Nursing Elites

1. Which vitamin is produced when the skin is exposed to sunlight?

• A. Vitamin A
• B. Vitamin D
• C. Vitamin K
• D. Vitamin E

Correct answer: B

Rationale: Vitamin D is the correct answer. When the skin is exposed to sunlight, it triggers a process where a form of cholesterol in the skin is converted into vitamin D. This vitamin plays a crucial role in aiding calcium absorption in the gut, which is essential for maintaining strong and healthy bones. Vitamin A (Choice A) is important for vision and immune function but is not produced by sunlight exposure. Vitamin K (Choice C) is known for its role in blood clotting and bone metabolism, but it is not produced by sunlight. Vitamin E (Choice D) is an antioxidant that protects cells from damage but is not synthesized in the skin through sunlight exposure.

2. Which of the following structures is responsible for filtering blood in the kidneys?

• A. Ureter
• B. Glomerulus
• C. Nephron
• D. Renal artery

Correct answer: B

Rationale: The correct answer is B: Glomerulus. The glomerulus, located in the nephron of the kidney, is a network of tiny blood vessels responsible for filtering blood. It removes waste products and excess substances to form urine. The ureter carries urine from the kidneys to the bladder and is not involved in blood filtration. The nephron is the functional unit of the kidney where blood is filtered and urine is produced. The renal artery supplies blood to the kidneys but is not directly involved in the filtration process.

3. What is the stage of mitosis during which the nuclear envelope reforms?

• A. Prophase
• B. Metaphase
• C. Telophase
• D. Cytokinesis

Correct answer: C

Rationale: During telophase, the nuclear envelope reforms around the separated sister chromatids at opposite poles of the cell. This stage marks the reversal of the processes that occurred during prophase, where the nuclear envelope breaks down. Metaphase is characterized by the alignment of chromosomes along the metaphase plate in the cell's center. Cytokinesis is the final step of cell division involving cytoplasmic division to form two daughter cells, but it does not involve the reformation of the nuclear envelope. Therefore, choice C (Telophase) is the correct answer as it specifically involves the reformation of the nuclear envelope, distinguishing it from the other stages of mitosis.

4. Neurons, the functional units of the nervous system, belong to which tissue type?

• A. Epithelial tissue
• B. Connective tissue
• C. Muscle tissue
• D. Nervous tissue

Correct answer: D

Rationale: Neurons are the functional units of the nervous system and are specialized cells that transmit nerve impulses. They belong to nervous tissue, which is the primary tissue type of the nervous system. Nervous tissue is composed of neurons and supporting cells called neuroglia. Choices A, B, and C are incorrect because epithelial tissue functions mainly in covering and lining body surfaces, connective tissue provides support and structure, and muscle tissue is responsible for movement. Neurons, being the basic functional units of the nervous system, are specifically classified under nervous tissue.

5. Which of the following correctly identifies a difference between the primary and secondary immune response?

• A. In the secondary response, macrophages migrate to the lymph nodes to present the foreign microorganism to helper T lymphocytes.
• B. The humoral immunity that characterizes the primary response is coordinated by B lymphocytes.
• C. The primary response is quicker and more powerful than the secondary response.
• D. Suppressor T cells are activated in the secondary response to prevent an overactive immune response.

Correct answer: C

Rationale: The correct answer is C. The primary immune response is slower and less powerful compared to the secondary immune response. During the primary response, immune cells encounter the antigen for the first time, necessitating the activation and proliferation of specific immune cells. In contrast, the secondary response benefits from memory cells that quickly recognize the antigen, enabling a faster and more potent immune response. Choices A, B, and D are incorrect. While macrophages play a role in presenting antigens to T cells, this is not a defining difference between primary and secondary responses. Humoral immunity involves B lymphocytes in both primary and secondary responses, so it does not differentiate the two. Suppressor T cells primarily function to regulate the immune response but are not a key factor distinguishing primary from secondary responses.

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