▸ State the normal balance and distribution the potassium in between cells and extracellular fluid.

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▸ describe how potassium moves between cells and also the extracellular fluid, and also how, ~ above a short-term basis, the activity protects the extracellular fluid from huge changes in potassium concentration.

▸ State why plasma level of potassium execute not always reflect the status of total-body potassium.

▸ State exactly how insulin and also epinephrine influence the cellular uptake of potassium and also identify the situations in which these hormonal influences are most important.

▸ State the relative quantities of potassium reabsorbed by the proximal tubule and thick ascending body of Henle\"s loop nevertheless of the state that potassium intake.

▸ define how nephron segments beyond the special ascending limb deserve to manifest net secretion or reabsorption; define the role of principal cells and also intercalated cell in these processes.

▸ list inputs that control the price of potassium secretion by the distal nephron.

▸ describe the actions of ROMK and BK potassium networks in problems of low, normal, and high potassium excretion.

▸ describe how alters in plasma potassium influence aldosterone secretion.

▸ State the effects of most diuretic drugs on potassium excretion.

The vast bulk of human body potassium is freely liquified in the cytosol of organization cells and also constitutes the major osmotic component of the intracellular liquid (ICF). Only around 2% of total-body potassium is in the extracellular fluid (ECF). This small fraction, however, is absolutely an important for human body function, and the concentration the potassium in the ECF is a carefully regulated quantity. Major increases and decreases (called hyperkalemia and also hypokalemia) in plasma values are reason for medical intervention. The importance of maintaining this concentration stems primarily from the role of potassium in the excitability of nerve and also muscle, especially the heart. The proportion of the intracellular come extracellular concentration that potassium is the major determinant of the resting membrane potential in this cells. A far-reaching rise in the extracellular potassium concentration reasons a continual depolarization. Short extracellular potassium may hyperpolarize or depolarize depending upon how changes in extracellular potassium affect membrane permeability. Both conditions lead come muscle and also cardiac disturbances.


The vast bulk of human body potassium is included in organization cells; only about 2% is in the ECF.

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Given the the vast bulk of body potassium is included within cells, the extracellular potassium concentration is crucially dependency on (1) the total amount the potassium in the body and also (2) the distribution of this potassium between the extracellular and also intracellular fluid compartments. Total-body potassium is figured out by the balance in between potassium intake and excretion. Healthy individuals continue to be in potassium balance, together they do in salt balance, through excreting potassium in an answer to dietary loads and withholding excretion as soon as body potassium is depleted. The pee is the major route that potassium excretion, although part is lost in the ...