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Unformatted text preview: gender Figure 5-25: Distribution of volume in the 25: body fluid compartments body 5.4) Osmosis & Osmotic 5.4) Osmosis Osmotic Equilibrium Equilibrium
1. W ater freely crosses Water membranes membranes 2. Osmotic pressure (mm Hg, atm) Osmotic atm 3. Osmolarity
– Molarity x # particles in particles solution/molecule (osm/L) solution/molecule 4. Osmolality – using body wt.
– Milliosmoles solute/kg water 5. Comparing two solutions
a) Isosmotic (same) b) Hyperosmotic (more) c) Hyposmotic (less) Figure 5-26: Osmosis and osmotic pressure 6 2/2/2010 A. Tonicity: How a Cell A. Tonicity Reacts in a Solution Reacts
• Depends on Depends osmolarity, but also osmolarity but permeability of permeability of solutes solutes
– = measure of the measure effect on the cell !!! effect • Penetrating solute • Non-penetrating solute
******************** 1) Isotonic cell same 2) Hypertonic cell shrivels 28a, 3) Hypotonic cell swells Figure 5-28a, b: Tonicity depends on the relative concentrations of nonpenetrating solutes nonpenetrating Tonicity: How a Cell Tonicity: Reacts in a Solution Reacts
• Penetrating solutes Penetrating can move and disrupt the chemical / osmotic equilibrium!! osmotic Figure 5-28c, d: Tonicity depends 28c, on the relative concentrations of nonpenetrating solutes nonpenetrating 7 2/2/2010 B. Electrical Disequilibrium
• Separation of charged ions
– Membrane insulates – Potential = stored energy; required to keep charges separate Potential stored – Conduction of signal...
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- Spring '09