Dopamine and homovanillic acid are secreted in ______________.

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: 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.

Correct Answer: B

Rationale: Certainly! The secretion of oxytocin is increased by the dilation of the cervix. When the cervix dilates during childbirth, it triggers the release of oxytocin from the posterior pituitary gland. This hormone plays a crucial role in stimulating uterine contractions during labor and delivery. Milk ejection (choice A) is primarily regulated by oxytocin but does not directly increase its secretion. Increased prolactin levels (choice C) stimulate milk production, not oxytocin secretion. Increased extracellular fluid (ECF) volume (choice D) is not directly related to oxytocin secretion.

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.