Water, Electrolyte, and Acid-Base Balance Practice Flashcards

This set of vocabulary flashcards covers the fundamental concepts of water distribution, electrolyte regulation, and acid-base balance mechanisms as described in Chapter 21.

The Balance Concept

The requirement for homeostasis where the amounts of water and electrolytes entering the body equal the amounts exiting.

Intracellular Fluid Compartment (ICF)

The fluid contained within cells, comprising approximately 63% of total body water.

Extracellular Fluid Compartment (ECF)

The fluid outside of cells, comprising approximately 37% of total body water, including plasma and interstitial fluid.

Hydrostatic pressure

The pressure that drives fluid out of plasma and into lymphatic vessels.

Osmotic pressure

The pressure that regulates fluid movement into and out of cells and causes the return of fluid to the plasma.

Metabolic water

Water produced as a by-product of the oxidative metabolism of nutrients, accounting for about 10% of daily water intake.

Osmoreceptors

Sensors in the hypothalamus that shrink during dehydration to trigger the thirst center and swell with excess water to inhibit it.

Antidiuretic Hormone (ADH)

A hormone signaled by the hypothalamus and released by the posterior pituitary that increases water reabsorption in the kidneys.

Aldosterone

A hormone that regulates electrolyte balance by increasing $Na^+$ reabsorption and causing the secretion of excess $K^+$ into the urine.

Calcitonin

A hormone that decreases blood calcium levels by targeting distal kidney tubules to secrete excess $Ca^{2+}$ and inhibiting osteoclast activity.

Parathyroid hormone

A hormone that increases blood calcium levels by stimulating kidney reabsorption, activating osteoclasts, and increasing intestinal absorption of $Ca^{2+}$.

Acids

Electrolytes that ionize in water to release hydrogen ions ($H^+$).

Bases

Substances that release ions which combine with hydrogen ions ($H^+$), thereby lowering their concentration in body fluids.

Bicarbonate Buffer System

The primary ECF buffer system composed of carbonic acid ($H_2CO_3$) and bicarbonate ($HCO_3^-$).

Phosphate Buffer System

A buffer system important for regulating the pH of intracellular fluid (ICF) and renal tubules using dihydrogen phosphate ($H_2PO_4^-$) and hydrogen phosphate ($HPO_4^{2-}$).

Protein Buffer Systems

Buffer systems involving the carboxyl ($-COOH$) and amino ($-NH_2$) ends of proteins, such as hemoglobin and plasma proteins.

Acidosis

A physiological condition where the pH of body fluids drops below 7.4.

Alkalosis

A physiological condition where the pH of body fluids rises above 7.4.

Respiratory Acidosis

An imbalance resulting from increased levels of carbon dioxide and carbonic acid often caused by factors interfering with pulmonary ventilation.

Metabolic Acidosis

An imbalance resulting from the accumulation of non-respiratory acids or the loss of bases.

Respiratory Alkalosis

An imbalance resulting from hyperventilation, leading to a loss of carbon dioxide ($CO_2$) and carbonic acid ($H_2CO_3$).

Metabolic Alkalosis

An imbalance resulting from a great loss of hydrogen ions ($H^+$) or a gain of bases, often manifesting as a decrease in breathing rate.