【正文】 insulin overdose Barium poisoning Betareceptor excitomotory hypokalemic periodic paralysis 3. alterations of metabolism and function Nerve cells skeletal muscles gastrointestinal smooth muscle Myocardial cells Effects on body (1). nerves and muscles acute hypokalemia excitability 0 mv serum[K+] 30mv AP 60mv TP(Et) 90mv RP(Em) hyperpolarization (2). Heart arrhythmia 0 mv serum[K+] 30mv 60mv 90mv depolarization Excitability: [K+]ECF K+ permeability depolarization repolarization excitability ECG T wave Conductivity: RP 0 phase of AP conductivity conductive block unidirectional block ECG PR Autorhythmicity: Contractility: acute 。Disorders of Potassium Metabolism Outline I. Normal potassium metabolism and regulation II. Hypokalemia III. Hyperlalemia IV. Case discussion 1. the total potassium of body : intracellular: 98％（ 140160mmol/L） extracellular： 2％（ ） I. Normal potassium metabolism presents in the food, such as milk, peanut potatoes, salt substitute. Potassium excrete pathway: kidney through urine: 90％ ? Stool (feces): 10％ ? Sweat normal serum potassium: balance between intra and extracellular K+ normal: 15 h of potassium homeostasis ? Transcellular transfer ? Renal regulation (1) Potassium transcellular transfer Pumpleak mechanism factors: ? Potassium concentration in ECF ? Acidbase balance ? Insulin ? Catecholamine ? Osmolarity ? Exercise ? Total body potassium (2). Renal regulation for potassium excretion ? Glomerular filtration ? Reabsorption by the proximal tubule and the loop of Henle ? Regulation of potassium excretion in the distal and collecting tubules Sodiumpotassium ATP ase Permeability of luminal membrane for potassium Reabsorption in collecting tubules ? Hydrogenpotassium ATP aseproton pump Mechanism of potassium excretion in distal and collecting tubules: Influencing factors of potassium excretion in distal and collecting tubules: Potassium concentration in ECF Aldosterone Distal flow rate Acidbase balance (3) Potassium excretion in colon The same as the excretion in kidney function of potassium maintain cellular metabolism maintain cellular resting membrane potential regulate the osmolarity and acidbase balance Disorder of potassium metabolism Normal serum potassium: Hypokalemia Hyperkalemia facter of potassium homeostasis acidosis alkalosis hypoxia serum insulin serum damage of cells [K+] ADS [K+] catabolism anabolism distal flow rate distal flow rate 1. Definition : Hypokalemia is defined as a decrease in seru