Nokea
Which mechanism is primarily responsible for maintaining hormone levels within a narrow range?
- A. negative feedback mechanisms
- B. positive feedback mechanisms
- C. hormone-receptor complexes
- D. hormone-gene complexes
Correct Answer: A
Rationale: The correct answer is A: negative feedback mechanisms. Negative feedback mechanisms help maintain hormone levels within a narrow range by inhibiting further hormone production once a certain level is reached. When hormone levels rise, negative feedback signals the body to decrease hormone production, preventing excessive levels. Positive feedback mechanisms, on the other hand, amplify hormone production. Hormone-receptor complexes and hormone-gene complexes are not directly responsible for maintaining hormone levels within a narrow range but rather play roles in hormone signaling and gene expression, respectively.
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Mrs. Crane, an insulin-dependent diabetic, is scheduled for general surgery. The nurse's preoperative teaching should place special emphasis on
- A. pain medications available postoperatively
- B. coughing and deep breathing
- C. early ambulation
- D. adjusting insulin requirements
Correct Answer: D
Rationale: Patients undergoing surgery need adjusted insulin dosages to maintain stable blood glucose levels during the perioperative period.
The second-messenger mechanism of hormone action operates by ________.
- A. synthesizing more of the hormone than is actually needed
- B. increasing the basal metabolic rate in the target organ
- C. not responding to a feedback mechanism
- D. binding to specific receptors and employing the services of G proteins and cAMP
Correct Answer: D
Rationale: The correct answer is D because the second-messenger mechanism involves the hormone binding to specific receptors on the cell surface, activating G proteins, which then trigger the production of cyclic adenosine monophosphate (cAMP) inside the cell. cAMP acts as a secondary messenger to relay the hormone's signal and initiate a cellular response. Synthesizing more hormone than needed (A) is not related to the mechanism. Increasing basal metabolic rate (B) is not a direct result of the second-messenger system. Not responding to feedback (C) contradicts the regulatory nature of hormone actions.
Nervousness, increased body temperature, and increased blood-pressure are indications of _______.
- A. diabetes mellitus
- B. hypoglycemia
- C. hypothyroidism
- D. hyperthyroidism
Correct Answer: D
Rationale: The correct answer is D: hyperthyroidism. Nervousness, increased body temperature, and increased blood pressure are classic symptoms of hyperthyroidism. This condition is characterized by an overactive thyroid gland, leading to an excess production of thyroid hormones. These hormones can cause an increase in metabolism, leading to symptoms such as nervousness, heat intolerance, and elevated heart rate. Diabetes mellitus (A) is not associated with increased body temperature or blood pressure. Hypoglycemia (B) is characterized by low blood sugar levels, leading to symptoms such as dizziness and confusion, not increased body temperature. Hypothyroidism (C) is characterized by an underactive thyroid gland, leading to symptoms such as fatigue, weight gain, and cold intolerance, not increased body temperature or blood pressure.
Thyroxine:
- A. is mostly bound to albumin in the plasma, since this has the largest capacity
- B. is 2-5 times more potent that triiodothyronine (T3)
- C. stimulates TSH release
- D. ∼33% is deiodinated in the liver to T3
Correct Answer: D
Rationale: The correct answer is D. Thyroxine is deiodinated in the liver to T3, so approximately 33% of thyroxine is converted to the more active form, triiodothyronine. This conversion is important for regulating metabolic processes in the body. Choices A and C are incorrect because thyroxine is primarily bound to thyroxine-binding globulin in the plasma, not albumin, and it does not stimulate TSH release. Choice B is incorrect because T3 is actually more potent than thyroxine, not the other way around.
Which of the following hormones does the skin produce?
- A. erythropoietin
- B. melatonin
- C. renin
- D. cholecalciferol
Correct Answer: D
Rationale: The correct answer is D: cholecalciferol. The skin produces cholecalciferol, also known as vitamin D, in response to sunlight exposure. This hormone plays a crucial role in calcium absorption and bone health. Erythropoietin (A) is produced by the kidneys to stimulate red blood cell production. Melatonin (B) is produced by the pineal gland to regulate sleep-wake cycles. Renin (C) is produced by the kidneys to regulate blood pressure. Therefore, the skin does not produce erythropoietin, melatonin, or renin, making them incorrect choices.