The spongy tissue of the penis fills

Correct Answer: D

Rationale: The spongy tissue of the penis fills with blood during an erection to cause the penis to become rigid. This process is essential for maintaining an erection during sexual activity. Spermatogenesis refers to the production of sperm, not the filling of spongy tissue. Circumcision does not involve the filling of spongy tissue with blood. Ejaculation is the release of semen and does not involve the filling of spongy tissue. Therefore, the correct answer is D as it accurately describes the physiological process of penile erection.

Correct Answer: A

Rationale: The correct answer is A: oxytocin. Oxytocin is not a placental hormone because it is produced by the hypothalamus and stored in the posterior pituitary gland. Placental hormones are specifically produced by the placenta during pregnancy. Relaxin, estrogen, and human chorionic gonadotropin hormone are all placental hormones involved in various functions during pregnancy. Oxytocin, on the other hand, plays a role in uterine contractions during labor and milk ejection during breastfeeding, but it is not produced by the placenta.

Correct Answer: B

Rationale: The correct answer is B because it is incorrect to say that a male erection is triggered by motor inputs to the higher brain regions. Erections are primarily controlled by the autonomic nervous system, specifically the parasympathetic division. Parasympathetic activity leads to vasodilation of penile blood vessels, resulting in increased blood flow and erection. Choices A, C, and D are incorrect because during an erection, there is indeed an increase in parasympathetic activity, a decrease in sympathetic activity, and dilation of arterioles in the penis.

Correct Answer: A

Rationale: The correct answer is A: Vagina. The vagina is the muscular passageway from the cervix to the outside of the female's body, serving as the birth canal. It is where sexual intercourse occurs and where menstrual flow exits the body. The uterus (B) is the organ where a fertilized egg implants and develops into a fetus, not the birth canal. Fallopian tubes (C) are where fertilization of an egg typically occurs, not part of the birth canal. Obstetrician (D) is a medical professional specializing in childbirth and pregnancy, not a part of the female reproductive anatomy.

Correct Answer: C

Rationale: The correct answer is C: Implantation. After fertilization, the embryo travels through the fallopian tube and reaches the uterus. During implantation, the embryo attaches itself to the endometrium lining of the uterus for further development. Menopause (A) is the cessation of menstrual cycles, ovulation (B) is the release of an egg from the ovary, and menstruation (D) is the shedding of the uterine lining if fertilization does not occur.