional tissue perfusion and potentially leading to hypotension, shock, and death
• Thromboembolism can obstruct blood vessels, potentially causing ischemic cell death (infarction)
• Thromboembolism is a major cause of morbidity and death in developed countries, including myocardial infarction, pulmonary embolism (PE), and cerebrovascular accident (stroke)
• Hyperemia is an active process resulting from arteriolar dilation and increased blood inflow, often seen at sites of inflammation or in exercising skeletal muscle
• Congestion is a passive process resulting from impaired outflow of venous blood from a tissue, leading to an abnormal blue-red color (cyanosis) in congested tissues
• Chronic congestion can lead to inadequate tissue perfusion, persistent hypoxia, parenchymal cell death, secondary tissue fibrosis, edema, and sometimes rupture of capillaries producing focal hemorrhages
• On microscopic examination, acute pulmonary congestion is marked by blood-engorged alveolar capillaries, alveolar septal edema, and intraalveolar hemorrhage
• In chronic pulmonary congestion, the septa become thickened and fibrotic, alveolar spaces contain macrophages laden with hemosiderin ("heart failure cells") derived from phagocytosed red cells
• Factors influencing infarct development include thromboembolism, which can obstruct blood vessels and cause ischemic cell death
• Shock can be caused by various factors and has stages including the pathogenesis of septic shock
• Stages of shock include hypoperfusion, compensatory, progressive, and refractory stages
• Active process resulting from arteriolar dilation and increase blood flow.

  Hyperemia
• passive process resulting from paired outflow of venous blood from a tissue.

  Congestion
• These tissues are redder than normal due to oxygentaed blood

  Hyperemic tissues
• Tissues have an abnormal blur-red color (cyanosis)

  Congested tissues
• Accumulation of interstitial fluid within tissues

  Edema
• Most common cause of albumin loss from blood

  Nephrotic syndrome
• It is a protein rich inflammatory fluid with a specific gravity of 1.020

  Exudate
• It is a protein poor inflammatory fluid with a specific gravity of 1.012


  Transudate
• Extravasation if blood from vessels due ti damaged blood vessels or defective clot formation.

  Hemorrhage
• A type of hemorrhage in which there is rupture of blood vessels like bruising

  Hematoma
• Hemorrhage in which low platelet count, defective platelet function, and deficiency in vitamin C is evident.

  Petechiae
• Hemorrhage in which vascular inflammation or vasculitis and increase vascular fragility is evident.

  Purpura
• Are subcutaneous hematomas

  Ecchymoses
• Prothrombin time records the time for a fibrin clot to form, what factors are involved in this?

  Extrinsic factors VII, X, V, II, and finbrinogen.
• This assay involved the recording of the time to fibrin clot formation which involved intrinsic pathways XII, XI, IX, VIII, X,V, II and fibrinogen.

  Partial thromboplastin time
• Virchow triad

  • Endothelial injury
  • Stasis or turbulent blood flow
  • Hypocoagubility
• Detached intravascular solid, liquid, or gaseous mass that is carried by the blood from its point of origin to a distant site.

  Embolism
• An area if ischemic necrosis caused by occlusion of the vascular supply to the affected tissue

  Infarction
• Diminished cardiac output or reduced effective circulating blood volume impairs tissue perfusion and leads to cellular hypoxia

  Shock
• A type of shock that entails a low cardiac input due to myocardial pump failure

  Cariogenic shock
• A type of shock that entails a low cardiac output due to loss of blood plasma or plasma volume

  Hypovolemic shock
• A type of shock triggered with microbial infections and it is associated with severe systemic inflammatory syndrome is known as a septic shock.
• Anaphylactic shock is a severe allergic reaction that can be fatal, it results from systemic vasodilation and increased vascular permeability that is triggered by IgE mediated hypersensitivity.