Fluid

Intracellular fluid (ICF)

Fluid located within cells, accounts for approximately two-thirds of the body's total fluid.

Extracellular fluid (ECF)

Fluid located outside of cells, accounts for the remaining one-third of the body's total fluid.

Body fluid

Refers to body water and its dissolved substances.

Thirst

The primary control mechanism triggered by dehydration indicating the need for water.

Renin-angiotensin II pathway

A mechanism that stimulates the hypothalamic thirst center in response to decreased blood volume and pressure.

Metabolic water

Water produced through aerobic cellular respiration, reflecting the body's ATP demand.

Fluid intake regulation

Adjustment of water consumption as the main method to maintain water balance in the body.

Dehydration

Occurs when water loss surpasses water gain, triggering thirst.

Aldosterone

Hormone that increases sodium (Na+) reabsorption in the kidneys.

ANP (Atrial Natriuretic Peptide)

Hormone that increases sodium (Na+) excretion in urine.

Osmolarity

A measure of solute concentration in body fluids, affecting water movement between compartments.

Fluid imbalance

Occurs due to changes in osmolarity, often from shifts in Na+ and Cl- concentrations.

Water intoxication

Condition resulting from consuming water faster than kidneys can eliminate it.

Electrolytes

Minerals in body fluids that help regulate fluid balance, osmotic pressure, and pH.

Calcium (Ca2+)

The body's most abundant mineral, primarily serving as an extracellular ion.

Buffer systems

Mechanisms that prevent rapid shifts in pH of body fluids by converting strong acids and bases into weak ones.

Protein buffer system

The most prevalent buffer in intracellular fluid and plasma, particularly effective in red blood cells.

Carbonic acid-bicarbonate buffer system

A key regulator of blood pH that utilizes bicarbonate ion.

Phosphate buffer system

Important for regulating pH within red blood cells and kidney tubular fluids.

Metabolic alkalosis

Condition characterized by high bicarbonate levels due to nonrespiratory acid depletion.

Body fluid percentage

Body fluids make up about 55-60% of the total body weight in lean adults.

Fluid balance

Achieved when body compartments hold the correct quantity of water based on specific requirements.

Osmosis

The movement of water driven by differences in solute concentration.

Hypertonic extracellular fluid

Condition where extracellular fluid has a higher solute concentration than intracellular fluid.

Hypotonic extracellular fluid

Condition where extracellular fluid has a lower solute concentration than intracellular fluid.

Sodium (Na+)

An important ion that affects osmolarity and fluid balance in the body.

Chloride (Cl-)

An ion primarily responsible for osmolarity and fluid balance in the extracellular environment.

Acid-base balance

Essential maintenance of pH within the normal range for cellular function.

Water movement regulation

Electrolytes regulate the movement of water between fluid compartments through osmosis.

Enzyme cofactors

Ions that act as necessary components for optimal enzyme activity.

pH range of systemic arterial blood

Normal pH range is between 7.35 and 7.45.

Hydrogen ions (H+)

Excessive levels lead to acidity, requiring regulation to restore pH balance.

Bicarbonate ions (HCO3-)

Excessive levels lead to alkalinity, necessitating regulation to return pH to normal.

Fluid compartments

Different sections of body fluids, categorized as intracellular and extracellular.

Daily water loss

Typically equals daily water gain under normal circumstances.

Osmotic pressure

The pressure required to prevent the movement of water across a semipermeable membrane.

Fluid rehydration

Process of replenishing body fluids after loss.

Body dehydration

State of insufficient water in the body leading to physiological changes.

Kidney function

Regulates the excretion of excess water and electrolytes to maintain fluid balance.

Electrolyte imbalances

Disruptions in the normal concentrations of electrolytes in the body fluids.

Body fluid compartments

Includes blood plasma, interstitial fluid, and lymph as part of extracellular fluid.

Principle of osmosis

Movement of water from areas of low solute concentration to areas of high concentration.

Physiological roles of calcium

Roles in blood coagulation, neurotransmitter release, muscle tone maintenance, and nervous system excitability.