The primary target of the releasing and inhibiting hormones of the hypothalamus is the:

Correct Answer: C

Rationale: The correct answer is C. The primary target of releasing and inhibiting hormones from the hypothalamus is the anterior pituitary. The hypothalamus secretes these hormones into the hypophyseal portal system, which directly connects to the anterior pituitary. This interaction controls the release of various hormones from the anterior pituitary, regulating functions such as growth, reproduction, and stress response. Choices A, B, and D are incorrect because releasing and inhibiting hormones from the hypothalamus do not primarily target the liver, adipose tissue, gonads, or bone marrow directly.

Correct Answer: B

Rationale: The correct answer is B: sweat glands. Endocrine glands secrete hormones directly into the bloodstream, affecting various organs and tissues. Sweat glands, on the other hand, are exocrine glands that release sweat through ducts onto the skin's surface to regulate body temperature. Adrenal glands produce hormones like cortisol and adrenaline (A), parathyroid glands regulate calcium levels in the body (C), and the pineal gland produces melatonin to regulate sleep-wake cycles (D). Therefore, sweat glands do not fit the definition of an endocrine gland, making them the correct choice.

Correct Answer: A

Rationale: The correct answer is A: Epinephrine & norepinephrine. These hormones are responsible for the fight-or-flight response. When facing a threat, the adrenal glands release these hormones, which increase heart rate, blood pressure, and energy levels to prepare the body to either fight or flee. Epinephrine and norepinephrine are part of the sympathetic nervous system's response to stress. Choices B, C, and D are incorrect: B: Insulin & glucagon regulate blood sugar levels, not the fight-or-flight response. C: Estrogen & progesterone are reproductive hormones, not involved in the fight-or-flight response. D: Thyroxin & melatonin regulate metabolism and sleep-wake cycles, respectively, not the fight-or-flight response.

Correct Answer: B

Rationale: The correct answer is B: Hormones. The endocrine system consists of ductless glands that secrete hormones directly into the bloodstream to regulate various bodily functions. Hormones are chemical messengers that help control metabolism, growth, development, mood, and other physiological processes. Enzymes (choice A) are not secreted by the endocrine system but by exocrine glands. Electrolytes (choice C) are ions essential for various bodily functions but are not directly secreted by glands of the endocrine system. Choice D, chemicals, is too broad and vague as all substances can be considered chemicals.

Correct Answer: B

Rationale: The correct answer is B. In hyperthyroidism, the thyroid gland produces an excess of thyroid hormones T3 and T4, leading to negative feedback on the pituitary gland, resulting in decreased TSH levels. Therefore, you would expect decreased TSH and increased T3, T4 levels. A is incorrect because TSH would be decreased, not increased. C is incorrect because TSH would be decreased in hyperthyroidism. D is incorrect because T3 and T4 would be increased in hyperthyroidism.