Fluid Balances

What percentage of lean body weight does water make up in men?

Approximately 60%.

What percentage of lean body weight does water make up in women?

Approximately 50%.

What are the main components of extracellular fluid?

Intravascular (25%) and interstitial (75%) components.

What are the two types of fluid compartments in the human body?

Intracellular fluid and extracellular fluid.

What is osmosis?

The movement of water across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.

What causes edema?

Accumulation of fluid within the interstitial spaces due to increased capillary hydrostatic pressure, decreased plasma oncotic pressure, increased capillary permeability, or lymph obstruction.

What is hyponatremia?

A serum sodium level less than 135 mEq/L.

What is hyperkalemia?

A potassium level greater than 5.5 mEq/L.

What effects does hyponatremia have on the body?

Cerebral edema, lethargy, confusion, seizures, and hypotension.

What are the normal serum sodium levels?

135-145 mEq/L.

What hormones control sodium and water balance?

Renin-angiotensin-aldosterone system and natriuretic peptides.

Define hypernatremia.

A serum sodium level greater than 145 mEq/L.

What role does ADH (antidiuretic hormone) play in water balance?

ADH increases water reabsorption into the plasma.

What is the normal serum calcium concentration range?

8.5 to 10.5 mg/dl.

What causes hypercalcemia?

Hyperparathyroidism, bone metastases, excess vitamin D, and certain tumors.

What is hypomagnesemia?

A serum magnesium level less than 1.8 mEq/L.

What symptoms are associated with hypermagnesemia?

Muscle weakness, nausea, hypotension, and respiratory distress.

What is the function of potassium in the body?

It regulates intracellular electrical neutrality and is essential for nerve impulse transmission and muscle contraction.

What are common causes of hypokalemia?

Reduced intake of potassium, increased entry of potassium into cells, and increased loss of potassium.

What system detects plasma sodium levels and regulates water retention?

The renal system.

What is the treatment for hypochloremia?

Treat the underlying cause, often linked to hyponatremia or elevated bicarbonate levels.

What is the primary function of water in the body?

To act as a solvent, regulate body temperature, and facilitate biochemical reactions.

What percentage of total body weight is water in infants?

About 75%.

What is the main source of water in the body?

Ingestion of fluids and foods, and metabolic processes.

What happens during dehydration?

There is an excessive loss of water relative to solute in the body.

Name a consequence of severe dehydration.

Kidney failure and electrolyte imbalances.

What is the thirst mechanism?

A physiological response to dehydration that stimulates the urge to drink.

What is the significance of plasma osmolality?

It indicates the concentration of solutes in the blood and helps regulate fluid balance.

What two fluids comprise total body water?

Intracellular and extracellular fluids.

How does the body primarily lose water?

Through urine, sweat, and respiration.

What role does aldosterone play in fluid balance?

Aldosterone promotes sodium retention, which helps to retain water.