1. What is the difference between primary and secondary hemostasis? How are they regulated by the coagulation cascade? - Primary hemostasis is the formation of a platelet plug at the site of vascular injury, while secondary hemostasis is the stabilization of the plug by fibrin strands. They are regulated by the coagulation cascade, which consists of two pathways: the intrinsic and the extrinsic. The intrinsic pathway is activated by contact with damaged endothelium or collagen, while the extrinsic pathway is activated by tissue factor released from injured cells. Both pathways converge at the activation of factor X, which converts prothrombin to thrombin. Thrombin then converts fibrinogen to fibrin, which forms a mesh around the platelet plug. 2. What are the main types of shock and their pathophysiological mechanisms? - The main types of shock are hypovolemic, cardiogenic, obstructive, and distributive. Hypovolemic shock occurs when there is a loss of blood or fluid volume, leading to decreased venous return, cardiac output, and tissue perfusion. Cardiogenic shock occurs when there is a failure of the heart to pump effectively, leading to reduced cardiac output and tissue perfusion. Obstructive shock occurs when there is an obstruction of blood flow in the circulatory system, such as a pulmonary embolism, cardiac tamponade, or tension pneumothorax, leading to reduced cardiac output and tissue perfusion. Distributive shock occurs when there is a widespread vasodilation and increased capillary permeability, leading to reduced vascular resistance, blood pressure, and tissue perfusion. Examples of distributive shock are septic shock, anaphylactic shock, and neurogenic shock. 3. What are the main causes and consequences of acute respiratory distress syndrome (ARDS)? - The main causes of ARDS are direct or indirect lung injury that triggers an inflammatory response in the alveoli. Direct lung injury can be caused by pneumonia, aspiration, inhalation injury, or chest trauma. Indirect lung injury can be caused by sepsis, pancreatitis, transfusion reaction, or drug overdose. The consequences of ARDS are impaired gas exchange, hypoxemia, hypercapnia, respiratory acidosis, pulmonary edema, decreased lung compliance, increased airway resistance, and respiratory failure. 4. What are the main types of diabetes mellitus and their pathophysiological mechanisms? - The main types of diabetes mellitus are type 1, type 2, and gestational diabetes. Type 1 diabetes mellitus is caused by autoimmune destruction of pancreatic beta cells that produce insulin, leading to absolute insulin deficiency and hyperglycemia. Type 2 diabetes mellitus is caused by insulin resistance and relative insulin deficiency, leading to impaired glucose uptake and hyperglycemia. Gestational diabetes mellitus is caused by hormonal changes during pregnancy that increase insulin resistance and glucose production, leading to hyperglycemia