Albuterol causes selective activation of β2 adrenergic receptors when administered in 'low doses,' mainly by inhalation. If very large doses of albuterol were given, or if the drug is administered intravenously, the effects caused by albuterol would look quite different and would resemble those of which one of the following drugs?

Correct Answer: B

Rationale: Step 1: Albuterol selectively activates β2 adrenergic receptors in low doses. Step 2: Isoprenaline is a non-selective beta-adrenergic agonist. Step 3: Very large doses of albuterol or IV administration would lead to non-selective activation of beta receptors. Step 4: Isoprenaline also activates both β1 and β2 receptors, causing a broad range of effects. Step 5: Therefore, the effects of high-dose albuterol would resemble those of Isoprenaline, making B the correct answer. Summary: Choice A (Epinephrine) is incorrect because epinephrine primarily acts on both α and β adrenergic receptors, not just β2. Choice C (Norepinephrine) is incorrect as it mainly acts on α adrenergic receptors, not β. Choice D (Phenylephrine) is incorrect because it is a

Correct Answer: B

Rationale: To find the mass of hydrogen chloride that reacts with 5.1g of ammonia, we need to use the stoichiometry of the balanced chemical equation. The balanced equation for the reaction between ammonia (NH3) and hydrogen chloride (HCl) is: NH3 + HCl → NH4Cl From the equation, we can see that 1 mole of NH3 reacts with 1 mole of HCl to form 1 mole of NH4Cl. Therefore, the molar ratio of NH3 to HCl is 1:1. First, we need to convert the given mass of ammonia (5.1g) to moles using the molar mass of ammonia (17g/mol): 5.1g NH3 * (1 mol NH3 / 17g NH3) = 0.3 mol NH3 Since the molar ratio of NH3 to HCl is 1:1, the moles of HCl that react with

Correct Answer: C

Rationale: The correct equation for calculating power is P = ΔE / t. Power is defined as the rate at which work is done or energy is transferred. In this equation, ΔE represents the change in energy and t represents the time taken for that change. Dividing the change in energy by the time gives us the power. This equation aligns with the fundamental definition of power. Choice A (P = ΔE × t) is incorrect because it implies that power is directly proportional to both the change in energy and time, which is not always the case. Choice B (P = W × t) is incorrect because it incorrectly uses work (W) in the equation for power, while power is specifically related to the rate at which work is done, not the work itself. Choice D (P = W / ΔE) is incorrect because it suggests power is inversely proportional to the change in energy, which is not a characteristic of power.

Correct Answer: B

Rationale: The correct answer is B: humoral stimuli. Parathyroid hormone secretion is regulated by the concentration of calcium in the blood, which is an example of humoral stimuli. When blood calcium levels decrease, parathyroid hormone is released to increase calcium levels. Pituitary gland stimuli (A), neural stimuli (C), and hormonal stimuli (D) are not directly involved in the regulation of parathyroid hormone secretion.

Correct Answer: A

Rationale: The correct answer is A: nervous system. The nervous system can directly override normal endocrine controls through the release of neurotransmitters that can stimulate or inhibit hormone release from endocrine glands. The nervous system can rapidly respond to immediate changes in the internal or external environment, allowing for quick adjustments in hormone levels. Summary of why the other choices are incorrect: B: The circulatory system is not involved in directly overriding endocrine controls. C: The digestive system primarily regulates the breakdown and absorption of nutrients, not endocrine controls. D: The reproductive system is responsible for the production of sex hormones and gametes, but it does not directly override normal endocrine controls.