Medical Chemistry Lecture 2 Part 2: Elements in Human Body PDF

Medical Chemistry Lecture 2 part 2 The Chemical Basis of Life Elements in Human Body Learning Objectives ▪ Elements in the Human Body Sodium and its Role in the Human Body Potassium and its Role in the Human Body Calcium and its Role in the Human Body Iron and its...

Medical Chemistry Lecture 2 part 2 The Chemical Basis of Life Elements in Human Body Learning Objectives ▪ Elements in the Human Body Sodium and its Role in the Human Body Potassium and its Role in the Human Body Calcium and its Role in the Human Body Iron and its Role in the Human Body Sodium and Its Role in the Human Body  Sodium and Its Role in the Human Body Fluid and Electrolyte Balance: Sodium: ~0.2% Sodium is crucial in maintaining fluid balance, as water follows sodium through osmosis. Sodium levels in blood influence the distribution of water across cell membranes, maintaining the body's overall hydration status. Nerve Impulse Transmission: Sodium is essential for nerve function. Nerve impulses are generated by changes in sodium (Na⁺) and potassium (K⁺) ion gradients across the cell membrane. This process, called depolarization, is critical for transmitting signals in the nervous system. Key Process: Sodium-Potassium Pump (Na⁺/K⁺-ATPase) The sodium-potassium pump actively transports Na⁺ ions out of cells and K⁺ ions into cells, maintaining electrochemical gradients.  Key Reactions Involving Sodium Sodium-Potassium Pump Reaction: The Na⁺/K⁺-ATPase pump is vital in maintaining cell membrane potential, which is crucial for nerve and muscle cell function. ATP hydrolysis powers this pump, moving Na⁺ and K⁺ ions against their concentration gradients. Equation Sodium and Acid-Base Balance: Sodium also plays a role in acid-base balance through the exchange of sodium and hydrogen ions in the kidneys, helping to maintain blood pH.  Health and Disease Implications of Sodium Hyponatremia (Sodium Deficiency): Hyponatremia occurs when sodium levels in the blood are too low, often due to excessive water intake, kidney issues, or certain medications. Low sodium levels disrupt fluid balance and cellular function, particularly in the brain. Symptoms of Hyponatremia: Headache, confusion, seizures, and, in severe cases, coma. Medical Conditions: Syndrome of inappropriate antidiuretic hormone secretion (SIADH), kidney disease, and congestive heart failure.  Health and Disease Implications of Sodium Hypernatremia (Excess Sodium): Hypernatremia occurs when blood sodium levels are abnormally high, often due to dehydration, excessive sodium intake, or loss of water through illness. High sodium levels cause cells to lose water, leading to cellular dehydration. Symptoms of Hypernatremia: Thirst, confusion, muscle twitching, and, in severe cases, seizures. Medical Conditions: Dehydration, diabetes insipidus, and excessive salt intake.  Sodium's Role in Disease Mechanisms Hypertension (High Blood Pressure): Excess sodium intake can lead to hypertension by increasing blood volume, which raises blood pressure. Over time, high blood pressure can damage the cardiovascular system, increasing the risk of heart disease, stroke, and kidney disease. Congestive Heart Failure: In congestive heart failure, the heart cannot effectively pump blood, leading to fluid retention. Sodium levels are crucial in managing fluid balance in these patients. High sodium intake worsens fluid retention, placing extra strain on the heart. Kidney Disease: The kidneys regulate sodium balance. In chronic kidney disease, sodium excretion is impaired, leading to fluid retention and hypertension. Managing sodium intake is critical to preventing complications in these patients.  Sodium in Clinical Settings Intravenous (IV) Sodium Solutions: In medical settings, IV sodium solutions (e.g., normal saline) are used to restore fluid and electrolyte balance in patients with dehydration, electrolyte imbalances, or hypotension. Diuretics: Diuretics are used to reduce sodium levels and fluid retention in patients with hypertension or heart failure. They help the kidneys excrete excess sodium, which lowers blood volume and reduces blood pressure.  Sodium (Na) Measurement Method: Sodium is measured in blood serum or plasma, similar to potassium, using ion-selective electrodes or flame photometry. Lab Techniques: Ion-Selective Electrode (ISE): Detects sodium concentration in blood. Flame Photometry: Quantifies sodium ions. Potassium and its Role in the Human Body  Potassium and its Role in the Human Body The Role of Potassium in the Human Body Potassium: ~0.4% Maintenance of Membrane Potential: Potassium ions (K⁺) help establish the resting membrane potential in cells, particularly in excitable cells like neurons and muscle cells. The movement of potassium across cell membranes is fundamental to cellular excitability and function. Nerve Impulse Transmission: Potassium works alongside sodium to generate action potentials, which are electrical signals that transmit information along nerves. When neurons are stimulated, potassium exits the cell, restoring the resting membrane potential after an action potential. Muscle Contraction: Potassium is necessary for muscle contraction, including the heart. Proper potassium levels ensure rhythmic contractions in the heart, and imbalances can disrupt the heart’s electrical rhythm.  