Metals: Role in Physiology and Pathology PDF

Metals: Role in physiology and pathology Dr K. Mehta https://ars.els-cdn.com/content/image/1-s2.0-S0022283619300270-ga1_lrg.jpg Created by Dr Kosha J. Mehta 19460911 Copyright @King...

Metals: Role in physiology and pathology Dr K. Mehta https://ars.els-cdn.com/content/image/1-s2.0-S0022283619300270-ga1_lrg.jpg Created by Dr Kosha J. Mehta 19460911 Copyright @King’s College London University Learning objectives 1. List the physiological functions of sodium, potassium, magnesium and calcium 2. Describe the diseases associated with these metals 3. State the functions of the transition metals iron, copper and zinc in human physiology 4. Present an overview of the diseases associated with iron, copper and zinc deficiencies and excess Sodium Mostly found in blood and in ECF (extracellular fluid) Mostly excreted in urine Physiological functions: Essential nutrient Helps in: maintaining normal cellular homeostasis Regulating fluid and electrolyte balance and blood pressure. Main regulator of ECF volume (through its osmotic action) including plasma volume transporting nutrients and substrates through plasma membranes Important for the excitability of muscle and nerve cells https://www.nature.com/articles/nrneph.2010.38  Sodium-associated diseases Too low Na in serum = Hyponatremia (serum Na total body sodium (body solutes) Water leaves the blood and enters cells, cells swell. Too high Na in serum= Hypernatremia (Serum Na >145 mmol/L ) Cause: limited access to water or impaired thirst mechanism Decrease in total body water relative to electrolytes “Water problem,” not a problem of Na homeostasis Water leaves cells and enters blood (aiming to dilute it and lower Na levels) https://www.actiononsalt.org.uk/ salthealth/factsheets/osteoporosis/ Too much Na in diet= facial puffiness, high blood pressure, heart disease and stroke It can also cause Ca loss (increases Ca excretion), some of which can be from bone  Potassium Mostly inside the cells than outside; present in all body tissues Mostly excreted in urine, 10% in sweat and stool K has a strong relationship with Na Physiological functions: Essential for normal cell function Maintains intracellular fluid volume and transmembrane electrochemical gradients Helps preserve acid-base balance and maintain isotonicity and electrodynamic cellular function Activates many enzymes e.g., pyruvate kinase Essential for transmission of nerve impulses, contraction of cardiac muscles, skeletal and smooth muscles, tissue synthesis, gastric secretion, and renal function Relaxes walls of blood vessels, lowers blood pressure https://www.pearson.com/content/dam/one-dot-com/one-dot-com/us/en/higher-ed/en/products-services/ course-products/marieb-10e-info/pdf/marieb-0321927028-chapter9.pdf Diseases associated with potassium Low levels of K in blood= Hypokalemia (< around 3 mmol/L) Cause 1: excessive K loss in urine (due to medications that increase urination) These medications are often prescribed for high blood pressure or heart disease Cause 2: Low K intake; associated with increased blood pressure and higher risk of stroke “If you have low K levels, you may have a heart problem, such as an irregular heartbeat” High levels of K in blood= Hyperkalemia (> 6.0 mmol/L) Can be life-threatening Heart muscle activity may be reduced, weakness, paralysis in feet or respiratory muscles Magnesium ATP 50% of body’s magnesium is in bone Very little in blood Physiological functions Cofactor in various structures/enzymes that regulate reactions Protein synthesis, muscle and nerve function, blood pressure regulation Required for energy production, oxidative phosphorylation, and glycolysis, and DNA, RNA and glutathione Regulates insulin secretion in pancreatic beta cells Critical for phosphorylation of insulin receptor Contributes to formation (structural development) of bone and teeth  Diseases associated with magnesium Too low = Hypomagnesemia (