Fluid, Electrolyte, and Acid Balance

These flashcards cover key concepts related to fluid balance, electrolyte balance, and acid-base balance in the human body.

Intracellular fluid (ICF)

About 2/3 of body water, located inside cells.

Extracellular fluid (ECF)

About 1/3 of body water, includes plasma, interstitial fluid, and other fluids.

Plasma

The fluid part of blood.

Interstitial fluid (IF)

Fluid located between cells.

Osmotic pressure

The pressure that pulls water in the direction of higher solute concentration.

Hydrostatic pressure

The pressure that pushes water out of compartments.

Electrolytes

Salts, acids, and bases that have greater osmotic power than nonelectrolytes.

Nonelectrolytes

Substances like glucose and lipids that do not pull water as strongly.

Sodium (Na+)

The main cation in extracellular fluid responsible for osmotic pressure.

Chloride (Cl-)

The main anion in extracellular fluid.

Potassium (K+)

The main cation in intracellular fluid.

Phosphate (PO4-3)

The main anion in intracellular fluid.

Na+/K+ ATPase pump

Maintains opposite electrolyte patterns between ICF and ECF.

Osmolality

The concentration of solutes in body fluids.

Water intake sources

Includes ingested fluids (60%), solid food (30%), and metabolic water (10%).

Water output

Includes urine (60%), insensible losses (28%), sweat (8%), and feces (4%).

Thirst center

Located in the hypothalamus and regulates water intake.

ADH (antidiuretic hormone)

Hormone that makes kidney collecting ducts permeable to water.

Dehydration

Condition where water loss exceeds intake, leading to symptoms like dry mouth and low urine output.

Hypotonic hydration

Condition caused by too much water intake, resulting in water moving into cells.

Edema

Fluid buildup in the interstitial space due to various causes.

Aldosterone

Hormone that causes kidneys to reabsorb sodium and water follows.

ANP (Atrial natriuretic peptide)

Opposes aldosterone, promotes sodium and water excretion.

Estrogens

Hormones that increase sodium reabsorption.

Progesterone

Hormone that decreases sodium reabsorption.

Glucocorticoids

Hormones that increase sodium reabsorption.

Hyperkalemia

Condition of excessively high potassium levels in the blood.

Hypokalemia

Condition of excessively low potassium levels in the blood.

PTH (parathyroid hormone)

Hormone that increases blood calcium levels.

Calcitonin

Hormone that lowers blood calcium levels with a minor effect in adults.

Acidosis

Condition with a pH less than 7.35.

Alkalosis

Condition with a pH greater than 7.45.

Bicarbonate buffer system

Main buffer system in ECF that helps regulate pH.

Respiratory buffering

Involves lungs adjusting CO2 levels to regulate pH.

Renal buffering

Kidneys help regulate pH by eliminating metabolic acids and reabsorbing bicarbonate.

Hypoventilation

Shallow breathing that can lead to respiratory acidosis.

Hyperventilation

Rapid breathing that can lead to respiratory alkalosis.

Metabolic acidosis

Condition characterized by low blood pH and low bicarbonate levels.

Metabolic alkalosis

Condition characterized by high blood pH and high bicarbonate levels.

Respiratory compensation

Lungs adjust breathing to compensate for metabolic imbalances.

Renal compensation

Kidneys adjust bicarbonate reabsorption/secretion to compensate for respiratory imbalances.

PCO2 levels

Indicator of respiratory function; abnormal levels point to respiratory acidosis or alkalosis.

HCO3 levels

Indicator of metabolic balance; abnormal levels indicate acidosis or alkalosis.

Infants' water content

Highest at birth (70-80%), declines to 58% in adulthood.

Aging effects on hydration

Elderly individuals may not feel thirsty and are at risk for dehydration.

High risk groups for dehydration

Very young and very old populations.

Kidney functions

Regulate water and electrolyte balance.

Water balance regulation

Involves both intake and output mechanisms.

Fluid compartments

Total body fluid volume is approximately 40 liters, accounting for 60% of body weight.

Interstitial space

The area where fluid accumulates outside of blood vessels.

Kidney tubules

Structure that plays a key role in sodium reabsorption and potassium secretion.

Regulatory hormones

Various hormones that influence electrolyte levels and balance.

Fluid leaks

Fluid can leak out of blood vessels but is returned by lymphatic vessels.

Cerebrospinal fluid

One of the fluids classified under extracellular fluid.

Lymphatic fluid

Fluid that assists in returning excess interstitial fluid back to circulation.

Osmotic gradients

Determines the direction of water movement across compartments.

Renin-angiotensin pathway

Mechanism activated by low blood pressure leading to aldosterone release.

Cell volume regulation

Controlled primarily by sodium and chloride levels.

Blood pressure regulation

Affected by sodium levels and cardiac output.