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 property of a wave determines its loudness in sound waves?

• A. Amplitude
• B. Wavelength
• C. Frequency
• D. Speed

Correct answer: A

Rationale: The correct answer is Amplitude. Amplitude is the property of a wave that determines its loudness in sound waves. The greater the amplitude of a sound wave, the louder the sound will be perceived. Wavelength and frequency are related to the pitch of the sound, with wavelength affecting the tone quality and frequency determining the pitch. Speed, on the other hand, is a characteristic of how fast the wave travels through a medium and does not directly influence the loudness of the sound.

3. The pancreas secretes digestive enzymes into the small intestine. What enzyme breaks down proteins into amino acids?

• A. Pepsin
• B. Lipase
• C. Amylase
• D. Trypsin

Correct answer: D

Rationale: Trypsin is the correct enzyme that breaks down proteins into amino acids. It is produced by the pancreas and released into the small intestine to facilitate protein digestion. Pepsin is an enzyme from the stomach that also breaks down proteins, amylase targets carbohydrates, and lipase works on fats. In this context, since the question specifies the pancreas and small intestine, the correct answer is Trypsin as it is the pancreatic enzyme responsible for protein breakdown in the small intestine.

4. Which type of lens focuses parallel light rays to a single point?

• A. Concave lens
• B. Convex lens
• C. Cylindrical lens
• D. Plano lens

Correct answer: B

Rationale: A convex lens focuses parallel light rays to a single point by causing them to converge. This lens is thicker in the center than at the edges, which helps in converging the light rays. Convex lenses are commonly used for tasks like magnification and focusing due to their ability to bring distant light rays to a single focal point. Choice A, the concave lens, diverges light rays rather than converging them, making it incorrect. Choice C, the cylindrical lens, is designed to focus light along one axis rather than converging parallel light rays to a single point. Choice D, the plano lens, has no curvatures to bend or focus light rays, so it does not converge parallel light rays.

5. What type of bond forms between elements when they share electrons?

• A. Covalent bond
• B. Ionic bond
• C. Metallic bond
• D. Hydrogen bond

Correct answer: A

Rationale: The correct answer is A: Covalent bond. In a covalent bond, atoms share electrons, leading to the creation of a strong attraction that holds them together. This type of bond is characterized by the sharing of electron pairs between atoms, resulting in the formation of molecules. Choice B, Ionic bond, involves the transfer of electrons from one atom to another, creating charged ions that attract each other. Choice C, Metallic bond, refers to the sharing of electrons among a sea of delocalized electrons in a metal structure. Choice D, Hydrogen bond, is a weak electrostatic attraction between a hydrogen atom and an electronegative atom like oxygen or nitrogen, not involving the sharing of electrons.

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