Renal System The goal of these lectures is to discuss basic renal physiology. This lecture will present the regulation of H and Ca ions as well as discuss the hormonal and neural regulation of renal function. The sections for this lecture are: 17 of H and Ca ions homeostatic control, acidosis / alkalosis, homeostasis, sites and Calcium related metabolic bone diseases, Hormonal and neural control of renal function Life is a series of chemical reactions occurring in compartmentalized environments. The main purpose of life is to keep itself alive Physiology, the study of how life works, is based on the simultaneous occurrence of the following three concepts: levels of organization structure / function relationship homeostatic regulation levels of organization Renal System structure - function homeostatic regulation 1
Renal System what it actually is (info from feedback), is compared with what it should be (info from set-point) in a comparator / integrator Homeostasis, or constancy of the internal environment, is needed for chemical reactions underlying life to occur. It is maintained, predominantly, through negative feedback mechanisms error signal amplification S E effect effectors mechanism integrators compare what it should be with what it actually is and generate an error signal Renal System Homeostatic Control central integration center afferent efferent S receptor E effector negative feedback signal integrators compare what it should be with what it actually is and generate an error signal 2
Renal System systemic blood pressure extrinsic control ADH autoregulation ALD valves FF GFR 1 2 3 4 5 BLOOD BLOOD GLOM PCT HL JGA/MD DCT CD 1 reabsorption / secretion 2 concentration 3 sensors 4 solute rectifier 5 water rectifier URINE S receptor E Renal System Introduction, first lecture Nephron structure and functions Filtration, reabsorption and secretion Clearance (inulin, glucose, PAH, creatinin) Micturition, control of bladder input / output sphincters Basic renal regulation, previous lecture Balance of Na / H2O and countercurrent mechanism Renal Na / K regulation, aldosterone and the RA system Renal H2O regulation, baro / osmo receptors and AVP Diabetes (mellitus vs insipidus), diuretics, renal disease, previous lecture of hydrogen ions and calcium ions, this lecture diseases, Hormonal and neural control of renal function, this lecture 3
Renal System Sources of Hydrogen Ion Gain or Loss (chloride shift) diseases, (from the respiration lectures) 4
diseases, (from the respiration lectures) HC03 - HP04 2- NH 3 diseases, 5
diseases, 1, respiratory acidosis 2, respiratory alkalosis 3, metabolic acidosis 4, metabolic alkalosis HCO3 24 1 60 mmhg 40 mmhg PCO2 20 mmhg 4 diseases, 3 2 HCO3 ph = pk + log PCO2 7.2 7.4 7.6 ph 6
Change in Arterial level of H, HCO3 and CO2 1, respiratory acidosis 2, respiratory alkalosis 3, metabolic acidosis 4, metabolic alkalosis HCO3 24 1 60 mmhg 40 mmhg PCO2 20 mmhg 4 diseases, 3 2 HCO3 ph = pk + log PCO2 7.2 7.4 7.6 ph Renal Response to Acidosis and to Alkalosis diseases, 7
diseases, diseases, 8
diseases, diseases, PTH increases blood Ca and Calcitonin decreases it Vit. D calcitonin intestine calcitonin blood Ca kidney PTH calcitonin PTH bone 9
diseases, PTH increases blood Ca and Calcitonin decreases it blood Ca decrease PTHr Gs / AC Gq / PLC bone formation, osteoblast kidney, Ca filtration intestine, Ca secretion receptor parathyroid gland PTH Calcitonin r Gs / AC Calcitonin thyroid gland receptor bone resorption, osteoclast kidney, Ca reabsorption, Vit. D intestine, Ca absorption blood Ca increase Control of renal function systemic blood pressure extrinsic control ADH autoregulation ALD valves FF GFR 1 2 3 4 5 BLOOD Mechanism of action Renin is a protein Angiotensin is a peptide Aldosterone is a steroid ANP = ANF is a peptide Sympathetic ANS AVP = ADH is a peptide BLOOD GLOM PCT HL JGA/MD DCT CD 1 reabsorption / secretion 2 concentration 3 sensors 4 solute rectifier 5 water rectifier URINE 10
Control of renal function 11