Selective β2 agonists produce all of the following EXCEPT:
- A. Stimulate β2 > β1
- B. Bronchodilation
- C. Decrease of blood pressure
- D. Stimulate uterine contraction
Correct Answer: D
Rationale: The correct answer is D: Stimulate uterine contraction. Selective β2 agonists primarily target β2 receptors in the lungs, leading to bronchodilation. They have minimal effect on β1 receptors, thus do not significantly impact heart rate or blood pressure. However, β2 receptors in the uterus can cause uterine relaxation, not contraction. Therefore, selective β2 agonists do not stimulate uterine contractions. Choices A, B, and C are incorrect as they align with the typical effects of selective β2 agonists.
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Which class of oral glucose-lowering agents is most commonly used for people with type 2 diabetes because it reduces hepatic glucose production and enhances tissue uptake of glucose?
- A. Insulin
- B. Meglitinide
- C. Biguanide
- D. Sulfonylurea
Correct Answer: B
Rationale: Biguanides, like metformin, are commonly used because they reduce glucose production in the liver and enhance tissue glucose uptake.
What is meant by antibiotic resistance?
- A. No bacteria will be killed by any antibiotic.
- B. Only some bacteria will be killed by some antibiotics.
- C. No viruses will be killed by any antibiotic.
- D. Only some viruses will be killed by some antibiotics.
Correct Answer: B
Rationale: The correct answer is B: Only some bacteria will be killed by some antibiotics. Antibiotic resistance refers to the ability of bacteria to survive and grow despite the presence of an antibiotic. This occurs when bacteria evolve and develop mechanisms to defend against antibiotics. It is not accurate to say that no bacteria will be killed by any antibiotic (choice A) as some bacteria may still be susceptible to certain antibiotics. Antibiotics are not effective against viruses, so choice C and D are incorrect. In summary, antibiotic resistance specifically pertains to bacteria developing the ability to survive some antibiotics, making choice B the correct answer.
Regarding carbohydrate metabolism:
- A. glucokinase is increased in starvation
- B. the breakdown of glycogen is called glycolysis
- C. the direct oxidative pathway involves the breakdown of glucose through triose
- D. the conversion of pyruvate to acetyl-CoA is irreversible
Correct Answer: D
Rationale: Correct Answer: D - The conversion of pyruvate to acetyl-CoA is irreversible because it is catalyzed by the enzyme pyruvate dehydrogenase. This step is a key regulatory point in carbohydrate metabolism as it commits pyruvate to enter the citric acid cycle for further energy production. Reversing this step would disrupt the normal flow of metabolic pathways.
Summary of other choices:
A: Glucokinase is not increased in starvation; it regulates glucose uptake in the liver.
B: The breakdown of glycogen is called glycogenolysis, not glycolysis which is the breakdown of glucose.
C: The direct oxidative pathway involves the breakdown of glucose through glycolysis, not triose.
What accurately demonstrates that hormones of one gland influence the function of hormones of another gland?
- A. Increased insulin levels inhibit the secretion of glucagon.
- B. Increased cortisol levels stimulate the secretion of insulin.
- C. Increased testosterone levels inhibit the release of estrogen.
- D. Increased atrial natriuretic peptide (ANP) levels inhibit the secretion of aldosterone.
Correct Answer: A
Rationale: Increased insulin levels inhibit the secretion of glucagon, demonstrating the interaction between these hormones in maintaining glucose balance.
A hormone that suppresses gluconeogenesis:
- A. increases the renal excretion of sodium and water.
- B. prevents hyperglycemia.
- C. causes diuresis.
- D. causes hypocalcemia.
Correct Answer: B
Rationale: The correct answer is B because a hormone that suppresses gluconeogenesis helps to prevent hyperglycemia by inhibiting the production of glucose in the liver. This hormone regulates blood sugar levels by reducing the formation of new glucose molecules.
Choice A is incorrect because increasing renal excretion of sodium and water is related to the regulation of fluid balance, not gluconeogenesis. Choice C is incorrect because causing diuresis involves increasing urine production and is not directly related to suppressing gluconeogenesis. Choice D is incorrect because causing hypocalcemia refers to low levels of calcium in the blood and is not associated with the suppression of gluconeogenesis.