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47 Cards in this Set
- Front
- Back
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TBW/TBWt men: women: |
men: ~ 60% women: ~ 50% everyone 50-70% |
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Volume of ICF relative to TBW |
2/3 of TBW ICF containes ~2x the solute as ECF, therefore 2x H2O due to equilibrium between two compartements. |
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Volume of ECF relative to TBW |
1/3 TBW |
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TBW = ? |
TBW = ECF + ICF |
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ECF = ? |
ECF = ISF + plasma + minor fluid compartments (transcellular fluid, usually ignored) |
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An increase in adipose tissues = ______ in percent body water? |
decrease in percent body water |
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What drives the movement of H2O between ICF and ECF? |
Osmotic pressure gradients ICF and ECF are in osmotic equilibrium d/t the high permeability to water of most cell membranes |
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What is ISF? |
ISF is ultrafiltrate of plasma across the capillary walls "fluid bathing cells" |
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What is permeable to ISF? What is impermeable to ISF? |
Permeable to small ions Impermeable to proteins Therefore, ISF contains little protein. Plasma has protein. |
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Blood Volume = |
Total volume of intravascular compartment Plasma + blood cells (erythrocytes, leukocytes, and platelets) |
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Transcellular Fluid |
trapped in small compartments surrounded with epithelial cells i.e. cerebrospinal fluid surrounding brain and spinal cord, synovial fluid, intraoccular fluid, digestive secretions, ect. usually ignored in this context. |
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Why do plasma proteins affect ion concentrations of plasma and ISF? |
they occupy space (they are large) and are negatively charged |
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What is the % TBW and typical volume in L of a 70 kg man? a 70 kg female? |
Men: 60% of BW, 42L Women: 50% of BW, 35L |
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TBW loss daily with normal activities? |
~1-2 L/day (~2.5 -5% TBW) |
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TBW loss daily with perspiration with normal activities? with exertion in hot, dry weather? |
normal: 1 - 2 L/day hot/dry: 1 to 3 L/hour |
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TBW loss daily with urination?
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1 - 2 L/day |
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TBW loss daily with defecation?
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0.1 L/day severe diarrhea can increase to 25 L over 24 period (~60% TBW) |
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All body fluids are? |
electrically neutral |
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Major cation of ECF? |
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Major cation of ICF |
K+ |
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Asymmetric distribution of Na+ and K+ maintain metabolic energy via? |
Na+-K+-ATPase |
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Two major anions of the ECF? |
Cl- and HCO3- (are excluded from the ICF due to negative membrane potential and weak active transport mechanisms) |
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Major anions of ICF? |
Proteins and organic phosphates (Pi) |
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Why is the ionic composition of ISF and Plasma similar? |
Because the capillary endothelium is freely permeable to small ions. |
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Why are proteins excluded from ISF? |
Because endothelium is not permeable to proteins. |
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why is there a slight difference in the concentration of small solutes between plasma and ISF? ie cation concentration of protein-free solution of ISF is lowered by ~5% and the anion conc. is ~5% higher compared to plasma |
*plasma proteins occupy space, make all solutes more concentrated in remaining water *plasma proteins in plasma carry a negative charge. (attract cations into plasma from ISF and repel anions out of plasma into ISF) |
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Why is the total solute concentration (osmolality) the same in ICF and ECF? |
Because cell membranes are very permeable to H2O, if transient differences in osmolality occur between the two, water quickly equilibrates between the two compartments. |
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Why is the osmolality of plasma 1.3 mOs/L greater than the osmolality of ISF? |
Due to plasma protein per se and slight excess of permeable ions |
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Proteins occupy ___ % of plasma volume? |
7% |
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Equivalent |
describes the amount of charged (ionized) solute and is the number of moles multiplied by the valence of the solute. |
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Plasma (mM) Na+ K+ Ca2+ Mg2+ Cl- HCo3- |
Na+ 142 K+ 4.4 Ca2+ 1.2 ionized, 2.5 total Mg2+ 0.6 ionized, 0.9 total Cl- 102 HCo3- 22 |
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Plasma H2PO4- and HPO2 4- Proteins Glucose pH Osmolality |
H2PO4- and HPO2 4- 0.7 mM ionized, 1.4 total
Proteins 1 mmole/L, 14 meq/L, 7 g/dl Glucose 5.5 mM pH 7.4 Osmolality 291 mosmole/kg H2O |
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Protein free Plasma (mM)
Na+ K+ Ca2+ Mg2+ Cl- HCo3- |
Na+ 153
K+ 4.7 Ca2+ 1.3 ionized Mg2+ 0.6 ionized Cl- 110 HCo3- 24 |
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Protein -Free Plasma H2PO4- and HPO2 4- Proteins Glucose pH Osmolality |
H2PO4- and HPO2 4- 0.75 ionized
Proteins ---- Glucose 5.9 pH 7.4 Osmolality 290 |
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ISF (mM) Na+ K+ Ca2+ Mg2+ Cl- HCo3- |
Na+ 145
K+ 4.5 Ca2+ 1.2 ionized Mg2+ 0.55 ionized Cl- 116 HCo3- 25 |
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ISF H2PO4- and HPO2 4- Proteins Glucose pH Osmolality |
H2PO4- and HPO2 4- 0.8 ionized
Proteins 1 g/dl Glucose 5.9 mM pH 7.4 Osmolality 290 mosmole/kg H2O |
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ICF (mM) Na+ K+ Ca2+ Mg2+ Cl- HCo3- |
Na+ 15
K+ 120 Ca2+ 10^ -7 M (ionized) Mg2+ 1 ionized, 18 total Cl- 20 HCo3- 15 |
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ICF H2PO4- and HPO2 4- Proteins Glucose pH Osmolality |
H2PO4- and HPO2 4- 0.7 ionized Proteins 30 g/dl Glucose very low pH ~7.2 Osmolality 290 |
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Anion gap |
*difference in major cation and anion conc in plasma *norm = 9-14 meq/L * = [Na+]pl - ([Cl-]pl + [HCO3-]pl) |
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What counter balances the tendency of water drawn into capillaries due to the higher osmolality of plasma? |
Hydrostatic pressure in the capillaries |
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Steps to calculate percentage problem i.e. pt drank a cup of water, she weighs 60 kg, how much % of her TBW did she drink? |
1. find her TBW in L 2. convert cups (2 cups = 1 pint, 2 pints = quart, 1 quart = 1L) 3. cross calculate |
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Total osmolality = |
[2] [Na] + glucose/18 + BUN/2.8 |
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Tonicity = |
[2] [Na] + glucose/18 |
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Protein- free plasma correction factor for 7% plasma = |
divid amount by 0.93 |
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Protein - free plasma correction factor if plasma &/or Lipids = 20% |
divid by 0.8 |
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In cell, potassium is important for? |
electrical properties in cell |
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In cell, sodium is important in? |
Volume control |
