ATI RN

1. During which period does the germinal period occur?

• A. Occurs during the second trimester of pregnancy
• B. Lasts about six weeks
• C. Lasts about two weeks
• D. Is the final period of a 38-week pregnancy

Correct Answer: C

Rationale: The germinal period lasts about two weeks and occurs during the first two weeks of pregnancy. This is the time when the fertilized egg implants into the uterus and begins to divide rapidly. It is followed by the embryonic period, which lasts from about week 3 to week 8 of pregnancy. Choice A is incorrect because the germinal period happens in the early stages of pregnancy, not the second trimester. Choice B is incorrect because the germinal period typically lasts about two weeks, not six. Choice D is incorrect because the germinal period is an early stage of pregnancy and not the final period of a 38-week pregnancy.

2. What is the function of the amniotic fluid?

• A. Delivers food and oxygen to the developing organism
• B. Helps keep the temperature of the prenatal world constant
• C. Delivers nutrients and removes waste products
• D. Produces blood cells until the organs are mature enough to take over this function

Correct Answer: B

Rationale: The correct answer is B: 'Helps keep the temperature of the prenatal world constant.' Amniotic fluid helps maintain a stable and warm environment for the developing organism, assisting in regulating the temperature. This fluid also acts as a cushion, protecting the fetus from physical harm. Choices A, C, and D are incorrect because while amniotic fluid provides protection and support to the developing organism, it does not directly deliver food, oxygen, nutrients, or remove waste products, nor does it produce blood cells as the organs eventually take over this function.

3. During prenatal development, the ectoderm becomes the __________.

• A. muscles and skeleton
• B. nervous system and skin
• C. circulatory system and other internal organs
• D. digestive system, lungs, urinary tract, and glands

Correct Answer: B

Rationale: The correct answer is B: nervous system and skin. The nervous system, which includes the brain, spinal cord, and nerves, as well as the skin, develop from the ectoderm layer of cells during prenatal development. Choice A is incorrect because muscles and skeleton develop from mesoderm. Choice C is incorrect because the circulatory system and other internal organs develop from mesoderm and endoderm. Choice D is incorrect because the digestive system, lungs, urinary tract, and glands develop from endoderm.

4. During the second month of pregnancy, __________.

• A. the umbilical cord first appears as a primitive body stalk
• B. touch sensitivity extends to most of the body
• C. the heart develops separate chambers
• D. the heartbeat can be heard through a stethoscope

Correct Answer: C

Rationale: During the second month of pregnancy, the heart of the developing fetus begins to develop separate chambers, forming the structure necessary for a fully functioning heart. This is a significant milestone in the prenatal development process. Choices A, B, and D are incorrect because the appearance of the umbilical cord as a primitive body stalk typically occurs around week 5-6, touch sensitivity extending to most of the body is more characteristic of the end of the second trimester, and the heartbeat is usually detectable through a stethoscope around the 18th to 20th week of pregnancy, not during the second month.

5. __________ increases tenfold from the twentieth week until birth.

• A. Amniotic fluid
• B. Brain weight
• C. Fetal length
• D. Neuron production

Correct Answer: B

Rationale: Brain weight increases tenfold from the twentieth week until birth. This rapid growth and development of the brain during the prenatal period is crucial for setting the foundation for future cognitive and neurological functions. Choices A, C, and D are incorrect because although they also undergo changes during prenatal development, none of them increase tenfold from the twentieth week until birth, unlike brain weight.