Which statement is correct regarding beta receptors?

Choice A Reason:

An increase in HCO3- (bicarbonate) is not typically associated with diarrhea and lower intestinal fluid losses. In fact, the opposite is true. Diarrhea often leads to a loss of bicarbonate, which can result in metabolic acidosis. Therefore, this choice is incorrect.

Choice B Reason:

This is the correct answer. Diarrhea and other lower intestinal fluid losses lead to a decrease in HCO3- levels. The loss of bicarbonate from the body results in a lower pH, contributing to metabolic acidosis. This condition occurs because bicarbonate is a key buffer that helps maintain the acid-base balance in the blood.

Choice C Reason:

An increase in the chance of alkalosis is not typically associated with diarrhea. Alkalosis refers to a condition where the pH of the blood is higher than normal, which can occur due to a loss of hydrogen ions or an increase in bicarbonate. However, diarrhea usually causes a loss of bicarbonate, leading to acidosis rather than alkalosis.

Choice D Reason:

Saying that diarrhea has no effect on the pH of the blood is incorrect. Diarrhea can significantly impact the acid-base balance in the body by causing a loss of bicarbonate, leading to metabolic acidosis. Therefore, this choice is incorrect.

Choice A Reason:

To determine how much of the medication remains in the body after a certain period, we need to understand the concept of half-life. The half-life of a medication is the time it takes for the concentration of the drug in the bloodstream to reduce by half. For Medication A, the half-life is 3 hours. After 12 hours, which is four half-lives, the amount of medication remaining can be calculated step by step.

Choice B Reason:

Let’s break down the calculation. Initially, the patient receives 400 mg of Medication A. After the first half-life (3 hours), the amount of medication remaining is 400 mg ÷ 2 = 200 mg. After the second half-life (6 hours), the amount remaining is 200 mg ÷ 2 = 100 mg. After the third half-life (9 hours), the amount remaining is 100 mg ÷ 2 = 50 mg. Finally, after the fourth half-life (12 hours), the amount remaining is 50 mg ÷ 2 = 25 mg. Therefore, 375 mg is not a correct answer.

Choice C Reason:

Similarly, 150 mg is not correct. As shown in the detailed calculation, the amount of medication decreases by half every 3 hours. After 12 hours, the remaining amount is 25 mg, not 150 mg. This choice does not align with the half-life calculation.

Choice D Reason:

This is the correct answer. The step-by-step calculation shows that after 12 hours, which is equivalent to four half-lives, the amount of Medication A remaining in the patient’s body is 25 mg. This demonstrates the principle of half-life and how the concentration of a drug decreases over time.