Nokea
X is a drug that contains a mixture of amphetamines. It is used for managing Attention-Deficit/Hyperactivity disorder (ADHD). The drug causes autonomic effects that can be fatal if an overdose is taken. How does X work in the body?
- A. Blocks muscarinic receptors, causing what is basically 'atropine poisoning'
- B. Blocks β2 receptors on airway smooth muscle, causing bronchoconstriction
- C. Inhibits MAO, leading to a 'shut-down' of the sympathetic nervous system
- D. Releases neuronal noradrenaline, causing excessive sympathetic effects, e.g., severe rises of blood pressure
Correct Answer: D
Rationale: The correct answer is D because X, a mixture of amphetamines, works by releasing neuronal noradrenaline, causing excessive sympathetic effects like severe rises in blood pressure. This is how the drug helps manage ADHD symptoms. The other choices are incorrect because A (blocking muscarinic receptors) would not be related to the autonomic effects seen with X, B (blocking β2 receptors) would not explain the fatal autonomic effects, and C (inhibiting MAO) would not lead to the described autonomic effects. Therefore, D is the correct choice based on how X works in the body to produce its effects on the sympathetic nervous system.
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What is the definition of a gene?
- A. all the DNA in a cell that controls metabolic reactions
- B. a length of DNA that codes for a protein
- C. the nucleus and its chromosomes
- D. all the DNA in a cell that determines the inheritance of sex
Correct Answer: B
Rationale: The correct answer is B: a length of DNA that codes for a protein. Genes are specific sequences of DNA that encode instructions for building proteins. This is the fundamental role of genes in the process of protein synthesis. Choice A is incorrect because not all DNA in a cell controls metabolic reactions; some DNA is non-coding. Choice C is incorrect as it refers to the entire nucleus and its contents, not just the gene. Choice D is incorrect as genes do not solely determine the inheritance of sex; they also code for other traits. In summary, the definition of a gene as a segment of DNA that codes for a protein aligns with the known function and role of genes in genetics and molecular biology.
Which of the following is the response to low plasma levels of calcium?
- A. Secretion of calcitonin
- B. Secretion of the beta cells of the islets of Langerhans
- C. Inhibition of the adenohypophyseal release of ACTH
- D. Secretion of PTH
Correct Answer: D
Rationale: The correct answer is D: Secretion of PTH. Low plasma levels of calcium trigger the parathyroid glands to release parathyroid hormone (PTH) to increase calcium levels. PTH acts on the bones to stimulate calcium release, on the kidneys to increase calcium reabsorption, and on the intestines to enhance absorption.
A: Secretion of calcitonin is incorrect because calcitonin is released in response to high calcium levels to lower them.
B: Secretion of the beta cells of the islets of Langerhans is incorrect as these cells secrete insulin in response to high blood glucose levels.
C: Inhibition of the adenohypophyseal release of ACTH is incorrect as ACTH is related to stress response, not calcium regulation.
Cushing syndrome:
- A. may be caused by steroid (prednisone) therapy.
- B. is caused by adrenal insufficiency.
- C. is characterized by hypoglycemia and low blood volume.
- D. is treated with growth hormone.
Correct Answer: A
Rationale: The correct answer is A because Cushing syndrome is typically caused by prolonged exposure to high levels of cortisol, which can result from steroid therapy like prednisone. This leads to symptoms such as weight gain, high blood pressure, and muscle weakness. Adrenal insufficiency (B) is actually the opposite condition. Cushing syndrome is characterized by hyperglycemia and increased blood volume, making choices C incorrect. Growth hormone is not a primary treatment for Cushing syndrome, making choice D incorrect.
What stimulates the release of PTH from the parathyroid gland?
- A. TSH from the posterior pituitary gland
- B. high levels of calcium in the blood
- C. calcitonin from the anterior pituitary gland
- D. low levels of calcium in the blood
Correct Answer: D
Rationale: The correct answer is D: low levels of calcium in the blood. When calcium levels drop, the parathyroid gland releases parathyroid hormone (PTH) to increase calcium levels in the blood. This is a negative feedback mechanism to maintain calcium homeostasis. A: TSH from the posterior pituitary gland is incorrect because TSH is involved in regulating thyroid function, not PTH release. B: High levels of calcium in the blood would not stimulate PTH release as the body aims to lower, not raise, calcium levels. C: Calcitonin from the anterior pituitary gland is incorrect because calcitonin is released by the thyroid gland and works to lower blood calcium levels, opposing the action of PTH.
To prevent hyperglycemia or hypoglycemia related to exercise, what should the nurse teach the patient using glucose-lowering agents about the best time for exercise?
- A. Only after a 15-g carbohydrate snack is eaten
- B. About 1 hour after eating when blood glucose levels are rising
- C. When glucose monitoring reveals that the blood glucose is in the normal range
- D. When blood glucose levels are high, because exercise always has a hypoglycemic effect
Correct Answer: B
Rationale: Exercising about 1 hour after eating helps to ensure blood glucose is rising and reduces the risk of hypoglycemia.