Micronutrient Metabolism: Electrolytes, Vitamins, and Minerals Review

What are the major intracellular ions?

K+ (Potassium), Mg2+ (Magnesium)

What are the major extracellular ions?

Na+ (Sodium), Cl- (Chloride), Ca2+ (Calcium), HCO3- (Bicarbonate)

What is the formula for calculating the Anion Gap?

Anion Gap = (Na+ + K+) - (Cl- + HCO3-)

What is the normal range for Anion Gap?

10-20 mmol/L

What is the role of RAAS in electrolyte regulation?

Increases Na+ reabsorption, Cl- reabsorption, water retention, K+ excretion, blood volume, and blood pressure.

Where is sodium primarily filtered and reabsorbed in the nephron?

Freely filtered at the glomerulus; reabsorbed mainly in the proximal convoluted tubule.

What regulates potassium levels in the body?

RAAS and aldosterone.

What is the normal range for sodium (Na+)?

136-145 mmol/L

What is the normal range for potassium (K+)?

3.5-5.1 mmol/L

What is the normal range for chloride (Cl-)?

98-107 mmol/L

What is the normal range for bicarbonate (HCO3-)?

23-29 mmol/L

What is the primary function of sodium (Na+)?

Controls blood osmolality and blood volume.

What is the primary function of potassium (K+)?

Neuromuscular excitability and muscle contraction.

What is the primary function of chloride (Cl-)?

Maintains acid-base balance and blood buffering.

What is the primary function of bicarbonate (HCO3-)?

Regulates acid-base balance.

What is the primary function of magnesium (Mg2+)?

Enzyme activation and ATP phosphate-transfer reactions.

What is the primary function of calcium (Ca2+)?

Bone and teeth formation, neuromuscular excitability.

What is the primary function of phosphorus?

Bone and teeth formation, glucose metabolism.

How does increased ADH affect sodium concentration?

Increased ADH leads to increased water reabsorption, which dilutes plasma and decreases Na+ concentration.

How does decreased ADH affect sodium concentration?

Decreased ADH leads to less water retention, concentrating plasma and increasing Na+ concentration.

What is the effect of PTH on calcium and phosphate?

Increases calcium reabsorption and decreases renal phosphate reabsorption.

What is the role of calcitonin?

Lowers blood calcium levels by inhibiting bone resorption.

What is the major regulation mechanism for sodium?

Kidney regulation via RAAS, aldosterone, and ADH.

What is the major regulation mechanism for potassium?

Kidney regulation via RAAS and aldosterone.

What is the major regulation mechanism for chloride?

Generally follows sodium regulation by the kidneys.

What is the major regulation mechanism for calcium?

Regulated by PTH, calcitriol (Vitamin D), and calcitonin.

What is the major regulation mechanism for magnesium?

GI absorption and kidney regulation, influenced by PTH.

What is the major regulation mechanism for phosphorus?

Regulated by PTH, Vitamin D, and FGF23.

What is the effect of increased renin?

Increased angiotensin II, increased aldosterone and ADH, increased Na+/water retention, and increased K+ excretion.

What happens when renin decreases?

Opposite effect of increased renin.

What does increased aldosterone do?

Increases Na+/Cl- reabsorption, increases water retention, and increases K+ excretion, leading to decreased blood K+.

What is the effect of decreased aldosterone?

Less Na+ retention and less K+ excretion, leading to increased blood K+.

What is the effect of increased Parathyroid Hormone (PTH)?

Increases blood Ca2+ and decreases blood phosphorus.

What are the effects of PTH on renal function?

Increases renal Ca2+ reabsorption, decreases renal phosphorus reabsorption, activates Vitamin D, and supports Mg2+ reabsorption.

What does increased calcitonin do?

Decreases blood calcium, decreases bone resorption, and increases calcium and phosphorus excretion.

What is the controlling mechanism for maintaining high intracellular potassium concentration?

Na+/K+ ATPase pump.

What occurs during the Chloride Shift at tissues?

CO2 enters RBC, forms H2CO3, dissociates into H+ and HCO3-, H+ binds hemoglobin, HCO3- leaves RBC, and Cl- enters RBC.

What occurs during the Chloride Shift at lungs?

HCO3- enters RBC, Cl- leaves RBC, CO2 is regenerated and exhaled.

What are the components of a total Carbon Dioxide measurement in plasma?

HCO3-, dissolved CO2, carbamino compounds, and carbonic acid (H2CO3).

How is osmolality calculated?

Calculated Osmolality = (1.86 x Na) + (Glucose / 18) + (BUN / 2.8) + 9.

What is the normal serum osmolality range?

275-295 mOsm/kg.

What causes increased serum osmolality?

Increased sodium, glucose, BUN, and water loss/dehydration.

What role does Vitamin D play in mineral concentrations?

Increases intestinal absorption of calcium, phosphorus, and magnesium.

What is the role of osteoblasts?

Bone-forming cells; responsible for bone formation/ossification.

What is the role of osteoclasts?

Bone resorption; break down bone matrix and release mineral salts.

What is the effect of increased osteoclast activity on blood calcium levels?

Increases blood calcium due to more bone breakdown.