Key Reactions Involving Potassium Sodium-Potassium Pump (Na⁺/K⁺-ATPase): The Na⁺/K⁺- ATPase pump is essential for maintaining potassium and sodium gradients across the cell membrane. This pump moves three sodium ions out of the cell and two potassium ions into the cell, using ATP as an energy source. Equation: ​ This gradient is essential for cell excitability, nerve impulse transmission, and muscle contractions. Acid-Base Balance: Potassium ions play a role in acid-base regulation through their exchange with hydrogen ions (H⁺) in cells. In conditions of acidosis (low pH), potassium is exchanged with H⁺ ions to help buffer blood pH.  Health and Disease Implications of Potassium Hypokalemia (Potassium Deficiency): Hypokalemia is a condition characterized by low potassium levels in the blood, often due to fluid loss (e.g., vomiting, diarrhea) or certain medications (e.g., diuretics). Low potassium disrupts cellular functions, particularly in muscle and nerve cells. Symptoms of Hypokalemia: Muscle weakness, cramps, arrhythmias, fatigue, and, in severe cases, paralysis. Medical Conditions: Hypokalemia is commonly seen in patients with kidney disease, metabolic alkalosis, and patients using diuretics.  Health and Disease Implications of Potassium Hyperkalemia (Excess Potassium): Hyperkalemia occurs when potassium levels in the blood are elevated, often due to kidney dysfunction or medication use (e.g., potassium-sparing diuretics). Excess potassium disrupts the resting membrane potential, affecting the heart and other muscles. Symptoms of Hyperkalemia: Muscle fatigue, weakness, numbness, arrhythmias, and in severe cases, cardiac arrest. Medical Conditions: Common in chronic kidney disease, adrenal insufficiency, and patients taking potassium-sparing diuretics or ACE inhibitors.  Potassium’s Role in Disease Mechanisms Cardiovascular Disorders: Both hyperkalemia and hypokalemia can significantly impact cardiovascular health. Abnormal potassium levels can lead to arrhythmias, with hyperkalemia being particularly dangerous as it can cause life-threatening cardiac arrest. Renal Dysfunction: The kidneys regulate potassium balance, so impaired kidney function often leads to hyperkalemia. In chronic kidney disease, the kidneys are less able to excrete potassium, requiring dietary and medical management to prevent complications. Muscle Weakness and Paralysis: Potassium is vital for muscle function. Severe imbalances can cause muscle weakness, cramps, and even paralysis, impacting both skeletal and smooth muscles, as seen in gastrointestinal and respiratory systems.  Potassium in Clinical Settings Potassium Replacement Therapy: In hypokalemia, potassium supplements or intravenous potassium may be administered to restore normal levels. This must be carefully monitored, as rapid potassium administration can cause hyperkalemia. Potassium-Binding Agents: In cases of hyperkalemia, potassium-binding agents (e.g., sodium polystyrene sulfonate) may be used to reduce potassium levels by promoting its excretion through the gastrointestinal tract. Diuretics: Certain diuretics (e.g., loop and thiazide diuretics) cause potassium loss, while potassium-sparing diuretics prevent potassium excretion. Diuretic choice and dosage must be carefully considered based on a patient’s potassium levels and underlying conditions.  Potassium (K) Measurement Method: Potassium is measured in blood serum or plasma using ion- selective electrodes or flame photometry. Lab Techniques: Ion-Selective Electrode (ISE): Detects potassium concentration in blood. Flame Photometry: Quantifies potassium ions in solution. Calcium and its Role in the Human Body  Calcium and its Role in the Human Body The Role of Calcium in the Human Body Calcium: ~1.5% Bone and Teeth Structure: Calcium combines with phosphate to form hydroxyapatite crystals, which provide rigidity and strength to bones and teeth. Hydroxyapatite Formation:Ca10(PO4)6(OH)2. This mineral compound is critical for skeletal structure and dental health. Blood Clotting: Calcium ions are required in several steps of the coagulation cascade, facilitating the formation of blood clots to prevent bleeding.  Calcium and Its Role in the Human Body The Role of Calcium in the Human Body Muscle Contraction: Calcium ions (Ca²⁺) play a central role in muscle contraction. When a muscle cell is stimulated, calcium is initiating the interaction between actin and myosin for contraction. Nerve Transmission: Calcium is essential in nerve impulse transmission. Ca²⁺ ions enter nerve terminals, allowing communication between neurons.  Key Reactions Involving Calcium Calcium and Phosphate Balance: Calcium and phosphate levels in the body are closely regulated to prevent abnormal bone deposition and ensure cellular function. The balance between calcium and phosphate is controlled by hormones, particularly parathyroid hormone (PTH) and vitamin D. Calcium Signaling Pathways: Calcium ions act as secondary messengers in various signaling pathways, influencing cellular functions such as metabolism, gene expression, and apoptosis..  Health and Disease Implications of Calcium Hypocalcemia (Calcium Deficiency): Hypocalcemia is characterized by low calcium levels in the blood, which can disrupt muscle and nerve function. Symptoms of Hypocalcemia: Muscle cramps, tingling in the extremities, spasms (tetany), and, in severe cases, seizures. Medical Conditions: Commonly seen in hypoparathyroidism, vitamin D deficiency, and chronic kidney disease.  