Final answer:
The claim that potassium loss is rarely a problem due to efficient absorption by the kidneys is false because kidney function involves a complex balance of filtration, reabsorption, and secretion influenced by hormones and various health conditions.
Step-by-step explanation:
The statement that potassium loss is rarely a problem because it is so well absorbed by the kidney is false.
While potassium is indeed mostly absorbed in the gastrointestinal tract, with less than 10% eliminated in the feces, the regulation of potassium levels is a more complex process involving the kidneys’ ability to filter, reabsorb, and secrete potassium.
In the kidneys, sodium is reabsorbed and potassium is excreted in the collecting tubules, primarily controlled by hormones such as aldosterone and angiotensin II. These hormones influence the amount of sodium and potassium that is either reabsorbed or secreted.
Moreover, factors like acid-base balance, adrenal cortex function, and overall kidney health impact potassium excretion. In cases of impaired kidney function or conditions causing abnormal potassium loss, such as diarrhea, significant potassium loss can occur, leading to potential health risks like hypokalemia.