What is the effect of decreased osteoclast activity on blood calcium levels?

Decreases blood calcium due to less bone breakdown.

What are the general functions of iron in the body?

Respiration and oxygen transport, allows hemoglobin to bind oxygen, important in myoglobin, participates in redox reactions, and is part of enzymes/proteins involved in metabolism.

What is the major tissue source of iron in the body?

Hemoglobin in red blood cells; major storage tissues include the liver, spleen, and bone marrow.

What are the sources/pools of iron within the body?

Hemoglobin, myoglobin, tissue enzymes, plasma transferrin, ferritin, hemosiderin, liver, spleen, and bone marrow.

What is the process of iron absorption?

Dietary Fe3+ is reduced to Fe2+ and absorbed into intestinal enterocyte.

What happens to iron inside the enterocyte?

Iron may be stored as ferritin or leave the cell through ferroportin.

What is the transport form of iron in the blood?

Fe3+ bound to transferrin.

What is the role of hepcidin in iron homeostasis?

Regulates iron homeostasis; increased hepcidin decreases serum iron, while decreased hepcidin increases serum iron.

What is the function of ferritin?

Major storage form of iron; stores iron in a readily available form.

What is the role of transferrin in iron transport?

Carries ferric iron (Fe3+) through the blood.

What defines a trace element?

A mineral required by the body in very small amounts.

What are the characteristics of an essential element?

Required for normal body function, has a specific biological function, deficiency causes abnormal function or disease, and replacing it corrects the deficiency.

What are the functions of copper?

Enzyme/coenzyme roles, iron metabolism, and metalloproteins.

What are the dietary sources of copper?

Organ meats, nuts, grains, and protein-containing foods.

What are the functions of zinc?

RNA/DNA synthesis, enzyme structure/activity, protein metabolism, skeletal metabolism, immune reactions, insulin storage/release.

What are the dietary sources of zinc?

Meat and protein-rich foods.

What can deficiency impair?

Growth, healing, immunity, and enzyme activity.

What is the role of Selenium?

Antioxidant defense; component/cofactor of glutathione peroxidase.

How does Selenium help the body?

Protects against free radicals and participates in thyroid hormone metabolism.

What are the sources of Selenium?

Food and drinking water.

How is Selenium excreted?

In urine, feces, and sweat.

What is the role of Chromium?

Supports metabolism of glucose, fat, and cholesterol; promotes insulin action.

What are the sources of Chromium?

Dietary intake.

What is the role of Manganese?

Component of metalloenzymes and an enzyme activator.

What affects the absorption of Manganese?

Iron, calcium, phosphates, and fiber.

What is the absorption rate of Molybdenum?

About 25-80% of dietary intake is absorbed.

What are common dietary sources of Vitamin D?

Sunlight/UVB, oily fish, egg yolks, liver, fortified foods.

What are common dietary sources of Vitamin A?

Liver, yellow/orange fruits, leafy vegetables, fish, milk.

What are common dietary sources of Vitamin K?

Leafy green vegetables, eggs, liver; some made by intestinal bacteria.

What are common dietary sources of Vitamin E?

Fruits/vegetables, meat, vegetable oils, unprocessed cereals, nuts, seeds.

What are common dietary sources of Vitamin C?

Fruits (especially citrus) and vegetables.

What are common dietary sources of Vitamin B1?

Brown rice, vegetables, potatoes, liver, eggs.

What are common dietary sources of Vitamin B2?

Green vegetables, bananas, dairy.

What are common dietary sources of Vitamin B3?

Meat, fish, eggs, vegetables, mushrooms, nuts.

What are common dietary sources of Vitamin B5?

Meat, vegetables, broccoli, avocados, grains.

What are common dietary sources of Vitamin B6?

Meat, bananas, vegetables, nuts.

What are common dietary sources of Vitamin B7?

Eggs, organ meats, yeast, milk.

What are common dietary sources of Vitamin B9?

Leafy vegetables, fortified cereal/bread/pasta, liver.

What are common dietary sources of Vitamin B12?

Meat and animal products.

What are the differences between fat-soluble and water-soluble vitamins?

Fat-soluble: A, D, E, K; absorbed with dietary fat. Water-soluble: B vitamins + C; dissolve in water.

What vitamins are fat-soluble?

A, D, E, K.

What vitamins are water-soluble?

B1, B2, B3, B5, B6, B7, B9, B12, C.

What is the common name for Vitamin D?

Cholecalciferol.

What is the common name for Vitamin A?

Retinol / retinal / retinoic acid.

What is the common name for Vitamin K?

Phylloquinones / menaquinones / menadiones.

What is the common name for Vitamin E?

Tocopherols / tocotrienols.

What is the common name for Vitamin B1?

Thiamine.

What is the common name for Vitamin B2?

Riboflavin.

What is the common name for Vitamin B3?

Niacin.

What is the common name for Vitamin B5?

Pantothenic acid.

What is the common name for Vitamin B6?

Pyridoxine.

What is the common name for Vitamin B7?

Biotin.

What is the common name for Vitamin B9?

Folate.

What is the common name for Vitamin B12?

Cobalamin.