The transcription of new messenger RNA is a function of __________.

Correct Answer: B

Rationale: The correct answer is B: steroid hormones. Steroid hormones are known to regulate gene expression by binding to specific receptors and influencing transcription processes. They can directly affect the transcription of new messenger RNA in the cell. Pancreatic hormones (A), catecholamines (C), and pituitary gland hormones (D) are not directly involved in the transcription of new messenger RNA. Pancreatic hormones primarily regulate blood sugar levels, catecholamines are involved in the fight-or-flight response, and pituitary gland hormones regulate various functions such as growth, reproduction, and metabolism.

Correct Answer: A

Rationale: Step 1: The pituitary gland is located in the sella turcica of the sphenoid bone. Step 2: The cavernous sinus is a venous sinus located on each side of the sella turcica. Step 3: The pituitary gland lies laterally to the cavernous sinus. Step 4: Therefore, the correct answer is A: The cavernous sinus. Summary: B is incorrect as the hypothalamus is superior to the pituitary gland. C is incorrect as the diaphragma sellae is a part of the dura mater covering the pituitary gland. D is incorrect as the optic chiasma is located superior to the pituitary gland.

Correct Answer: b

Rationale: The correct answer is B: Adrenocorticotropic hormone (ACTH). ACTH is produced by the anterior lobe of the pituitary gland and stimulates the adrenal cortex to secrete cortisol. Inhibin is produced in the ovaries and testes, not the pituitary gland. Triiodothyronine is a thyroid hormone produced by the thyroid gland, not the pituitary gland. Oxytocin is produced by the posterior lobe of the pituitary gland, not the anterior lobe. Therefore, the correct answer is B because it is the hormone that originates from the anterior lobe of the pituitary gland.

Correct Answer: B

Rationale: The correct answer is B because steroids include glucocorticoids, mineralocorticoids, and androgens, which are hormones secreted by the adrenal cortex. Glucocorticoids regulate metabolism and immune response, mineralocorticoids regulate electrolyte balance, and androgens are male sex hormones. Choice A is incorrect because steroids are secreted by the adrenal cortex, not the adrenal medulla. Choice C is incorrect because steroids act by entering the target cells and binding to intracellular receptors, not by stimulating second messengers like cAMP. Choice D is incorrect because steroids are not secreted by the pancreas; instead, the pancreas secretes hormones like insulin and glucagon.

Correct Answer: D

Rationale: Rationale for Correct Answer D: Catecholamines include epinephrine and norepinephrine. These hormones are produced by the adrenal medulla in response to stress and play a crucial role in the fight-or-flight response. Epinephrine increases heart rate and blood flow to muscles, while norepinephrine helps maintain blood pressure. These actions help the body respond to stressful situations. Summary of Other Choices: A: Incorrect. Cortisol, aldosterone, and testosterone are not catecholamines. They are steroid hormones produced by the adrenal cortex. B: Incorrect. Adrenal cortex secretes cortisol and aldosterone, not catecholamines. C: Incorrect. Catecholamines actually increase plasma glucose levels to provide energy during stress.