fluid balance

Body Water Composition

50-60% of our body is made up of water, with fluid composition decreasing with age.

Intracellular Fluid

Fluids found inside cells, comprising ⅔ of all body fluids.

Extracellular Fluid

Fluids located outside of cells, including interstitial fluid and blood plasma.

Osmotic Gradient

The difference in solute concentration that drives fluid movement between compartments.

Electrolytes

Substances that dissociate into ions in solution, critical for creating osmotic potential.

Non-electrolytes

Substances that do not dissociate into ions in solution, such as glucose and lipids.

Water Intake Methods

Water enters the body through ingestion, metabolic water production, and moisture in food.

Fluid Exchange Mechanism

Osmotic gradient is vital for fluid movement between interstitial and intracellular fluids.

Sodium's Role in Fluid Balance

Most sodium is found in extracellular compartments and is key for maintaining water balance.

Aldosterone Function

Hormone that increases sodium reabsorption in kidneys, raising blood pressure.

Bicarbonate Buffer System

A chemical buffer system that maintains blood pH by accepting or donating hydrogen ions.

Acidosis

A condition where blood pH is below 7, can be respiratory or metabolic.

Alkalosis

A condition where blood pH is above 7, can be respiratory or metabolic.

Kidneys in Acid-Base Regulation

Regulate hydrogen and bicarbonate ion concentrations, affecting blood pH.

Osmoreceptors

Sensory receptors in the hypothalamus that detect changes in plasma osmolality.

Buffering Systems

Includes bicarbonate, phosphate, and proteins, temporarily stabilizing pH changes.

Fluid Balance Homeostasis

Maintained by feedback mechanisms that regulate water intake and output.

Cardiovascular Baroreceptors

Monitors blood pressure and send signals to adjust kidney function, affecting sodium balance.

Metabolic Water Production

Water generated through oxidative reactions during metabolism.

Resistance to pH Change

Chemical buffer systems resist pH change temporarily; physiological systems address it permanently.