Which of the following is NOT a mechanism of hormone action?

Correct Answer: B

Rationale: The correct answer is B: cellular mutations occur. Hormones typically act through binding to specific receptors on target cells to initiate a signaling cascade. This process does not involve inducing mutations in the cell's DNA. Plasma membrane permeability changes, enzyme activation/inactivation, and stimulation of mitosis are all well-established mechanisms of hormone action. Therefore, B is the correct answer as it does not align with the usual mechanisms by which hormones exert their effects.

Correct Answer: A

Rationale: Step-by-step rationale: 1. Dopamine and homovanillic acid are neurotransmitters. 2. Neuroblastoma is a type of cancer that originates in neuroblasts, which are immature nerve cells. 3. Neuroblastoma can produce neurotransmitters like dopamine and homovanillic acid. 4. Therefore, dopamine and homovanillic acid are secreted in neuroblastoma. Summary: - Choice A is correct as neuroblastoma can secrete dopamine and homovanillic acid. - Choices B and C are incorrect as they are unrelated to the secretion of these neurotransmitters.

Correct Answer: C

Rationale: The correct answer is C, glucagon and epinephrine. Glucagon stimulates the liver to release glucose into the bloodstream, increasing blood sugar levels. Epinephrine, also known as adrenaline, has a similar effect by promoting the breakdown of glycogen into glucose. Insulin (choice A) decreases blood sugar by promoting glucose uptake into cells. Growth hormone (choice B) mainly affects growth and metabolism but doesn't directly increase blood sugar. Antidiuretic hormone (choice D) regulates water balance and has no direct effect on blood sugar levels.

Correct Answer: B

Rationale: Estrogens and progesterone are primarily produced by the ovaries in females. The ovaries are the main reproductive organs responsible for the production of these hormones, essential for menstrual cycle regulation and pregnancy support. The correct answer is B because the ovaries are the key glands that synthesize and release estrogen and progesterone. Choices A, C, and D are incorrect because the testes primarily produce testosterone, the adrenal glands produce cortisol and adrenaline, and the hypothalamus is a brain region involved in hormone regulation, not hormone production.

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.