Cell volume Regulation

Question 1

• How do uncharged substances move?
• Osmotic pressure will either?
• 3 mechanisms used to keep cell from swelling?
  1? Problem? Way cells get around this? Ex? (2)
  2? What is opposing osmotic force? Problem? Ex? (3)
  3? Def? Ex?
• Diffusion?
• Osmosis?

Answer 1

• According to conc. gradient
• shrink/swell a cell
  1. ) Impermeable to water; difficult for cell division without water; water diffuse at very slow rate; kidney and sweat glands
  2. ) Strong cell wall; hydrostatic force; energetically expensive; plants; fungi, bacteria
  3. ) Balance osmotic force in and out; solute molecules in solute solution; animal cells
• Water movement via random, thermal agitated forces; way water bumps into cell membrane
• Movement across smeipermeable membrane due to solute concentrations

Question 2

Reflection coefficient:

• Same as water = ? Totally impermeable = ?
• 0.5 means?
• Clinical examples?(2)
• Osmolarity?
• Molarity?
• Equivalents?
• Tonicity? Depends on? 2 types?

Answer 2

• 0; 1
• exerts 1/2 ideal osmotic pressure of a non-permeating solute
• Shock with blood to extremities but not brain; glucose is less permeable which temporarily pulls water out before helping it back in
• Conc. of solute particles; CaCL2 = 3 osM
• Moles of solute/Liter solution
• mosM x valence of that ion
• Effect of a solution on the cell; permeability of membrane; hypertonic and hypotonic