Health and Disease Implications of Calcium Hypercalcemia (Excess Calcium): Hypercalcemia occurs when blood calcium levels are abnormally high. This condition can lead to kidney stones, bone pain, and neurological symptoms. Symptoms of Hypercalcemia: Fatigue, nausea, constipation, confusion, and, in severe cases, cardiac arrhythmias. Medical Conditions: Hyperparathyroidism, malignancies (e.g., bone cancer), and excessive vitamin D intake.  Calcium’s Role in Disease Mechanisms Osteoporosis: Osteoporosis is a condition characterized by reduced bone density, increasing fracture risk. It often results from calcium and vitamin D deficiencies, hormonal changes, or aging, Leading to bone demineralization. Hypoparathyroidism: Hypoparathyroidism results in low PTH levels, impairing calcium regulation and causing hypocalcemia. This condition may be due to surgical removal of the parathyroid glands, autoimmune disorders, or genetic factors. Kidney Stones: Elevated calcium levels can lead to the formation of calcium oxalate or calcium phosphate kidney stones, particularly in patients with hyperparathyroidism or excessive calcium supplementation.  Calcium in Clinical Settings Calcium Supplementation: In cases of hypocalcemia or osteoporosis, calcium supplements may be administered to restore normal levels and support bone health. Supplementation should be monitored to avoid hypercalcemia and other complications. Calcium Channel Blockers: Calcium channel blockers are medications used to treat hypertension and certain arrhythmias by inhibiting calcium entry into cells, relaxing blood vessels, and reducing heart workload. Iron and its Role in the Human Body  Iron and its Role in the Human Body The Role of Iron in the Human Body Oxygen Transport: Iron is a central component of hemoglobin, the protein in red blood cells responsible for oxygen transport. Hemoglobin binds oxygen in the lungs and carries it to tissues where it is released for cellular respiration. Hemoglobin Structure: Hemoglobin contains heme groups, each with an iron ion (Fe²⁺) at its center, which reversibly binds oxygen: Hb + O2 HbO2​  Iron and Its Role in the Human Body The Role of Iron in the Human Body Energy Production (Electron Transport Chain): Iron is a key component facilitating ATP production. DNA Synthesis and Cell Growth: Iron is necessary for DNA synthesis. This makes iron essential for cell division and growth, particularly in rapidly dividing cells like red blood cells.  Key Reactions Involving Iron Heme Synthesis: The synthesis of heme, an iron-containing molecule, is essential for forming hemoglobin and certain enzymes. This process occurs in the mitochondria and cytoplasm of developing red blood cells. Iron Storage and Transport: Iron is stored in the body as ferritin and transported by transferrin in the bloodstream. Health and Disease Implications of Iron Iron Deficiency (Iron Deficiency Anemia): Iron deficiency is the most common cause of anemia worldwide, occurring when there is insufficient iron to produce adequate hemoglobin. This reduces oxygen transport to tissues, impairing cellular metabolism and energy production. Symptoms of Iron Deficiency: Fatigue, weakness, pale skin, shortness of breath, and, in severe cases, cognitive impairments. Medical Conditions: Common in cases of poor dietary intake, blood loss, gastrointestinal disorders, and increased iron requirements during pregnancy. Health and Disease Implications of Iron Iron Overload (Hemochromatosis): Iron overload can lead to toxicity, as excess iron generates free radicals that damage tissues. Hemochromatosis, a genetic disorder, causes excessive iron absorption and accumulation, particularly in the liver, heart, and pancreas. Symptoms of Iron Overload: Joint pain, abdominal pain, fatigue, diabetes, and, in severe cases, liver cirrhosis or heart failure. Medical Conditions: Primary hemochromatosis (genetic) and secondary iron overload due to repeated blood transfusions or excessive supplementation. Iron’s Role in Disease Mechanisms Anemia of Chronic Disease: In chronic diseases like cancer or infections, iron metabolism is disrupted as part of an immune response to limit iron availability to pathogens. This results in functional iron deficiency, where iron is sequestered in storage sites and not utilized for erythropoiesis. Iron and Oxidative Stress: Excess iron can participate in Fenton reactions, where Fe²⁺ reacts with hydrogen peroxide (H₂O₂) to produce hydroxyl radicals ( OH), a type of reactive oxygen species that can damage cellular components. Fenton Reaction:Fe2+ + H2O2→Fe3+ + OH− +OH  Iron in Clinical Settings Iron Supplementation: In cases of iron deficiency anemia, oral or intravenous iron supplements are prescribed. Treatment requires careful monitoring to prevent iron overload and side effects like gastrointestinal discomfort. Phlebotomy and Chelation Therapy: For patients with iron overload, therapeutic phlebotomy (blood removal) or iron-chelating agents (e.g., deferoxamine) are used to reduce iron levels, particularly in conditions like hemochromatosis or transfusion-induced iron overload. 1.What is the main function of iron in the human body? 2.What is the primary function of calcium in the body? 3.What condition can result from long- term calcium deficiency? 1.What is the main function of Na+ in the human body? 2.What is the primary function of K+ in the body?