Nokea
Which structure is the site of sperm production?
- A. Vas deferens
- B. Seminiferous tubules
- C. Albuginea
- D. Epididymis
Correct Answer: B
Rationale: The correct answer is B: Seminiferous tubules. These tubules are located within the testes and are the specific structures where sperm production occurs through a process called spermatogenesis. Sperm cells are produced within the seminiferous tubules and then mature as they move through the epididymis (choice D) and vas deferens (choice A). The albuginea (choice C) is the tough outer covering of the testes and does not play a direct role in sperm production. Therefore, the seminiferous tubules are the primary site for sperm production in the male reproductive system.
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With respect to ejaculation which of the following statements is incorrect.
- A. ejaculation is the result of para-sympathetic stimulation
- B. ejaculation results from the summation of synaptic potentials
- C. during ejaculation semen is expelled by rapid contraction of the urethral smooth muscle
- D. ejaculation results is the discharge of sperm, seminal vesicle and prostatic secretions
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.
Regarding respiratory system of fetus
- A. Respiratory bud starts to appear at the ventral wall of foregut at approximately week 10 of gestation
- B. There are 4 stages of development of respiratory system
- C. Development of respiratory tract is not complete until the last week of fetal development.
- D. Epithelial respiratory is derived from endodermal
Correct Answer: A
Rationale: The correct answer is A because the respiratory bud does indeed start to appear at the ventral wall of the foregut around week 10 of gestation. This marks the beginning of respiratory system development. Choice B is incorrect as there are actually 5 stages of respiratory system development. Choice C is also incorrect as the development of the respiratory tract is not fully complete until after birth, not just in the last week of fetal development. Choice D is incorrect because the epithelial respiratory lining is derived from endoderm, not endodermal.
_______ is a lytic enzyme released by the sperm.
- A. Hyaluronidase
- B. Trypsin
- C. Helicase
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A: Hyaluronidase. This enzyme is released by the sperm to help penetrate the outer layer of the egg during fertilization. Hyaluronidase specifically breaks down hyaluronic acid present in the cumulus cells surrounding the egg. Trypsin is a digestive enzyme found in the pancreas, not involved in sperm function. Helicase is an enzyme involved in DNA replication and repair, not released by sperm. "None of the above" is incorrect as hyaluronidase is indeed released by the sperm.
RU486 causes abortion if it is administered before or soon after implantation. What is the specific effect of RU486?
- A. It binds to luteinizing hormone receptors, stimulating the secretion of progesterone from the corpus luteum
- B. It blocks progesterone receptors so that progesterone has no effect within the body
- C. It blocks the secretion of follicle-stimulating hormone by the pituitary
- D. It blocks the effects of oxytocin receptors in the uterine muscle
Correct Answer: B
Rationale: The correct answer is B, as RU486 blocks progesterone receptors, preventing progesterone from exerting its effects. Progesterone is crucial for maintaining the uterine lining to support a pregnancy. By blocking progesterone receptors, RU486 causes the uterine lining to break down, leading to the expulsion of the embryo and ultimately causing abortion.
Choice A is incorrect because RU486 does not bind to luteinizing hormone receptors or stimulate progesterone secretion.
Choice C is incorrect because RU486 does not block the secretion of follicle-stimulating hormone; its mechanism of action is specific to progesterone receptors.
Choice D is incorrect because RU486 does not block the effects of oxytocin receptors in the uterine muscle; its primary action is on progesterone receptors.
Chronic cervicitis is treated with
- A. Antibiotics
- B. Antifungals
- C. Antivirals
- D. Anti-inflammatory drugs
Correct Answer: A
Rationale: Antibiotics are typically used to treat chronic cervicitis caused by bacterial infections.