With respect to ejaculation which of the following statements is incorrect.

Correct Answer: A

Rationale: The correct answer is A because ejaculation is primarily controlled by the sympathetic nervous system, not the para-sympathetic system. The sympathetic nervous system triggers the contraction of smooth muscles to allow for ejaculation. Choice B is incorrect because ejaculation is not a result of summation of synaptic potentials, but rather a coordinated response. Choice C is incorrect because semen is expelled by rhythmic contractions of the pelvic floor muscles, not the urethral smooth muscle. Choice D is incorrect because ejaculation involves the discharge of sperm, seminal vesicle, prostatic secretions, and other fluids from the reproductive system.

Correct Answer: A

Rationale: The correct answer is A: Uterus. The uterus is a thick, muscular organ located in the lower abdomen where a developing baby grows during pregnancy. It can expand significantly to accommodate the growth of the fetus. The ovaries (B) are responsible for producing eggs, not for accommodating a developing baby. The vulva (C) refers to the external female genitalia, not the organ that supports pregnancy. The breast (D) is responsible for producing milk after childbirth, not for housing a developing baby.

Correct Answer: D

Rationale: The correct answer is D: vestibular bulbs. The male reproductive system consists of the prostate, testicles, and spermatic ducts, all essential for the production, storage, and transportation of sperm. Vestibular bulbs are actually part of the female reproductive system, involved in sexual arousal, and not found in the male reproductive system. Therefore, it is the only structure listed that is not a part of the male reproductive system.

Correct Answer: C

Rationale: The correct answer is C: the ejaculatory duct. The deferent duct, also known as the vas deferens, joins with the seminal vesicle duct to form the ejaculatory duct. This is where sperm from the testes and fluid from the seminal vesicles combine before entering the urethra during ejaculation. The other choices are incorrect because the seminal vesicle duct does not directly join with the deferent duct, the urethra is not formed by the deferent duct, and the epididymal duct is not involved in the formation of the ejaculatory duct.

Correct Answer: A

Rationale: The correct answer is A because the spermatozoon is indeed the primordial male cell, the precursor to all other male reproductive cells. Choice B is incorrect because the term "microscopic cell" is too broad and does not specifically define the spermatozoon. Choice C is incorrect because spermatozoa are actually formed within the seminiferous tubules of the testes, not the interstitial cells. Choice D is incorrect because spermatozoa are haploid cells, not diploid. Therefore, only choice A accurately describes the nature and origin of the spermatozoon.