Nervousness, increased body temperature, and increased blood-pressure are indications of _______.

Correct Answer: D

Rationale: The correct answer is D: hyperthyroidism. Nervousness, increased body temperature, and increased blood pressure are classic symptoms of hyperthyroidism. This condition is characterized by an overactive thyroid gland, leading to an excess production of thyroid hormones. These hormones can cause an increase in metabolism, leading to symptoms such as nervousness, heat intolerance, and elevated heart rate. Diabetes mellitus (A) is not associated with increased body temperature or blood pressure. Hypoglycemia (B) is characterized by low blood sugar levels, leading to symptoms such as dizziness and confusion, not increased body temperature. Hypothyroidism (C) is characterized by an underactive thyroid gland, leading to symptoms such as fatigue, weight gain, and cold intolerance, not increased body temperature or blood pressure.

Correct Answer: B

Rationale: The correct answer is B because the hypothalamic-hypophyseal tract is indeed partly contained within the infundibulum, which is a stalk-like structure connecting the hypothalamus to the pituitary gland. This pathway is crucial for the release of hormones from the hypothalamus to the pituitary gland. Choice A is incorrect as the hypophysis and pituitary gland are the same structure. Choice C is incorrect as aldosterone is a hormone produced by the adrenal glands, not related to the hypothalamic-pituitary axis. Choice D is incorrect because prolactin synthesis occurs in the lactotroph cells of the anterior pituitary, not in the hypothalamic-hypophyseal tract.

Correct Answer: D

Rationale: The correct answer is D because the second-messenger mechanism involves the hormone binding to specific receptors on the cell surface, activating G proteins, which then trigger the production of cyclic adenosine monophosphate (cAMP) inside the cell. cAMP acts as a secondary messenger to relay the hormone's signal and initiate a cellular response. Synthesizing more hormone than needed (A) is not related to the mechanism. Increasing basal metabolic rate (B) is not a direct result of the second-messenger system. Not responding to feedback (C) contradicts the regulatory nature of hormone actions.

Correct Answer: C

Rationale: The correct answer is C: An amino acid derivative can be a hormone. This statement is correct because many hormones are derived from amino acids, such as thyroid hormones (derived from tyrosine) and epinephrine (derived from phenylalanine). Hormones can be derived from various sources, including amino acids, peptides, lipids, and even gases. Explanation of other choices: A: Prostaglandins are not biologically active peptides; they are lipid compounds derived from fatty acids. B: Modified cholesterol does not form the main structural component of peptone hormones; peptides are the main structural components of peptide hormones. D: Testosterone is a steroid hormone and not an example of a paracrine, which is a type of chemical messenger that acts on nearby cells.

Correct Answer: D

Rationale: The correct answer is D: excessively high blood iodine concentrations. High blood iodine levels do not inhibit TSH release; they actually stimulate it. Growth hormone-inhibiting hormone (GHIH), rising levels of glucocorticoids, and somatostatin are all factors that inhibit TSH release. GHIH inhibits TSH release by acting on the pituitary gland. Glucocorticoids have a negative feedback effect on the hypothalamus and pituitary gland, reducing TSH release. Somatostatin inhibits the release of various hormones, including TSH.