HSCI 103 CHAPTER 25: Fluid, Electrolyte, and Acid-Base Balance

Vocabulary-style flashcards covering fluid compartments, electrolyte regulation, and acid-base balance mechanisms based on Chapter 25 lecture notes.

Extracellular Fluid (ECF)

The body fluid compartment composed of plasma and interstitial fluid.

Intracellular Fluid (ICF)

The fluid compartment located inside the cells.

Electrolytes

Compounds that dissociate into ions in water, possessing greater osmotic power than nonelectrolytes.

Nonelectrolytes

Substances such as glucose, lipids, creatinine, and urea that do not dissociate in water.

$Na^+$ and $K^+$ Pumps

ATP-dependent cellular mechanisms that maintain nearly opposite concentrations of sodium and potassium in the ECF and ICF.

Hypothalamic osmoreceptors

Sensory receptors that detect ECF osmolality and are activated by changes in plasma osmolality of $1 - 2\%$, dry mouth, or decreased blood volume.

Maintenance Osmolality

The level at which body fluid osmolality is typically maintained, approximately $300\,mOsm$.

Hyponatremia

A condition of hypotonic hydration characterized by low ECF $Na^+$ concentration.

Edema

The accumulation of fluid in the interstitial space, also known as pitting edema.

Sodium ($Na^+$)

The most significant solute determining total body water and the distribution of fluid in compartments.

Atrial Natriuretic Peptide (ANP)

A hormone triggered by increased blood pressure that inhibits renin, aldosterone, and ADH to promote $Na^+$ and water excretion.

Potassium ($K^+$)

The most abundant cation in the ICF, essential for resting membrane potentials and hearth function.

Calcium

The most abundant mineral in the body, primarily found in bones and involved in neurotransmitter release and muscle contraction.

Parathyroid hormone

A hormone that enhances the reabsorption of Calcium from filtrate.

Calcitonin

A hormone that removes Calcium from plasma via osteoblasts.

Acidemia

A condition where blood pH is less than $7.35$.

Alkalemia

A condition where blood pH is greater than $7.45$.

Respiratory Acidosis

A condition resulting from hypoventilation where $CO_2$ and $H^+$ levels increase, often caused by lung disease or CNS depression.

Respiratory Alkalosis

A condition resulting from hyperventilation where $CO_2$ and $H^+$ levels decrease, often caused by panic attacks or sepsis.

Metabolic Acidosis

An acid-base abnormality characterized by low levels of $HCO_3^-$.

Metabolic Alkalosis

An acid-base abnormality characterized by high levels of $HCO_3^-$.

Renal Compensations

The process by which the kidneys adjust $HCO_3^-$ and $H^+$ to compensate for acid-base imbalances.