N5315 Advanced Pathophysiology Renal and Urologic System Core Knowledge Objectives with Advanced Organizers

Anatomy and physiology of the Renal System 1. Discuss the physiologic relationship between phosphorus and calcium. 2. Discuss how calcium and phosphorus homeostasis is altered by renal disease and the pathologic consequences. 3. Examine the basic anatomy and physiology of the kidney. o Functions of the kidneys  the maintenance of water balance  the regulation of acid base balance  blood pressure regulation  secretion of erythropoietin which stimulates the growth of red blood cells. Disorders which affect the kidney may result in a decrease in the production of erythropoietin resulting in anemia.  activates vitamin D. The active form assists with the absorption of calcium in the intestines. The precursor to vitamin D is ingested in the food that we eat (vegetables and meat). After it is absorbed it is taken to the skin where UV light turns it into another precursor of vitamin D. This precursor then is transported to the kidney where it is converted into the active form of vitamin D, calcitriol. Calcitriol is then responsible for assisting with the absorption of calcium in the intestines, promoting the release of calcium from the bone (resorption), and decreasing renal calcium excretion. Disorders which affect the kidney can result in a vitamin D deficiency and hypocalcemia.  Glucose regulation. The kidneys help to maintain glucose balance by completing gluconeogenesis from amino acids, by taking up glucose from the circulation and by reabsorbing glucose from the glomerular filtrate. Renal gluconeogenesis is responsible for about 40% of the glucose formed by this process. The kidneys normally filter about 180 grams of glucose daily by the glomeruli, but all of this is absorbed in the proximal tubule by the sodium-glucose cotransporter 2 (SGLT2) protein. This helps to ensure adequate glucose is available during periods of fasting. When serum glucose levels exceed a threshold of 180 (some sources say 200) the SGLT2 transporters become saturated and the excess glucose spills over into the urine. This mechanism is