Which layer of cervical fascia forms the false capsule of thyroid gland?

Correct Answer: C

Rationale: The correct answer is C: Pretracheal fascia. This layer surrounds the thyroid gland, forming the false capsule. It separates the thyroid from the strap muscles anteriorly and the trachea and esophagus posteriorly. The Carotid sheath (A) encloses the common carotid artery, internal jugular vein, and vagus nerve. The Investing layer (B) covers the sternocleidomastoid and trapezius muscles. The Prevertebral fascia (D) surrounds the vertebral column and deep neck muscles, not directly related to the thyroid gland.

Correct Answer: D

Rationale: The correct answer is D, the anterior pituitary gland, because it secretes TSH, ACTH, and growth hormone. The anterior pituitary gland is also known as the adenohypophysis, and it plays a key role in regulating various bodily functions through the release of different hormones. The other choices are incorrect because the neurohypophysis (choice A) secretes hormones like oxytocin and vasopressin, the pancreas (choice B) secretes insulin and glucagon, and the adrenal medulla (choice C) secretes adrenaline and noradrenaline.

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.

Correct Answer: D

Rationale: Step 1: Cretinism, myxedema, and Graves' disease are all related to thyroid gland function. Step 2: Cretinism is a congenital hypothyroidism, myxedema is adult hypothyroidism, and Graves' disease is hyperthyroidism. Step 3: Thus, they are all disorders of thyroid gland function. Summary: - Choice A is incorrect because they are not all thyroid hormone deficiency diseases. - Choice B is incorrect because they are not all caused by oversecretion of thyroxine. - Choice C is incorrect because they are not primarily related to calcium imbalances due to lack of calcitonin.

Correct Answer: B

Rationale: The correct answer is B: A benign tumor of the adrenal medulla is called a pheochromocytoma. Pheochromocytomas are tumors that arise from the adrenal medulla, leading to overproduction of catecholamines like adrenaline and noradrenaline. This excess secretion can result in symptoms such as high blood pressure, palpitations, and sweating. Choices A and C are incorrect because a benign tumor of the adrenal medulla typically causes high blood pressure, not low blood pressure or Addison's disease. Choice D is incorrect because excess cortisol secretion is associated with conditions like Cushing's syndrome, not pheochromocytoma.