Sodium, Potassium, and Chloride Lecture Flashcards

A comprehensive set of vocabulary flashcards covering the physiological roles, requirements, clinical assessments, and regulatory mechanisms of the electrolytes sodium, potassium, and chloride.

Sodium (Na+)

A principal extracellular cation that regulates fluid balance, blood pressure, nerve transmission, muscle contraction, and nutrient absorption.

Potassium (K+)

The primary intracellular cation essential for maintaining cell function, normal heart rhythms, muscle contraction, and blood pressure regulation.

Chloride (Cl-)

The major extracellular anion that works with sodium to maintain osmotic pressure, helps regulate acid-base balance, and is a component of gastric hydrochloric acid ($HCl$).

Sodium AI ($19-50$ years)

The Adequate Intake level set at $1,500\,mg$ per day.

Chronic Disease Risk Reduction (CDRR) for Sodium

The intake level set at $2,300\,mg$ per day, which also serves as the Upper Limit ($UL$).

Potassium AI ($19+$ years)

The Adequate Intake level set at $3,400\,mg$ for males and $2,600\,mg$ for females per day.

Chloride AI ($19-50$ years)

The Adequate Intake level set at $2,300\,mg$ (or $2.3\,g$) per day.

Hyponatremia

A condition defined by serum sodium levels below $135\,mEq/L$, which may indicate fluid overload, excessive diuretic use, or specific disease states like heart failure.

Hypernatremia

A condition defined by serum sodium levels above $145\,mEq/L$, suggesting dehydration, high sodium intake with insufficient fluid, or diabetes insipidus.

Hypokalemia

A potassium deficiency characterized by serum levels below $3.5\,mEq/L$ and symptoms such as muscle weakness, cramps, fatigue, and cardiac arrhythmias.

Hyperkalemia

Elevated serum potassium levels (above $5.0\,mEq/L$) that can lead to cardiac arrest; often caused by Chronic Kidney Disease ($CKD$) or potassium-sparing diuretics.

Renin-Angiotensin-Aldosterone System (RAAS)

A hormonal system triggered by decreased $ECF$ volume or blood pressure that results in sodium retention and potassium excretion to restore balance.

Aldosterone

A hormone produced in the adrenal cortex that promotes sodium reabsorption and potassium excretion in the kidneys.

Vasopressin (ADH)

A hormone from the hypothalamus that increases water reabsorption in the kidneys and stimulates thirst in response to increased $ECF$ osmolarity.

Na+/glucose cotransport system

An intestinal absorption pathway where a carrier on the brush border membrane transports sodium together with solutes like glucose, amino acids, or B vitamins.

Electroneutral Na+ and Cl- absorption

A transport mechanism where $Na+/H+$ exchange works in concert with a $Cl-/HCO_3$ exchange to bring both sodium and chloride into the enterocyte.

Electrogenic Na+ absorption

A process where sodium enters the luminal membrane through a $Na+$ channel, driven by a concentration gradient and accompanied by water and anions.

Na+/K+-ATPase pump

A basolateral membrane pump that uses energy up to maintain a low intracellular $Na+$ concentration and creates the electrical gradient for absorption.

Metabolic Alkalosis

An acid-base imbalance that can be caused by chloride deficiency resulting from excessive gastrointestinal losses like vomiting.

Normal Serum Sodium Range

The clinical range of $135-145\,mEq/L$, reflecting hydration status and fluid balance.

Normal Serum Potassium Range

The clinical measure reflecting extracellular potassium, typically ranging from $3.5-5.0\,mEq/L$.

Normal Serum Chloride Range

The clinical measure of chloride typically ranging from $101$ to $111\,mEq/L$.