Nursing Elites

1. What is the primary function of the placenta during pregnancy?

• A. Produce insulin
• B. Facilitate gas exchange between mother and fetus
• C. Excrete waste products from the fetus
• D. All of the above

Correct answer: B

Rationale: The primary function of the placenta during pregnancy is to facilitate the exchange of oxygen and carbon dioxide between the mother and the fetus. This ensures that the fetus receives oxygen and eliminates carbon dioxide, supporting its growth and development. While the placenta also allows for the transfer of nutrients and waste products between the mother and the fetus, its main role is to ensure proper gas exchange. Therefore, choices A, C, and D are incorrect as the primary role of the placenta is not to produce insulin or excrete waste products from the fetus. Selecting the correct answer, choice B, highlights the crucial role of the placenta in providing oxygen to the fetus and removing carbon dioxide, which are essential for fetal well-being and development.

2. How are the bones of the skull classified?

• A. Long bones
• B. Short bones
• C. Flat bones
• D. Irregular bones

Correct answer: C

Rationale: The bones of the skull are classified as flat bones. Flat bones are thin, flattened, and usually curved bones that provide protection to underlying organs and have a large surface area for muscle attachment. The skull bones fit this description as they protect the brain and have a broad surface for muscle attachment. Choice A (Long bones), B (Short bones), and D (Irregular bones) are incorrect classifications. Long bones are typically found in the extremities like the arms and legs, short bones are cube-shaped like the wrist and ankle bones, and irregular bones have complex shapes like the vertebrae. These classifications do not describe the bones of the skull, which are predominantly flat bones.

3. Which valve prevents blood from entering the left atrium when the ventricles contract?

• A. Pulmonary valve
• B. Tricuspid valve
• C. Mitral valve
• D. Aortic valve

Correct answer: C

Rationale: The correct answer is the mitral valve, also known as the bicuspid valve. The mitral valve prevents blood from flowing back into the left atrium during ventricular contraction. The tricuspid valve is located between the right atrium and right ventricle, the pulmonary valve is between the right ventricle and the pulmonary artery, and the aortic valve is situated between the left ventricle and the aorta. Therefore, choices A, B, and D are incorrect as they are not related to preventing blood from entering the left atrium during ventricular contraction.

4. What are the structural and functional units responsible for creating and transporting urine, located in the cortex of the kidney?

• A. Glomerulus
• B. Nephrons
• C. Loops of Henle
• D. Distal tubules

Correct answer: B

Rationale: The correct answer is 'Nephrons.' Nephrons are the structural and functional units of the kidneys responsible for creating and transporting urine. Each kidney contains thousands of nephrons located in the cortex and medulla. The nephron consists of the renal corpuscle, which includes the glomerulus, and the renal tubule, which consists of the proximal tubule, loops of Henle, and distal tubule. While the glomerulus, loops of Henle, and distal tubules are all parts of the nephron, the nephrons as a whole are specifically responsible for creating and transporting urine.

5. Two mice are both heterozygous for two traits: white fur (Ww) and short fur (Ss). Their offspring are most likely to have which of the following genotypes for these traits?

• A. wwss
• B. WWSS
• C. WwSs
• D. WWSs

Correct answer: C

Rationale: When two mice that are heterozygous for white fur (Ww) and short fur (Ss) mate, they can produce offspring with different combinations of the two traits. The Punnett square for this cross shows that the most likely genotype for the offspring is WwSs. In this case, each offspring receives one allele for white fur (W) and one for short fur (S) from each parent, resulting in a heterozygous genotype for both traits. Choice A (wwss) is incorrect as it represents a homozygous recessive genotype for both traits. Choice B (WWSS) is also incorrect as it represents a homozygous dominant genotype for both traits. Choice D (WWSs) is incorrect as it represents a genotype where one trait is homozygous dominant (W) and the other is heterozygous (S), which is not the most likely outcome based on the given parental genotypes.

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