Sodium, Potassium and Chloride Lecture Notes

Flashcards covering the functions, dietary requirements, absorption mechanisms, and clinical implications of sodium, potassium, and chloride as discussed in the lecture.

Sodium Adequate Intake (AI)

adults $19-50$ years = $1,500\,\text{mg}$.

Potassium Adequate Intake (AI)

$3,400\,\text{mg}$ for males and $2,600\,\text{mg}$ for females aged $19+$ years.

Chloride Adequate Intake (AI)

For adults aged $19-50$ years, the value is $2,300\,\text{mg}$.

Chronic Disease Risk Reduction (CDRR) Level for Sodium

Set at $2,300\,\text{mg}$ per day.

Chloride Upper Limit (UL)

The maximum daily intake is recommended not to exceed $3,600\,\text{mg}$.

Normal Serum Sodium Range

The standard clinical range is $135-145\,\text{mEq/L}$, reflecting hydration status and fluid balance.

Hyponatremia

A condition where serum sodium is below $135\,\text{mEq/L}$, which may indicate fluid overload, SIADH, or excessive diuretic use.

Hypernatremia

A condition where serum sodium is above $145\,\text{mEq/L}$, suggesting dehydration, diabetes insipidus, or high sodium intake with insufficient fluid.

Normal Serum Potassium Range

The most common clinical measure for potassium is approximately $3.5-5.0\,\text{mEq/L}$.

Hypokalemia

Low biochemical values of potassium characterized by muscle weakness, cramps, fatigue, constipation, and cardiac arrhythmias.

Hyperkalemia

Elevated potassium levels that can lead to numbness, tingling, nausea, and cardiac arrest; often caused by CKD or potassium-sparing diuretics.

Normal Serum Chloride Range

The clinical range used for nutriture assessment is $101-111\,\text{mEq/L}$.

Sodium/Glucose Cotransport System

One of the three pathways of sodium absorption where a carrier on the brush border membrane of the enterocyte transports sodium into the cell along with a solute such as glucose or amino acids.

Electroneutral $Na^+$ and $Cl^-$ Cotransport System

An absorption pathway where $Na^+/H^+$ exchange works in concert with a $Cl^-/HCO_3^-$ exchange to move both ions into the enterocyte.

Electrogenic Sodium Absorption

A mechanism where sodium enters the luminal membrane via a $Na^+$ channel by diffusing inwardly via a concentration gradient.

$Na^+/K^+\text{-ATPase}$ Pump

An energy-dependent pump on the basolateral membrane that moves $Na^+$ out of the cell and $K^+$ into the cell to maintain electrical gradients.

Renin

An enzyme released by the Juxtaglomerular apparatus of the kidney in response to decreased ECF volume or blood pressure.

Angiotensin II

A potent vasoconstrictor that triggers aldosterone release, increases fluid intake, and results in increased ECF volume.

Aldosterone

A hormone from the adrenal cortex that increases sodium reabsorption and potassium excretion.

Vasopressin

Also known as antidiuretic hormone (ADH), it is released by the hypothalamus to increase water reabsorption in the kidney.

Primary Functions of Sodium

Includes fluid balance and blood pressure regulation, nerve transmission, muscle contraction, and nutrient absorption.

Primary Functions of Potassium

Includes maintaining intracellular fluid volume, nerve transmission, muscle contraction (especially cardiac), acid-base balance, and blood pressure regulation.

Primary Functions of Chloride

Serves as a primary anion for electrolyte balance, acid/base balance, digestion ($HCl$), immune response (phagocytes), and osmotic regulation.

Dietary Sources of Sodium

Table salt, processed foods, snack foods, cured meats, seafood, condiments, milk, cheese, and bread.

High-Potassium Food Examples

Dried apricots ($1,100\,\text{mg}$ per half cup), medium potato with skin ($620-730\,\text{mg}$), and butternut squash soup ($500-600\,\text{mg}$ per cup).