Starling equation

(noun)

An equation that illustrates the role of hydrostatic and oncotic forces in the movement of fluid across capillary membranes.

Related Terms

Examples of Starling equation in the following topics:

  • Movement of Fluid Among Compartments

    • Movement of fluid among compartments depends on several variables described by Starling's equation.
    • The Starling equation defines the forces across a semipermeable membrane and allows calculation of the net flux.
    • The solution to the equation is known as the net filtration or net fluid movement.
    • This equation has a number of important physiologic implications, especially when disease processes grossly alter one or more of the variables.
    • According to Starling's equation, the movement of fluid depends on six variables :

  • Regulation of Glomerular Filtration Rate

    • The Starling equation for GFR is GFR=Filtration Constant X (Hydrostatic Glomerulus Pressure-Hydrostatic Bowman's Capsule Pressure)-(Osmotic Glomerulus Pressure+Osmotic Bowman's Capsule Pressure).
    • Under normal conditions, albumins cannot be filtered into the Bowman's capsule, so the osmotic pressure in the Bowman's space is generally not present, and is removed from the GFR equation.

  • Capillary Dynamics

    • The movement of materials across the capillary wall is dependent on pressure and is bi-directional depending on the net filtration pressure derived from the four Starling forces which modulate capillary dynamics.
    • There are four forces, termed Starling forces, which modulate capillary dynamics.

  • Bulk Flow: Filtration and Reabsorption

    • The movement of materials across the capillary wall is dependent on pressure and is bi-directional depending on the net filtration pressure derived from the four Starling forces.

  • Cardiac Output

    • Blood volume itself is another regulated variable, and it is regulated slowly through complex processes in the renal system, that will alter blood pressure based on the Starling mechanism.

  • Resting Membrane Potentials

    • The interactions that generate the resting potential are modeled by the Goldman equation.
    • The three ions that appear in this equation are potassium (K+), sodium (Na+), and chloride (Cl−).
    • Goldman equation: R is the universal gas constant, equal to 8.314 joules·K−1·mol−1 T is the absolute temperature, measured in kelvins (= K = degrees Celsius + 273.15) F is the Faraday constant, equal to 96,485 coulombs·mol−1 or J·V−1·mol−1

  • Adherens Junctions

    • If you were to remove calcium from the equation, this type of cell junction would disintegrate as a result. 

  • Acidosis

    • Metabolic acidosis is compensated for in the lungs, as increased exhalation of carbon dioxide promptly shifts the buffering equation to reduce metabolic acid.
    • The Henderson-Hasselbalch equation is useful for calculating blood pH, because blood is a buffer solution.

  • Sodium, Electrolytes, and Fluid Balance

    • In humans, the most common type of dehydration by far is isotonic (isonatraemic) dehydration which effectively equates with hypovolemia; but the distinction of isotonic from hypotonic or hypertonic dehydration may be important when treating people with dehydration.

  • Factors Affecting Pulmonary Ventilation: Airway Resistance

    • Below is the equation for calculating airway resistance (R).