Nokea
If growth hormone is overproduced in the adult, what is the resulting condition called?
- A. pituitary dwarfism
- B. gigantism
- C. acromegaly
- D. myxedema
Correct Answer: C
Rationale: The correct answer is C: acromegaly. In adults, overproduction of growth hormone leads to acromegaly, characterized by enlarged bones and tissues. Pituitary dwarfism (choice A) results from growth hormone deficiency. Gigantism (choice B) occurs when excess growth hormone is produced before epiphyseal plate closure in children. Myxedema (choice D) is associated with hypothyroidism, not growth hormone overproduction. Therefore, choice C is the correct answer as it specifically refers to the condition resulting from excessive growth hormone in adults.
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Selective beta2 stimulants frequently cause:
- A. Skeletal muscle tremors
- B. Tolerance
- C. Tachycardia
- D. All of the above
Correct Answer: D
Rationale: Selective beta2 stimulants typically cause skeletal muscle tremors due to their action on beta2 receptors in skeletal muscles. They can also lead to tolerance with prolonged use, requiring higher doses for the same effect. Additionally, they can cause tachycardia by stimulating beta2 receptors in the heart. Therefore, all of the above choices (A, B, and C) are correct.
Which of the Following Endocrine Glands Contributes to Setting the Body's Biological Clock?
- A. Pituitary gland
- B. Pineal gland
- C. Thymus gland
- D. Adrenal gland
Correct Answer: B
Rationale: The correct answer is B: Pineal gland. The pineal gland secretes melatonin, a hormone that regulates the body's sleep-wake cycle, thus contributing to setting the body's biological clock. This gland responds to light and darkness, helping to synchronize our internal clock with the day-night cycle. The pituitary gland (A) regulates various hormones but not specifically the biological clock. The thymus gland (C) is responsible for immune function, not the biological clock. The adrenal gland (D) secretes hormones related to stress response, not the biological clock. In summary, the pineal gland is key in regulating the body's biological clock through melatonin secretion, making it the correct choice.
Which of the following glands can be classified as an endocrine and exocrine gland?
- A. Thyroid
- B. Thymus
- C. Pancreas
- D. Pituitary
Correct Answer: C
Rationale: The correct answer is C: Pancreas. The pancreas is both an endocrine and exocrine gland. It secretes digestive enzymes (exocrine function) into the small intestine to aid in digestion, and it also releases hormones like insulin and glucagon (endocrine function) into the bloodstream to regulate blood sugar levels.
Rationale:
1. The thyroid gland (choice A) is solely an endocrine gland responsible for producing hormones that regulate metabolism.
2. The thymus gland (choice B) is primarily an endocrine gland involved in immune function, producing hormones that regulate T cell development.
3. The pituitary gland (choice D) is known as the master gland and is purely endocrine, controlling various hormonal functions in the body.
In summary, the pancreas uniquely exhibits both endocrine and exocrine functions, making it the correct choice.
Thyroid hormone (a small iodinated amine) enters target cells in a manner similar to ________.
- A. insulin, because insulin is a small peptide
- B. steroid hormones, because both diffuse easily into target cells
- C. growth hormone, because the thyroid works synergistically with thyroid hormone
- D. glucagon, because the structure of glucagon is similar to that of thyroid hormone
Correct Answer: B
Rationale: The correct answer is B: steroid hormones, because both diffuse easily into target cells. Thyroid hormone, being a small iodinated amine, can easily pass through the cell membrane and bind to intracellular receptors, similar to steroid hormones. Unlike insulin (choice A), which binds to cell surface receptors, thyroid hormone and steroid hormones enter the cell to exert their effects. Growth hormone (choice C) and glucagon (choice D) do not share the same mechanism of entry into target cells as thyroid hormone, making them incorrect choices.
Calcitonin and parathyroid hormone:
- A. are both secreted by the parathyroid glands.
- B. increase plasma levels of calcium.
- C. decrease plasma levels of calcium.
- D. control plasma levels of calcium.
Correct Answer: D
Rationale: Correct Answer: D
Rationale: Calcitonin and parathyroid hormone regulate plasma calcium levels. Calcitonin decreases calcium levels by inhibiting bone breakdown, while parathyroid hormone increases calcium levels by stimulating bone breakdown and increasing calcium reabsorption. Therefore, both hormones work together to maintain calcium homeostasis. The correct answer, choice D, highlights that both hormones control plasma calcium levels.
Summary of Other Choices:
A: Incorrect. Calcitonin is secreted by the thyroid gland, not the parathyroid glands.
B: Incorrect. Calcitonin decreases plasma calcium levels, while parathyroid hormone increases plasma calcium levels.
C: Incorrect. Parathyroid hormone increases plasma calcium levels, whereas calcitonin decreases plasma calcium levels.