This hormone stimulates osteoclastic activity, causing bone resorption.
- A. Calcitonin
- B. Androgen
- C. PTH
- D. Thyroxine
Correct Answer: C
Rationale: The correct answer is C: PTH. Parathyroid hormone (PTH) stimulates osteoclastic activity, leading to bone resorption. PTH plays a crucial role in regulating calcium levels in the blood. When calcium levels are low, PTH is released to stimulate the release of calcium from bones through osteoclast activity.
A: Calcitonin actually inhibits osteoclastic activity, promoting bone formation.
B: Androgen is a male sex hormone and does not directly influence bone resorption.
D: Thyroxine is a thyroid hormone that regulates metabolism and does not directly affect bone resorption.
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Where does the middle thyroid vein drain?
- A. Brachiocephalic vein
- B. External jugular vein
- C. Internal jugular vein
- D. Subclavian vein
Correct Answer: C
Rationale: The middle thyroid vein drains into the internal jugular vein due to its anatomical location in the neck. The internal jugular vein receives blood from the brain, face, and neck, making it a suitable drainage site for the thyroid gland. The other options (A, B, D) are incorrect because the brachiocephalic vein drains the upper body, the external jugular vein drains the scalp and face, and the subclavian vein drains the upper extremities, none of which are anatomically linked to the thyroid gland.
Enlargement of the thyroid gland:
- A. is called a goiter.
- B. causes Addisonian crisis.
- C. makes a person appear cushingoid.
- D. causes hypocalcemic tetany.
Correct Answer: A
Rationale: Step-by-step rationale for why choice A is correct:
1. Enlargement of the thyroid gland is known as a goiter.
2. A goiter can result from various conditions like iodine deficiency or thyroid disorders.
3. It is a common sign of thyroid dysfunction.
4. Goiter may or may not cause symptoms depending on the underlying cause.
5. Therefore, choice A is the correct answer.
Summary:
- Choice B (Addisonian crisis) is incorrect as it is associated with adrenal insufficiency, not thyroid enlargement.
- Choice C (cushingoid appearance) is incorrect as it is related to excess cortisol production, not thyroid enlargement.
- Choice D (hypocalcemic tetany) is incorrect as it is due to low calcium levels, not thyroid enlargement.
In the pancreas, which are the cells that secrete insulin?
- A. Alpha
- B. Beta
- C. Delta
- D. None
Correct Answer: B
Rationale: The correct answer is B: Beta cells. Beta cells in the pancreas are responsible for secreting insulin. Insulin helps regulate blood sugar levels. Alpha cells (A) secrete glucagon, Delta cells (C) secrete somatostatin, both involved in glucose metabolism, but not insulin secretion. Choice D is incorrect as the pancreas does contain cells that secrete insulin.
Failure of the pituitary to stop producing growth hormone (GH) after body growth is completed results in .
- A. kidney failure
- B. tetany
- C. gigantism
- D. acromegaly
Correct Answer: D
Rationale: The correct answer is D: acromegaly. After body growth is completed, excess GH production can lead to acromegaly, a condition characterized by the enlargement of bones and tissues. This occurs because GH continues to stimulate bone and tissue growth. Kidney failure (A) is not directly related to excess GH production. Tetany (B) is caused by low calcium levels, not excess GH. Gigantism (C) occurs when excess GH is produced during the growth years, leading to abnormal height, not after growth is completed. Therefore, the correct answer is D as it directly correlates with the scenario provided.
Secretion of oxytocin is increased by
- A. milk ejection
- B. dilation of the cervix
- C. increased prolactin levels
- D. increased extracellular fluid (ECF) volume
Correct Answer: B
Rationale: Certainly! The secretion of oxytocin is increased by the dilation of the cervix. When the cervix dilates during childbirth, it triggers the release of oxytocin from the posterior pituitary gland. This hormone plays a crucial role in stimulating uterine contractions during labor and delivery. Milk ejection (choice A) is primarily regulated by oxytocin but does not directly increase its secretion. Increased prolactin levels (choice C) stimulate milk production, not oxytocin secretion. Increased extracellular fluid (ECF) volume (choice D) is not directly related to oxytocin secretion.