Lena Mason, who has diabetes, is admitted in a stuporous condition. Her blood gases show a pH of 7.33, PaCO2 of 40 mm Hg, and HCO3- of 20 mEq/L. What type of acid-base imbalance does this patient have?

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.

Choice A reason: One slice of wheat bread is not the best source of potassium, as it contains only about 70 mg of potassium per serving. The recommended daily intake of potassium for adults is 4,700 mg.

Choice B reason: One wedge of cantaloupe is a good source of potassium, as it contains about 430 mg of potassium per serving. However, it is not the best source of potassium among the choices given.

Choice C reason: One banana is the best source of potassium among the choices given, as it contains about 420 mg of potassium per serving. Bananas are also rich in fiber, vitamin C, and antioxidants.

Choice D reason: One slice of cheddar cheese is not the best source of potassium, as it contains only about 28 mg of potassium per serving. Cheese is also high in sodium, fat, and calories, which can have negative effects on blood pressure and cholesterol levels.