Water Balance & Osmoregulation

Flashcards covering definitions and key terms related to water balance and osmoregulation.

Osmosis

Diffusion from an area of high water concentration to low.

Osmotic Pressure

Hydrostatic pressure that exactly counterbalances the osmotic movement of water.

Hyperosmotic

Refers to a solution with low solute concentration.

Hyposmotic

Refers to a solution with high solute concentration.

Osmoregulators

Organisms that maintain internal fluid composition regardless of surroundings.

Osmoconformers

Organisms that conform to osmotic pressure of their surroundings.

Ionoregulators

Organisms that maintain different concentrations of some ions inside and outside.

Euryhaline

Animals that tolerate a wide range of salt concentrations.

Stenohaline

Animals that tolerate a narrow range of salt concentrations.

Intracellular fluid (ICF)

Fluid contained within cells.

Extracellular fluid (ECF)

Fluid located outside of cells, including interstitial fluid and plasma.

Nephron

The functional unit of the kidney involved in osmoregulation.

U/P ratio

Ratio used to analyze osmotic pressure of urine compared to plasma.

Isosmotic urine

Urine with osmotic pressure equal to that of plasma.

Hyposmotic urine

Urine that is more dilute than plasma.

Hyperosmotic urine

Urine that is more concentrated than plasma.

Cutaneous Water Loss

Water lost through the skin.

Respiratory Water Loss

Water lost through respiratory surfaces.

Uric Acid

A nitrogenous waste product produced by reptiles and birds that requires low water.

Ammonia

A highly toxic nitrogenous waste produced by fishes.

Urea

A moderately toxic nitrogenous waste produced by amphibians and mammals.