Nokea
Insufficient Levels of Thyroid Hormone in Adults Cause-------------
- A. Goiter
- B. Tetany
- C. Myxedema
- D. Cretinism
Correct Answer: C
Rationale: The correct answer is C: Myxedema. Insufficient levels of thyroid hormone in adults lead to myxedema due to decreased metabolism and energy production. Goiter (A) is the enlargement of the thyroid gland, not caused by low thyroid hormone levels. Tetany (B) is muscle spasms due to low calcium levels, not related to thyroid hormone deficiency. Cretinism (D) is a condition of severe hypothyroidism in infants, not in adults. Therefore, the correct choice is C as it directly relates to the consequences of low thyroid hormone levels in adults.
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Steroid hormones function by binding to receptor proteins within the ________. Once the hormone binds to a receptor, it activates ______.
- A. nucleus: a second messenger
- B. nucleus: particular genes
- C. plasma membrane: a second messenger
- D. plasma membrane: particular genes
Correct Answer: B
Rationale: The correct answer is B because steroid hormones bind to receptor proteins in the nucleus, forming a hormone-receptor complex that directly influences the expression of specific genes. This process leads to the activation or repression of particular genes, resulting in changes in cellular functions. Choices A and C are incorrect because steroid hormones do not bind to receptors in the plasma membrane or use second messengers for signal transduction. Choice D is incorrect as steroid hormones do not directly regulate genes at the plasma membrane level.
When the patient with parathyroid disease experiences symptoms of hypocalcemia, what is a measure that can be used to temporarily raise serum calcium levels?
- A. Administer IV normal saline.
- B. Administer furosemide (Lasix) as ordered.
- C. Have patient rebreathe in a paper bag.
- D. Administer oral phosphorus supplements.
Correct Answer: A
Rationale: IV normal saline is often used in hypocalcemia to increase serum calcium levels by improving renal calcium reabsorption.
Iodination of thyroid hormones is mediated by __________.
- A. lysosomes in the cell
- B. the Golgi apparatus
- C. colloid endocytosis
- D. peroxidase enzymes
Correct Answer: D
Rationale: The correct answer is D: peroxidase enzymes. Peroxidase enzymes are responsible for catalyzing the iodination process of thyroid hormones in the thyroid gland. They facilitate the incorporation of iodine atoms into tyrosine residues within thyroglobulin to form thyroid hormones T3 and T4. Lysosomes (choice A) are involved in cellular waste disposal, not iodination. The Golgi apparatus (choice B) is responsible for processing and packaging proteins, not iodination. Colloid endocytosis (choice C) is the process of internalizing colloid-containing vesicles in thyroid follicular cells, but it is not directly involved in iodination.
The release of oxytocin is controlled by _____ feedback.
- A. negative
- B. neutral
- C. positive
Correct Answer: C
Rationale: The correct answer is C: positive feedback. Oxytocin release is triggered by the positive feedback mechanism. When oxytocin is released in response to a stimulus, it further stimulates the release of more oxytocin, intensifying the effect. This continuous loop enhances the initial response, leading to a cascade effect. Negative feedback (choice A) works to maintain homeostasis by counteracting the initial stimulus, which is not the case for oxytocin release. Neutral feedback (choice B) does not play a significant role in regulating hormone release. Choice D is incomplete and irrelevant.
Which is NOT an action of CCK?
- A. gallbladder contraction
- B. increased gastric motility and emptying
- C. glucagon secretion
- D. secretion of pancreatic juice
Correct Answer: B
Rationale: The correct answer is B: increased gastric motility and emptying. Cholecystokinin (CCK) is a hormone that primarily functions to stimulate gallbladder contraction (A), secretion of pancreatic juice (D), and inhibit gastric motility and emptying. Choice C, glucagon secretion, is not directly related to the actions of CCK. The incorrect choices (A, C, D) are all actions associated with CCK, while choice B goes against the typical action of CCK on gastric motility.