ATI RN

1. What is the function of the corpus luteum?

• A. is where fertilization usually takes place
• B. secretes hormones that prepare the lining of the uterus to receive a fertilized ovum
• C. is one of two long, thin structures that lead to the hollow, softly lined uterus
• D. is one of two walnut-sized organs located deep inside a woman's abdomen

Correct Answer: B

Rationale: The correct answer is B. The corpus luteum is a temporary endocrine structure in the ovary that forms after ovulation. It secretes hormones, particularly progesterone, which help prepare the uterine lining for possible implantation of a fertilized ovum. This process is crucial for maintaining a potential pregnancy. Choices A, C, and D are incorrect. Choice A is inaccurate as fertilization typically occurs in the fallopian tubes. Choice C describes the fallopian tubes, not the corpus luteum. Choice D refers to the ovaries, not specifically the corpus luteum.

2. During Irina's first week of pregnancy, __________.

• A. heart muscles begin to develop
• B. the zygote multiplies and forms a blastocyst
• C. a primitive brain and spinal cord appear
• D. the embryo can move

Correct Answer: B

Rationale: During the first week of pregnancy, the zygote (fertilized egg) undergoes rapid cell divisions and forms a blastocyst. This is a crucial stage where the cells differentiate and specialize, setting the foundation for the development of the embryo. It is during this time that the zygote implants itself into the uterine wall, initiating the process of pregnancy. Choices A, C, and D are incorrect because during the first week of pregnancy, the focus is on the initial development and multiplication of the zygote, not on the development of heart muscles, a primitive brain and spinal cord, or the embryo's ability to move.

3. During pregnancy, the placenta __________.

• A. forms in the second trimester of pregnancy
• B. encloses the developing organism in amniotic fluid
• C. contains one large vein that delivers nutrients to the embryo
• D. delivers food and oxygen to the developing organism

Correct Answer: D

Rationale: The placenta delivers food and oxygen to the developing organism during pregnancy. It is a temporary organ that forms in the first trimester of pregnancy. Choice A is incorrect as the placenta forms in the first trimester, not the second trimester. Choice B is incorrect as the amniotic sac, not the placenta, encloses the developing organism in amniotic fluid. Choice C is incorrect as the placenta contains blood vessels (arteries and veins) that deliver nutrients to the embryo, not just one large vein.

4. Jalynn is in the last half of the first month of her pregnancy. Which of the following is developing the fastest?

• A. circulatory system
• B. endocrine system
• C. nervous system
• D. skin

Correct Answer: C

Rationale: During the last half of the first month of pregnancy, the nervous system develops the fastest among the options provided. This rapid development of the nervous system is crucial for the overall growth and functioning of the fetus. The nervous system includes the brain and spinal cord, which are essential for various bodily functions and will continue to develop throughout the pregnancy. The circulatory system, although important, does not develop at the fastest rate during this stage. The endocrine system and skin also play significant roles in the development of the fetus but are not the systems that develop the fastest in the last half of the first month of pregnancy.

5. Katie wonders when she will first be able to hear her fetus's heartbeat through a stethoscope. You tell her that this should happen by the __________.

• A. fourth week of pregnancy
• B. third month of pregnancy
• C. end of the second trimester
• D. beginning of the third trimester

Correct Answer: B

Rationale: The correct answer is the third month of pregnancy (choice B). During the third month of pregnancy, which is around 9-12 weeks, a fetal heartbeat can typically be heard using a stethoscope. This is an exciting milestone for expectant parents as it provides reassurance about the baby's well-being. Choices A, C, and D are incorrect because by the fourth week of pregnancy, the fetal heartbeat is not usually detectable with a stethoscope. The end of the second trimester and the beginning of the third trimester are too late in the pregnancy timeline for this milestone.