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Category Archives: Physiology and Pathophysiology

Regulation of Hemostasis

23-Jul-17

Key events that initiate and propagate coagulation are the redistribution of negatively charged phospholipids to the cell surface and the exposure of tissue factor to the blood. The appropriate negatively charged phospholipids, primarily phosphatidylserine, can arise as a result of either cellular activation with strong agonists like thrombin together with collagen in the case of […]

Renal Handling of Urea

22-Jul-17

Renal Handling of Urate Urate, an anion that is the base form of uric acid, provides a fascinating example of the renal handling of organic anions that is particularly important for clinical medicine and is illustrative of renal pathology. An increase in the plasma concentration of urate can cause gout and is thought to be […]

Ammonia and Urea Cycle

20-Jul-17

Ammonia (NH3) is a small metabolite that results predominantly from protein and amino acid degradation. It is highly membrane-permeant and readily crosses epithelial barriers in its nonionized form. Ammonia does not have a physiologic function. However, it is important clinically because it is highly toxic to the nervous system. Because ammonia is being formed constantly […]

Overview of the Hemostasis System

15-Mar-17

Procoagulant Pathways Two procoagulant pathway have been identified which converge at the “intrinsic” (accessory) fXase (fIXa*fVIIIa) complex. The contact or “intrinsic” pathway is activated by the interaction of blood with a foreign surface. This pathway is activated by the factor XIIa-high-molecular-weight kininogen (HMWK)-prekallikrein complex in association with foreign surfaces including glass, dextran sulfate, or kaolin. […]

[Physiology][Hematology] General Concepts in Hemolytic Anemias

18-Nov-16

Hemolysis is the accelerated destruction of red blood cells (RBCs), leading to decreased RBC survival. The bone marrow's response to hemolysis is increased erythropoiesis, reflected by reticulocytosis. If the rate of hemolysis is modest and the bone marrow is able to completely compensate for the decreased RBC life span, the hemoglobin concentration may be normal; […]