Biochemistry: Electrolyte Hydric Balance

Biochemistry and Electrolyte Hydric Balance

• Body Composition in Water varies across age and sex. Infants have a higher proportion of water than adults. Women tend to have less water than men due to higher fat content. Aging is associated with decreased water content, which is amplified by increased adipose tissue and reduced muscle mass.

• Body Fluids are primarily water, the solvent for essential solutes. The total body water is divided into intracellular and extracellular compartments. Extracellular fluids include plasma and interstitial fluid. Intracellular fluids are contained within cells.

• Electrolytes are inorganic substances that dissociate into ions in solutions, vital for neural and muscle function, fluid balance, and physiological processes. Key electrolytes include sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium (Mg2+).

• Water Balance: Intake encompasses liquids, food, and metabolic water. Losses occur via urine, skin/respiration, sweat, and feces. Hormones like ADH, Aldosterone, Angiotensin II, and ANP regulate water balance.

• Water Balance Disorders: Dehydration results from increased electrolyte concentration; excessive intake leads to hypotonic hydration with diluted extracellular fluids, potentially causing cerebral edema.

• Electrolyte Patterns: Extracellular fluids have high sodium, whereas intracellular fluids contain high potassium; each compartment has a unique electrolytic composition.

• Anion Gap: A calculation used clinically to help identify metabolic acidosis, with a normal range of ~12 mEq/L.

• Sodium (Na+): Key role in neuromuscular function and membrane potential. Variations, hypernatremia or hyponatremia, are tied to disorders impacting renal failure, acidosis, and other factors. Symptoms vary from neurologic deficits in cases of high-sodium levels to weakness and arrhythmias with low sodium. Its regulation is critical.

• Potassium (K+): Crucial for neuromuscular activity and bone/teeth mineralization. Imbalances (hypokalemia or hyperkalemia) are associated with various conditions including renal losses, alkalosis, or cell damage, causing issues ranging from muscle weakness to potentially fatal cardiac effects.

• Calcium (Ca²+): Essential for enzyme activation, metabolism, and cardiac function. Imbalances arise from conditions like hyperparathyroidism; symptoms include tissue calcifications for high levels, and neurological depression for low levels.

• Magnesium (Mg²+): Important for enzyme function and neuromuscular activity. Magnesium imbalances (hypermagnesemia, hypomagnesemia) are observed with renal failure, magnesium-containing drugs, or other conditions; the consequences are diverse and can include tissue dysfunction or neurologic effects.