Anybody have a good source to help me understand Resting Membrane Potential?
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Guyton's Human Physiology is probably the best physiology book for med students
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try looking in my sources, that site helps me a lot with everything i hope it helps you too!
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this is the best i could find. i looked everywhere on the web and found nothing. hope someone else can help more.\nhttp://www.ifafitness.com/health/loadcalc.htm
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www.springerlink.com/index/V865UG7GQ737QR35.pdf\nhttp://scholar.google.com/scholar?q=membranes+in+refinery+gas+processes&hl=en&lr=
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Balance Your Body Chemistry.\n\nIf you've ever taken chemistry in high school you're familiar with this simple experiment to test the conductivity of salt. Two ends of an electrical wire are attached to a light bulb. The other ends are submerged in a glass of water. Because water alone is not conductive, the bulb does not light up. But when we add a little salt to the water the bulb starts to glow.\n\nIt's the same with our body. When we lack the natural elements in salt we suffer from a chronic energy deficit, or deficit of information. Salt is a core essential nutrient with exceptional abilities and qualities fundamental for keeping us alive.\n\nScience and medicine have tried to define the precise roles of salt in the healthy and diseased human organism. Blood, sweat, and tears all contain salt, and both the skin and the eyes are protected from infectious germs by the anti-bacterial effect of salt. When salt is added to a liquid, particles with opposite charges are formed: a positively charged sodium ion and a negatively charged chloride ion. This is the basis of osmosis which regulates fluid pressure within living cells and protects the body against excessive water loss (as in diarrhoea or on heavy sweating).  Sodium and chloride ions, as well as potassium ions, create a measurable difference in potential across cell membranes. This ensures that the fluid inside living cells remains separate from that outside. Thus, although the human body consists mainly of water, our "inner ocean" does not flow away or evaporate. Sodium ions create a high pressure of liquid in the kidneys and thus regulate their metabolic function. Water is extracted through the renal drainage system. The body thus loses a minimal amount of essential water. Out of 1500 litres of blood which pass daily through the kidneys, only about 1.5 litres of liquid leave the body as urine. \n\nSalt is "fuel" for nerves. Streams of positively and negatively charged ions send impulses to nerve fibres. A muscle cell will only contract if an impulse reaches it. Nerve impulses are partly propelled by co-ordinated changes in charged particles.
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When you have weak electrolytes, (equillibria in general) you should make the following table.\n\n1. write the reaction\n\nHNO2 <=> H+ + NO2-\n\n2.Put the initial amounts (expressed as concentration) of each molecule. In this case we have only the concentration of HNO2, so\n\n.. .. .. .. .. .. HNO2 <=> H+ + NO2-\nInitial .. .. .. .. 0.5\n\n3.Assume that an unknown amount "x" of the reactants react.\nThen write also how much of each product you expect to be produced according to the stoichiometry. In this case 1 mole of HNO2 gives one mole of H+  and NO2-, so x mole/L HNO2 will  give x mole/L of each and our table becomes\n\n.. .. .. .. .. .. HNO2 <=> H+ + NO2-\nInitial .. .. .. .. 0.5\nDissociate .. ..x\nProduce .. .. .. .. .. .. .. ..x .. .. .x\n\n4. Ka is an expression for the concentrations at equilibrium. So let's see what are those. For the reactants you will have initial-what reacted. We have only HNO2 with 0.5-x. For the products it will be the initial+what was produced. We didn't have any intial so it is only what was produced (x for both of the products). Thus the table in its final form is \n\n.. .. .. .. .. .. HNO2 <=> H+ + NO2-\nInitial .. .. .. .. 0.5\nDissociate .. ..x\nProduce .. .. .. .. .. .. .. ..x .. .. .x\nAt Equil. .. .. 0.5-x .. .. .. x .. .. .x\n\nKa= [H+][NO2-]/[HNO2] = x^2/(0.5-x)\nNow you either solve the quadratic equation and find x, or we assume that 0.5 >>x and practically 0.5-x=0.5.\nThen Ka=x^2/0.5=4*10^-14 =>\nx=squareroot(2*10^-14)= 1.4*10^-7. It is much smaller than 0.5 so our assumption is valid (otherwise we would have to solve the quadratic and get an exact solution).\n\nFor a simple level of chemistry we would now say\npH=-log[H+]= -logx =-log(1.4*10^-7) = 6.85\n\nHowever for more advanced and accurate expectations we see that the H+ coming from HNO2 is found to be in the same order of magnitude as that coming from the self dissociation of water (10^-7 for distilled water). Therefore in this case we cannot ignore the self dissociation of water (as we usually do) for calculating the pH. \nThere are 2 approaches for this case, here is one of them.\nRemember that we didn't put an initial amount for H+ since in most cases we ignore the self dissociation of water. Now we will consider that we had pure water, so the initial concentration of H+ is 10^-7 and we want to see how much the HNO2 will dissociate under these conditions so our table becomes\n\n.. .. .. .. .. .. HNO2 <=> H+ + NO2-\nInitial .. .. .. .. 0.5 .. .. .. 10^-7\nDissociate .. ..x\nProduce .. .. .. .. .. .. .. ..x .. .. .x\nAt Equil. .. .. 0.5-x .. 10^-7+x. .x\n\nand Ka=(10^-7+x)x/(0.5-x)\nNow we have to solve the quadratic so we can't do any simplification\n\n0.5Ka-Kax=10^-7x +x^2 =>\nx^2+ (10^-7+Ka)x-0.5Ka=0\n\nThe only acceptable solution is the positive one\nx=0.5(- (10^-7+Ka)+ squareroot (D))\nwhere D=(10^-7+Ka)^2-4*(-0.5Ka)=\n=(10^-7+4*10^-14)^2-4*(-0.5*4*10^-14)\n=9*10^-14\n\nand x=0.5*(-((10^-7))+4*10^-14) +3*10^-7) =10^-7\n\nso now pH=-log(10^-7+x) =-log(2*10^-7) = 6.70
