All but one of the following compounds releases large amounts of energy on breakdown:
- A. cAMP
- B. ATP
- C. creatine phosphate
- D. ADP
Correct Answer: A
Rationale: The correct answer is A: cAMP. cAMP, or cyclic adenosine monophosphate, does not release large amounts of energy on breakdown compared to the other choices. Here's the rationale:
1. ATP (Choice B) is known as the energy currency of the cell and releases a significant amount of energy when broken down.
2. Creatine phosphate (Choice C) is a high-energy compound that can rapidly donate its phosphate group to regenerate ATP.
3. ADP (Choice D) releases energy when converted to ATP through phosphorylation.
4. cAMP (Choice A) is a secondary messenger involved in signal transduction and does not store or release energy like ATP or creatine phosphate.
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The rate of metabolism of all body cells is regulated by _______.
- A. parathyroid hormone
- B. aldosterone
- C. calcitonin
- D. thyroid hormone
Correct Answer: D
Rationale: The correct answer is D: thyroid hormone. Thyroid hormone plays a crucial role in regulating the rate of metabolism in all body cells by influencing the production of enzymes involved in energy production. It increases the body's metabolic rate, affecting processes such as heart rate, temperature regulation, and energy expenditure. Parathyroid hormone (A) regulates calcium levels, aldosterone (B) regulates electrolyte balance, and calcitonin (C) regulates calcium metabolism, but they do not directly influence overall metabolism rate in all body cells. Thyroid hormone is the primary hormone responsible for controlling metabolism throughout the body.
What is a cause of primary hypothyroidism in adults?
- A. Malignant or benign thyroid nodules
- B. Surgical removal or failure of the pituitary gland
- C. Surgical removal or radiation of the thyroid gland
- D. Autoimmune-induced atrophy of the thyroid gland
Correct Answer: D
Rationale: Primary hypothyroidism in adults is commonly caused by autoimmune diseases such as Hashimoto's thyroiditis, which leads to thyroid tissue destruction.
The binding of a steroid hormone to its receptor would lead to the __________.
- A. transcription of the DNA for the gene that is 'turned on' by this event
- B. direct activation of second-messenger agents in the cell
- C. direct activation of enzymes in the cell
- D. formation of cAMP
Correct Answer: A
Rationale: The correct answer is A because the binding of a steroid hormone to its receptor triggers a series of events that ultimately lead to the transcription of DNA for the gene that is 'turned on'. This process involves the hormone-receptor complex entering the nucleus, binding to specific DNA sequences, recruiting transcription factors, and initiating gene expression.
Choice B is incorrect because steroid hormones do not typically use second messengers for signaling. Choice C is incorrect because while some hormones can activate enzymes indirectly, steroid hormones primarily act through gene transcription. Choice D is incorrect because cAMP is typically associated with signaling pathways involving non-steroid hormones like adrenaline.
A patient has a low serum T3 level. The health care provider orders measurement of the TSH level. If the TSH level is elevated, what does this indicate?
- A. The cause of the low T3 level is most likely primary hypothyroidism.
- B. The negative feedback system is failing to stimulate the anterior pituitary gland.
- C. The patient has an underactive thyroid gland that is not receiving TSH stimulation.
- D. Most likely there is a tumor on the anterior pituitary gland that is causing increased production of TSH.
Correct Answer: A
Rationale: Elevated TSH levels indicate that the thyroid gland is underactive and is not producing enough T3 and T4, characteristic of primary hypothyroidism.
During care of the patient with SIADH, what should the nurse do?
- A. Monitor neurologic status at least every 2 hours.
- B. Teach the patient receiving treatment with diuretics to restrict sodium intake.
- C. Keep the head of the bed elevated to prevent antidiuretic hormone (ADH) release.
- D. Notify the health care provider if the patient's blood pressure decreases more than 20 mm Hg from baseline.
Correct Answer: A
Rationale: Frequent neurologic monitoring is essential for patients with SIADH due to the risk of cerebral edema from hyponatremia.