Steroid hormones:

Correct Answer: B

Rationale: The correct answer is B: Steroid hormones are secreted by the adrenal cortex. The adrenal cortex is responsible for producing steroid hormones such as cortisol, aldosterone, and sex hormones. This is supported by the understanding of endocrine gland functions. Choices A, C, and D are incorrect because steroid hormones do not require a second messenger, are not secreted by the posterior pituitary, and are not secreted by the pancreas. Understanding the specific glands and their hormone production is crucial in selecting the correct answer.

Correct Answer: D

Rationale: The correct answer is D: Pituitary gland. The pituitary gland is known as the master gland because it controls the functions of other endocrine glands in the body by secreting various hormones that regulate growth, reproduction, metabolism, and other essential bodily functions. It is located at the base of the brain and plays a crucial role in maintaining hormonal balance. Explanation for other choices: A: Adrenal gland primarily regulates stress response and metabolism. B: Liver is not an endocrine gland; it is involved in metabolism and detoxification. C: Pancreas is responsible for regulating blood sugar levels through insulin and glucagon secretion but is not known as the master gland.

Correct Answer: C

Rationale: The correct answer is C: Glucagon. Glucagon stimulates gluconeogenesis in the liver by promoting the breakdown of glycogen stores into glucose. Insulin, choice A, actually inhibits gluconeogenesis by promoting glucose uptake and storage. Growth hormone, choice B, primarily affects protein synthesis and growth rather than directly stimulating gluconeogenesis. Estrogen, choice D, is not directly involved in regulating gluconeogenesis in the liver. Therefore, based on its specific function in promoting glucose production in the liver, glucagon is the correct answer.

Correct Answer: B

Rationale: Prolactin is the correct answer because it is the hormone responsible for milk production in the mammary glands. It is secreted by the pituitary gland in response to the suckling stimulus from the baby. Prolactin stimulates the alveoli in the mammary glands to produce milk. Somatotropin (A), luteinizing hormone (C), and follicle-stimulating hormone (D) do not play a direct role in milk production. Somatotropin is involved in growth, luteinizing hormone is involved in ovulation, and follicle-stimulating hormone is involved in the development of ovarian follicles.

Correct Answer: D

Rationale: Rationale: The parafollicular cells in the tissue sample indicate a tumor of the thyroid gland, likely medullary thyroid carcinoma (MTC) associated with Multiple Endocrine Neoplasia Type II (MEN II). MTC primarily secretes calcitonin. Monitoring Calcitonin levels is crucial for assessing disease progression and treatment response in MTC. Measuring Thyroid Hormone Levels (A) would not be specific for MTC. Iodine Levels (B) are not relevant in this context. TSH Levels (C) reflect pituitary feedback and are not specific to MTC. Therefore, the best way to monitor treatment in this case is to measure Calcitonin Levels (D).