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The distribution of ions across a cell membrane produces a concentration gradient that can be used by the cell to do various kinds of work (i.e. power non-spontaneous reactions).  \n\nFor example, in mitochondria and certain aerobic bacteria, the gradient of H+ ions powers ATP synthase, and allows it to make ATP (an extremely important energy storage molecule).  \n\nIn other cells, the concentration gradients of ions can be used to facilitate active transport across the membrane by coupling an ion moving along it's concentration gradient with another molecule moving against it.\n\nIn neurons, the difference in the concentrations of ions inside and outside the cell creates a membrane polarity that allows the action potential (i.e. the nerve firing) to occur.  When the nerve is activated by a neurotransmitter or a direct external stimulus, sodium channels open, allowing Na+ to rush into the cell, making it positive relative to the external environment.  This change in polarity moves along the cell, and causes the cell to release specific neurotransmitters at the other end.\n\nIf the ions were distributed equally, none of the processes I just mentioned would work!
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Too many to list and explain here, without copying and pasting  --and why should I do all your uni work for you? ;-)\n\nI will recommend a couple of good text books through.  Well worth a purchase or just get them on loan from your library...\n\nAlberts et al, Molecular Biology of the Cell\nStryer, Biochemistry\n\nIt's been since I bought mine.  Think I got editions 2 & 7 back in 1996 and I know both have been updated a couple of times since.  These are still a GREAT basic resourse for this sort of question.
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Water potential is\nψ=ψs+ψp where ψs is the contribution of the solutes (osmotic pressure) and ψp the pressure on that side of the membrane.\n\nψs is always negative, so dissolving solutes lowers the water potential. When there are no cell walls the pressure on both sides of the membrane is the same and thus water potential is equal to ψs.\n\nFor plant or bacterial cells which have walls internal pressure can build up so you have to take it into account if you want to see whether water will enter the cells.
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electrical signals. "An important characteristic of neurons is that they have excitable membranes which allow them to generate and propagate electrical signals." "Membrane potential (or transmembrane potential or transmembrane potential difference or transmembrane potential gradient), is the electrical potential difference (voltage) across a cell's plasma membrane. In membrane biophysics it is sometimes used interchangeably with cell potential, but is applicable to any lipid bilayer or membrane. Hence every organelle and every membranous compartment (such as a synthetic vesicle) has a transmembrane potential (although the size of this potential may be zero)."
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http://www.amasci.com/emotor/statelec.html\n\nhttp://www.phys.unsw.edu.au/PHYS1169/beilby/electric_fields.html\n\nhttp://users.pandora.be/educypedia/electronics/electrostatics.htm
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depolarization which stimulates adjacent Na+ and K+ gates to open, thus starting an action potential in the muscle cell
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Just the usual stuff.  Use an electrolyte (H2SO4/HNO3), a couple of electrodes, a reduction table of half cell potentials, and some electricity.
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Using Google Scholar I found at least one review of osmoregulation in marine mammals: \n\nhttp://jeb.biologists.org/cgi/content/full/204/11/1831\n\nAnd by using a few keywords, many articles come up. Try that :-)
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http://cellbio.utmb.edu/cellbio/nucleus.htm\nhttp://www.cdli.ca/~dpower/cell/nucleus.htm\nhttp://www.cellsalive.com/cells/nucleus.htm\n\nDo some research, we're not here to complete your homework for you.
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I would check out http://www.answers.com/endocrine%20system. This site will give you answers from very reputable sources like Columbia University Press, Houghton Mifflin Company, and others.  It's a good place to start.  You should also check out www.jstor.org.  They have a bunch of full-text articles that have been written.\n\nGood luck!
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None of the available resources are great.  You can use Merck Medicus or WebMD or medicinenet.com or medical-library.org or myelectronicmd.com