Regarding lactation

Correct Answer: A

Rationale: The correct answer is A because milk production is indeed controlled by prolactin, a hormone secreted by the anterior pituitary gland. Prolactin stimulates the alveoli in the breast to produce milk. Option B is incorrect because estrogen and prolactin actually work synergistically to promote lactation. Option C is incorrect as the nipple is lubricated by Montgomery glands, not sebaceous glands. Option D is incorrect because myoepithelial cell contraction helps in milk ejection, not in milk production.

Correct Answer: C

Rationale: The correct answer is C: spermatogonia. At the age of five, boys have not reached puberty yet, so they do not produce sperm cells. Spermatogonia are the precursor cells that give rise to sperm cells later in puberty. Spermatocytes are the cells that undergo meiosis to form sperm cells, spermatozoa are mature sperm cells, and spermatids are the immediate precursors to sperm cells. Therefore, the only cells present in a male age five would be spermatogonia, as they are the early-stage cells in the process of spermatogenesis.

Correct Answer: D

Rationale: The correct answer is D: GnRH. Gonadotropin-releasing hormone (GnRH) is released from the hypothalamus, stimulating the pituitary gland to produce FSH and LH, which then trigger the changes of puberty. FSH and LH are not the initial hormones that start puberty, but rather the result of GnRH stimulation. Testosterone and ICSH are also involved in puberty but are not the primary hormone that initiates the process.

Correct Answer: A

Rationale: The correct answer is A: uterine tube. During ovulation, the mature oocyte is released from the ovary and travels through the uterine tube (fallopian tube) towards the uterus for potential fertilization. The uterine tube is the pathway for the oocyte to reach the uterus. Choices B, C, and D are incorrect because the oocyte does not directly pass into the uterus, pelvic cavity, or ovary during ovulation.

Correct Answer: A

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.