An electrolyte is a mineral or salt dissolved in the body. (Write True or False)

Choice A reason: Producing phosphate buffers is not the main function of the kidneys in response to acid-base disturbances. Phosphate buffers are mainly found in the intracellular fluid and the urine, where they help to maintain the pH by binding or releasing hydrogen ions.

Choice B reason: Adjusting PaCO2 levels is not the function of the kidneys, but rather the function of the lungs in response to acid-base disturbances. The lungs regulate the PaCO2 levels by increasing or decreasing the rate and depth of respiration, which affects the amount of carbon dioxide exhaled.

Choice C reason: Producing protein buffers is not the function of the kidneys, but rather the function of the cells and the plasma in response to acid-base disturbances. Protein buffers are the most abundant and versatile buffers in the body, as they can act as acids or bases by donating or accepting hydrogen ions.

Choice D reason: Excreting or reabsorbing hydrogen or bicarbonate is the main function of the kidneys in response to acid-base disturbances. The kidneys regulate the HCO3- levels by either reabsorbing it from the filtrate or generating it from carbon dioxide and water. The kidneys also regulate the hydrogen ion levels by either excreting it into the urine or exchanging it for sodium ions.

An isotonic solution is a solution that has the same osmotic pressure as another solution, which means that the solute concentration on both sides of a semipermeable membrane is equal. This causes no net movement of water across the membrane, and the cells remain the same size and shape. An example of an isotonic solution is normal saline (0.9% sodium chloride), which is used to treat dehydration and fluid loss.