Human fluid metabolism: Difference between revisions
imported>Howard C. Berkowitz (New page: {{TOC|right}} At the most basic, the physiology of '''human fluid metabolism''' splits into the '''extracellular fluid compartment''' and the '''intracellular fluid compartment'''. Even wi...) |
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[[Image:Fluids V1.png|thumb|left|500px|Basic compartments]] | |||
At the most basic, the physiology of '''human fluid metabolism''' splits into the '''extracellular fluid compartment''' and the '''intracellular fluid compartment'''. Even with that separation, there is a constant exchange of water, ions, and non-ionized substances between the compartments and subcompartments. <ref name=Guyton>{{citation | At the most basic, the physiology of '''human fluid metabolism''' splits into the '''extracellular fluid compartment''' and the '''intracellular fluid compartment'''. Even with that separation, there is a constant exchange of water, ions, and non-ionized substances between the compartments and subcompartments. <ref name=Guyton>{{citation | ||
| title = Guyton and Hall Textbook of Medical Physiology | | title = Guyton and Hall Textbook of Medical Physiology | ||
| Line 8: | Line 10: | ||
| isbn = 072168677X | | isbn = 072168677X | ||
}}pp. 2-4</ref> | }}pp. 2-4</ref> | ||
==Electrolytes== | |||
In virtually all fluids, not just the concentration, but the ratios of four principal ions are critical:<ref name=Preston>{{citation | |||
| author = Richard A. Preston | | author = Richard A. Preston | ||
| title=Acid-Base, Fluids and Electrolytes Made Ridiculously Simple | | title=Acid-Base, Fluids and Electrolytes Made Ridiculously Simple | ||
| Line 20: | Line 20: | ||
| year = 2002 | | year = 2002 | ||
| isbn = 0940780313}}, p. 5</ref> | | isbn = 0940780313}}, p. 5</ref> | ||
*Sodium (Na<sup>+</sup>) and potassium (K<sup>+</sup>) | |||
*Chloride (Ca<sup>+2</sup>) and bicarbonate (HCO<sub>3</sub><sup>+</sup> | |||
Several other ions and molecules also are important, but sodium:potassium balance, for example, is fundamental to cell electrical activity. | |||
{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
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| 10-20 mg/dL | | 10-20 mg/dL | ||
|} | |} | ||
At this point in the diagram, we only distinguish between plasma and interstitial fluid, not urine, lymph, sweat, and other fluids within the extracellular compartment. | |||
==Blood versus fluid== | |||
Again as a basic idea, [[blood]] is plasma that carries blood cells and additional circulating chemicals. Many clinical measurements involving blood chemistry are made on the easier-to-collect blood serum, which is the fluid remaining after blood clots. Serum does not circulate in the body, although it can accumulate near blood clots. | |||
==References== | ==References== | ||
{{reflist|2}} | {{reflist|2}} | ||
Latest revision as of 11:46, 12 January 2010
At the most basic, the physiology of human fluid metabolism splits into the extracellular fluid compartment and the intracellular fluid compartment. Even with that separation, there is a constant exchange of water, ions, and non-ionized substances between the compartments and subcompartments. [1]
Electrolytes
In virtually all fluids, not just the concentration, but the ratios of four principal ions are critical:[2]
- Sodium (Na+) and potassium (K+)
- Chloride (Ca+2) and bicarbonate (HCO3+
Several other ions and molecules also are important, but sodium:potassium balance, for example, is fundamental to cell electrical activity.
| Substance | Extracellular volume | Intracellular volume |
|---|---|---|
| Sodium | 135-145 mEq/L | 10-20 mEq/L |
| Potassium | 3.5-5.0 mEq/L | 130-140 mEq/L |
| Chloride | 95-105 mEq/L | |
| Bicarbonate | 22-26 mEq/L | |
| Glucose | 90-120 mg/dL | |
| Calcium | 8.5-10 mg/dL | |
| Magnesium | 1.4-2.1 mg/dL | 20-30 mEqL |
| Urea nitrogen | 10-20 mg/dL | 10-20 mg/dL |
At this point in the diagram, we only distinguish between plasma and interstitial fluid, not urine, lymph, sweat, and other fluids within the extracellular compartment.
Blood versus fluid
Again as a basic idea, blood is plasma that carries blood cells and additional circulating chemicals. Many clinical measurements involving blood chemistry are made on the easier-to-collect blood serum, which is the fluid remaining after blood clots. Serum does not circulate in the body, although it can accumulate near blood clots.
References
- ↑ Arthur C. Guyton and John E. Hall, ed. (2000), Guyton and Hall Textbook of Medical Physiology, vol. Tenth Edition, W. B. Saunders, ISBN 072168677Xpp. 2-4
- ↑ Richard A. Preston (2002), Acid-Base, Fluids and Electrolytes Made Ridiculously Simple, McMaster, ISBN 0940780313, p. 5