Fluid

Intracellular Fluid (ICF)

The fluid located inside cells, accounting for approximately two-thirds of the body's total fluid.

Extracellular Fluid (ECF)

The fluid located outside the cells, making up the remaining one-third of the body's total fluid.

Thirst Mechanism

Triggered by dehydration, this mechanism controls water intake to maintain fluid balance.

Renin-Angiotensin II Pathway

A hormonal pathway that stimulates the thirst center in the hypothalamus in response to decreased blood volume and pressure.

Metabolic Water

Water produced through aerobic cellular respiration, which is proportional to the body's ATP demand.

Dehydration

A condition in which water loss exceeds water gain, triggering thirst.

Osmolarity

The measure of solute concentration in body fluids that affects water movement between compartments.

Buffer Systems

Systems that prevent rapid changes in pH by converting strong acids and bases into weak ones.

Protein Buffer System

The most prevalent buffer in intracellular fluid and plasma, effective in maintaining blood pH.

Carbonic Acid-Bicarbonate Buffer System

A key regulator of blood pH relying on the bicarbonate ion.

Hypertonic Extracellular Fluid

Fluid with a higher solute concentration than intracellular fluid, causing cells to shrink.

Hypotonic Extracellular Fluid

Fluid with a lower solute concentration than intracellular fluid, causing cells to swell.

Electrolytes

Ions that regulate water movement, acid-base balance, and electrical activity in body fluids.

Acid-Base Balance

The mechanism of maintaining pH within a narrow range essential for normal cellular function.

Acidosis

A condition characterized by a decrease in pH, often from the accumulation of acids.

Alkalosis

A condition characterized by an increase in pH, generally due to excessive bicarbonate.

Water Intoxication

A disturbance in brain function that results when the balance of electrolytes is altered by rapid intake of water.