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 Very Basic Physiology  

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The Q and A here looks pretty advanced. I am just now starting my second semester of physiology and need all the help I can get. I am a non-traditional student (which means "old," although I was pretty non-traditional when I was young, too), returning to school to get a second degree, that is, one that will actually help me find employment. My first degree was a BFA, which did not require any science to speak of, so everything is brand new to me, making the courses fascinating but daunting.

Am I at too elementary a level for this group?



I am working on the first case study of the year, involving a young, non-compliant type 1 diabetic in a coma. I have concluded he is suffering from ketoacidosis. The question is: what is the cause of his dyspnea, hypotension and tachycardia?

I am guessing that osmotic diuresis has caused a reduction in blood volume and that all three symptoms are the result: the low b/p < low blood volume, the tachycardia and dyspnea result from the lessened oxygen carrying capacity resulting from less blood. Obviously, I'm a little vague. Am I on the right track? If so, is there more? Thanks.


You seem to be on the right track:

As you say hypotension and tachycardia could be related to profound fluid and electrolyte loss.
That dyspnea we call" Kaussmaul respiration" (rapid deep breathing) which decrease CO2 and bicarbonate in extreme circumstances.
Symptoms in DKA will be similar to high anion gap metabolic acidosis.


Thanks, MJL1717,

I was with you, more or less, up until that last sentence. I have no idea what anion gap acidosis is. Like I said, I'm a true newbie. But I'm eager to learn. I appreciate the help.


Hello JohnFMayer,

Anion gap metabolic acidosis is basically adding up all your positive charges and subtracting your negative charges from it...


The texts use only sodium as the major positive charge.

Hope this helps...


sorry a correction its...



It gives you an idea of the unmeasured anions or non chloride acids(lactate, acetoacetate,B-hydroxybutyrate,exogenous toxins etc.) involved in this disorder.


hey,i'm bindu,can u plz explain to me Nernst equation.i'm preparing for usmle step1.


You may not get much clear cut, definitive, to the point response about Nerst unless you read about it in Guyton a few times since the formula is not directly tested on step 1. But Id recommend know and understanding action potntials to the max.


very basic concept tht is necessary to understand regarding nerst eq. is :
this eq. helps in expressing the molar conc. in terms of millivolts!

for eg.,
ICF: 10mM
ECF: 1mM

nerst potential for tht ion will be 60mV


thanx dear.


Id love to know (since Im conscientious) Exactly how many people out of 10 even understood that! :shock:



well! u want to cmpare the forces exretd by the membrane potential and the conc. diff!

units must be the same or how wud u compare! :wink:

so nerst potential comes in handy here and exprsses the conc. diff in terms of mV -same as membrane pot.!

grin grin

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