Nursing Elites

1. Myelin sheath is a fatty substance that insulates and protects the long extensions of some nerve cells. It is produced by:

• A. Schwann cells
• B. Astrocytes
• C. Neurons
• D. Oligodendrocytes

Correct answer: A

Rationale: Schwann cells are indeed responsible for producing the myelin sheath in the peripheral nervous system. These cells wrap around axons to form the myelin sheath, which enhances the speed of nerve impulse conduction. In the central nervous system, oligodendrocytes are responsible for producing the myelin sheath. Astrocytes provide support and maintenance functions for neurons, while neurons are the nerve cells themselves and do not produce myelin. Therefore, the correct answer is Schwann cells as they are specifically involved in myelin production in the peripheral nervous system.

2. What is the function of the immune system?

• A. To transport oxygen
• B. To fight infection
• C. To digest food
• D. To produce hormones

Correct answer: B

Rationale: The correct answer is B: 'To fight infection.' The immune system's primary function is to protect the body from infections and foreign invaders by recognizing and responding to pathogens. It plays a crucial role in maintaining overall health and preventing diseases caused by harmful microorganisms. Choices A, C, and D are incorrect because the immune system is not responsible for transporting oxygen, digesting food, or producing hormones. These functions are carried out by other systems in the body, such as the respiratory system, digestive system, and endocrine system, respectively.

3. In the K-capture process, a type of electron capture, from which electron shell does the electron get captured?

• A. The outermost s-orbital
• B. An inner p-orbital
• C. An inner d-orbital
• D. Any available electron shell

Correct answer: B

Rationale: The K-capture process involves the capture of an electron from the innermost electron shell, known as the K-shell. The K-shell comprises s and p orbitals. During the K-capture process, an electron is specifically captured from an inner p-orbital within the K-shell. Choices A, C, and D are incorrect because K-capture involves capturing an electron from the innermost shell (K-shell) which consists of s and p orbitals, not the outermost s-orbital, inner d-orbital, or any available electron shell.

4. Immunoglobulin G (IgG) is the most abundant antibody type, responsible for:

• A. Immediate allergic reactions
• B. Neutralizing toxins and viruses
• C. Activating other immune cells
• D. Protecting newborns from infections

Correct answer: B

Rationale: Immunoglobulin G (IgG) is indeed the most prevalent antibody type in the blood and tissue fluids. Its primary functions include neutralizing toxins and viruses, promoting phagocytosis, and activating the complement system. IgG plays a crucial role in long-term immunity and provides passive immunity to newborns by crossing the placenta, safeguarding them from infections. Immediate allergic reactions are mainly mediated by IgE, not IgG. While IgM is known for activating other immune cells, IgG focuses on other key functions within the immune response, such as neutralizing pathogens and enhancing phagocytosis. Therefore, the correct answer is B, as IgG is primarily involved in neutralizing toxins and viruses, rather than the other options presented.

5. When ethanol (C₂H₅OH) reacts with sodium metal (Na), what is the product?

• A. Ethene (C₂H₄)
• B. Sodium ethoxide (C₂H₅ONa)
• C. Ethane (C₂H₆)
• D. Sodium acetate (CH₃COONa)

Correct answer: B

Rationale: When ethanol (C₂H₅OH) reacts with sodium metal (Na), the product formed is Sodium ethoxide (C₂H₅ONa). This reaction is a classic example of a metal displacing hydrogen in an alcohol to form an alkoxide. In this specific case, sodium replaces the hydrogen in ethanol, resulting in the formation of sodium ethoxide. Choice A, Ethene (C₂H₄), is incorrect as it is a different compound formed from the dehydration of ethanol, not its reaction with sodium. Choice C, Ethane (C₂H₆), is incorrect as it is a saturated hydrocarbon, not the product of the reaction of ethanol with sodium metal. Choice D, Sodium acetate (CH₃COONa), is incorrect as it involves acetic acid, not ethanol, reacting with sodium to form the salt sodium acetate.

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