Sperm are stores in the ___________, ascend into the ___________ prior to ejaculation, and are discharged from the penis through the ____________

Correct Answer: B

Rationale: The correct answer is B. Sperm are stored in the epididymis, ascend into the vas deferens prior to ejaculation, and are discharged from the penis through the urethra. The epididymis is where sperm mature and are stored. The vas deferens is the duct through which sperm travels from the epididymis to the urethra for ejaculation. The urethra is the final pathway for sperm to exit the body. Choices A, C, and D are incorrect because they do not follow the correct anatomical pathway of sperm from storage to ejaculation.

Correct Answer: A

Rationale: The correct answer is A: Seminoma is the commonest pure testicular germ cell tumor. Seminoma is indeed the most common pure germ cell tumor of the testis, accounting for about 40-50% of cases. It typically presents in young adult males and has a good prognosis. Seminoma histologically consists of clear cytoplasmic glycogen and distinct cell borders. Choice B is incorrect as it seems to be incomplete. Choice C is incorrect as AFP (alpha-fetoprotein) increases in yolk sac tumors, not choriocarcinoma. Choice D is incorrect as Schiller-Duvall bodies are characteristic of embryonal carcinoma, not yolk sac tumors.

Correct Answer: C

Rationale: The testes originate in the abdominal cavity in a fetus. During development, they descend into the scrotal sac through the inguinal canal. This process is essential for proper sperm production as the scrotal environment provides optimal temperature for sperm development. The other choices are incorrect because the testes do not initially form in the scrotal sac, pelvic cavity, or retroperitoneal space. The correct sequence of descent from the abdominal cavity to the scrotal sac is crucial for normal reproductive function.

Correct Answer: D

Rationale: The correct answer is D because a low sperm count (less than 20 million per ml semen) can lead to infertility as it decreases the chances of successful fertilization. A high sperm count (choice A) is actually beneficial for fertility. Increased acrosomal activity (choice B) can enhance fertilization potential. Normal morphology (choice C) refers to the shape and size of sperm, which is important for fertility but not the primary factor in infertility due to low sperm count. Overall, a low sperm count is the most significant factor in infertility.

Correct Answer: D

Rationale: The correct answer is D: zygote. A zygote is formed when a sperm cell fertilizes an egg cell, resulting in a single cell with a full set of 46 chromosomes. This process is called fertilization and marks the beginning of a new individual. The other choices (A: spermatozoon, B: polar body, C: ovum) are not correct because a spermatozoon is a mature sperm cell with 23 chromosomes, a polar body is a byproduct of meiosis in the female reproductive system and has only 23 chromosomes, and an ovum is an unfertilized egg cell also containing 23 chromosomes.