Which of the following has both endocrine and exocrine functions?

Correct Answer: D

Rationale: The correct answer is D: pancreas. The pancreas has both endocrine (produces hormones like insulin and glucagon) and exocrine (produces digestive enzymes) functions. This dual role makes it unique among the other options. The anterior pituitary (A) is purely endocrine, producing hormones like growth hormone. The thyroid (B) primarily functions as an endocrine gland, producing hormones like thyroxine. The adrenal medulla (C) is also solely endocrine, secreting hormones like epinephrine and norepinephrine. Therefore, the pancreas is the only organ among the choices that performs both endocrine and exocrine functions.

Correct Answer: D

Rationale: The correct answer is D: direct control of the nervous system. Hormonal stimuli typically target specific cells or tissues to elicit a response, such as changes in membrane potential, genetic events leading to protein synthesis, or an increase in enzymatic activity. Hormones do not directly control the nervous system, as the nervous system operates independently and responds to its own set of stimuli. Therefore, D is the correct answer as it does not align with the typical effects of hormonal stimulation. Choices A, B, and C are incorrect as they are all changes that can be caused by hormonal stimuli.

Correct Answer: A

Rationale: The correct answer is A: the heart. Atrial Natriuretic Peptide (ANP) is synthesized and released by the atrial cells of the heart in response to stretching of the atrial wall due to increased blood volume or pressure. ANP functions to regulate blood pressure and fluid balance by promoting natriuresis and vasodilation. The kidney (choice B) is responsible for filtering blood and regulating electrolyte balance, but it does not synthesize ANP. The skin (choice C) is involved in thermoregulation and vitamin D synthesis, not ANP production. The spleen (choice D) plays a role in immune function and blood storage, but it does not synthesize ANP.

Correct Answer: C

Rationale: The correct answer is C: liver. The liver does not produce hormones. Hormones are primarily produced by endocrine glands such as the pituitary, thyroid, adrenal glands, etc. The liver's main functions are related to metabolism, detoxification, and storage, rather than hormone production. The heart (choice A) produces hormones like atrial natriuretic peptide. The kidney (choice B) produces hormones like erythropoietin and renin. The skin (choice D) produces hormones like vitamin D when exposed to sunlight. Therefore, the liver is the only organ in the list that does not have hormone production.

Correct Answer: C

Rationale: The correct answer is C: cAMP and calcium. Peptide hormones bind to their receptors on the cell surface, activating G-proteins which then trigger the production of cAMP as a second messenger. cAMP then further activates protein kinases to initiate various cellular responses. Calcium is also a common second messenger in peptide hormone signaling pathways, regulating processes like muscle contraction and gene expression. Choice A is incorrect because peptide hormones themselves are not second messengers. Choice B is incorrect as glucose is not a common second messenger for peptide hormones. Choice D is incorrect as sodium is not typically involved in peptide hormone signaling pathways.