ATI RN
Human Reproductive System Questions
Question 1 of 5
People lacking melanocytes are deaf. These cells function as part of:
Correct Answer: D
Rationale: The correct answer is D: stria vascularis. Melanocytes are present in the stria vascularis of the cochlea, which is essential for maintaining the endocochlear potential and supporting the function of the hair cells. Without melanocytes, the stria vascularis cannot maintain the proper ion balance necessary for hearing, leading to deafness. A: Hair cells are responsible for converting sound vibrations into electrical signals and are not directly related to melanocytes. B: The modiolus is a bony structure in the cochlea that houses the spiral ganglion, which transmits signals from the hair cells to the brain. It is not directly involved with melanocytes. C: The spiral limbus is a structure in the cochlea that supports the organ of Corti and is not directly related to melanocytes.
Question 2 of 5
One treatment for erectile dysfunction requires the injection of a substance into the corpora cavernosa of the penis. The injection of which of the following causes an erection?
Correct Answer: C
Rationale: Alprostadil is the correct answer because it is a prostaglandin E1 analog that dilates blood vessels in the corpora cavernosa, promoting blood flow and causing an erection. Norepinephrine (choice A) constricts blood vessels and inhibits erection. A substance that inhibits nitric oxide formation (choice B) is counterproductive as nitric oxide is essential for vasodilation. Angiotensin II (choice D) constricts blood vessels and does not promote erection. Therefore, C is the correct choice for inducing an erection through vasodilation in the corpora cavernosa.
Question 3 of 5
As menstruation ends estrogen levels in the blood rise rapidly. What is the source of the estrogen?
Correct Answer: B
Rationale: The correct answer is B: Developing follicles. After menstruation, the developing follicles in the ovaries produce estrogen. This estrogen is responsible for thickening the endometrium in preparation for potential implantation of a fertilized egg. The corpus luteum produces progesterone, not estrogen. The endometrium is the inner lining of the uterus and is not a direct source of estrogen. Stromal cells of the ovaries are supportive cells and do not produce estrogen.
Question 4 of 5
During pregnancy, the uterine smooth muscle is quiescent. During the 9th month of gestation the uterine muscle becomes progressively more excitable. What factors contribute to the increase in excitability?
Correct Answer: B
Rationale: The correct answer is B: Progesterone synthesis by the placenta decreases. Progesterone maintains uterine quiescence during pregnancy by inhibiting uterine contractions. As progesterone levels decline towards the end of pregnancy, the uterine muscle becomes more excitable. Placental estrogen synthesis (Choice A) does not directly affect uterine excitability. Uterine blood flow (Choice C) is not a direct factor in uterine muscle excitability. Prostaglandin E2 (Choice D) actually increases towards the end of pregnancy, contributing to uterine contractions rather than decreasing excitability.
Question 5 of 5
Levels of transcortin are elevated in a pregnant woman. Which of the following laboratory findings would be expected in this patient?
Correct Answer: A
Rationale: Rationale: Elevated levels of transcortin in a pregnant woman lead to an increase in total plasma cortisol concentration. Transcortin binds to cortisol, increasing its total concentration but reducing the amount of free (non-protein-bound) cortisol. Choice A is correct as total cortisol concentration increases due to transcortin binding. Choices B and D are incorrect as free cortisol concentration decreases. Choice C is incorrect as total cortisol concentration is elevated, not decreased.