Plasma osmolarity

Plasma Osmolarity is a measure of the concentration of solutes in the blood plasma. It is a crucial aspect of homeostasis, as it influences the movement of water between body compartments and the overall balance of water and solutes in the body.

Definition

Plasma osmolarity is defined as the total concentration of solute particles per liter of plasma. It is typically measured in milliosmoles per liter (mOsm/L). The normal range for plasma osmolarity in humans is approximately 275 to 295 mOsm/L.

Measurement

Plasma osmolarity can be measured directly through laboratory tests, or it can be estimated using a formula that takes into account the concentrations of various solutes in the plasma, including sodium, glucose, and urea (also known as blood urea nitrogen or BUN).

Regulation

The body maintains plasma osmolarity within a narrow range through a variety of mechanisms. These include the release of antidiuretic hormone (ADH) from the pituitary gland, which promotes water reabsorption in the kidneys, and the sensation of thirst, which encourages water intake.

Clinical Significance

Abnormal plasma osmolarity can indicate a variety of health conditions. High plasma osmolarity (hyperosmolarity) can result from dehydration, diabetes, or the excessive consumption of salt or protein. Low plasma osmolarity (hypoosmolarity) can result from overhydration, liver disease, or certain hormonal disorders.

See Also

• Osmosis
• Osmotic pressure
• Osmoregulation
• Hyponatremia
• Hypernatremia

This physiology-related article is a stub. You can help WikiMD by expanding it.