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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
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