Which blood vessel in the fetus has the highest Po2?

Correct Answer: B

Rationale: The correct answer is B: Ductus venosus. The ductus venosus carries oxygenated blood from the umbilical vein to the inferior vena cava, bypassing the liver. This blood has the highest Po2 among the choices because it is coming directly from the placenta, where oxygen exchange occurs. The other choices (A, C, D) carry deoxygenated blood or blood with lower oxygen content in the fetal circulation. The ductus arteriosus shunts blood from the pulmonary artery to the aorta, so it carries deoxygenated blood. The ascending aorta and left atrium receive mixed oxygenated and deoxygenated blood, not the highest Po2.

Correct Answer: D

Rationale: The correct answer is D: Bulbourethral fluid. Semen is composed of sperm, seminal fluid, and prostatic fluid. Bulbourethral fluid is not a component of semen but contributes to pre-ejaculatory fluid. This fluid is released from the Cowper's glands and serves to lubricate the urethra prior to ejaculation. The other choices (A, B, C) are all essential components of semen that play crucial roles in sperm transport, nourishment, and protection.

Correct Answer: D

Rationale: The correct answer is D because the innermost lining of the vagina does not slough off periodically like the uterine lining does during menstruation. The vaginal lining is composed of stratified squamous epithelium that does not undergo the shedding process seen in the endometrium. This is important for maintaining the integrity and functionality of the vagina. Choices A, B, and C are true statements about the vagina. A: The vagina serves as the birth canal. B: The distal end of the vagina is partially enclosed by the hymen. C: The vagina is the female organ of copulation.

Correct Answer: C

Rationale: The correct answer is C: round ligament. The round ligament holds the uterus in place laterally. It is a band of tissue that connects the uterus to the groin region. This ligament provides support and stability to the uterus during movements and changes in position. Choice A (8 place, laterally) and Choice D (100) are nonsensical and do not correspond to any anatomical structure or location. Choice B (25) is also incorrect as it does not exist as a ligament involved in supporting the uterus. In summary, the round ligament is the correct choice as it is the specific ligament responsible for holding the uterus in place laterally, providing essential support and stability.

Correct Answer: D

Rationale: The correct answer is D: oogenesis. Oogenesis is the process of creating female gametes (eggs) through cell division in the ovaries. This process involves several stages including mitosis, meiosis, and maturation. Spermatogenesis (B) is the process of creating male gametes (sperm) in the testes. The areola (A) is the pigmented area around the nipple, not a reproductive process. The lactiferous sinus (C) is a structure within the breast involved in milk storage, not the process of creating female gametes.