Nursing Elites

1. Which phenomenon describes the bending of light as it travels from one medium to another with differing densities?

• A. Reflection
• B. Refraction
• C. Diffraction
• D. Dispersion

Correct answer: B

Rationale: Refraction is the phenomenon that describes the bending of light as it travels from one medium to another with differing densities. This bending occurs due to the change in speed of light as it moves from one medium to another, causing the light rays to change direction. Reflection refers to the bouncing back of light when it hits a surface, diffraction is the bending of light around obstacles, and dispersion is the separation of light into its different colors. Therefore, in the context of light moving through different media, refraction accurately describes the observed bending phenomenon.

2. From which type of tissue is the myelin sheath derived, a fatty substance that insulates nerve fibers?

• A. Epithelial tissue
• B. Muscle tissue
• C. Nervous tissue (glial cells)
• D. Connective tissue

Correct answer: C

Rationale: The myelin sheath, a fatty substance that insulates nerve fibers, is derived from nervous tissue, specifically glial cells. Glial cells, including oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system, are responsible for producing the myelin sheath that surrounds and insulates nerve fibers, aiding in the conduction of nerve impulses. Epithelial tissue (Choice A), Muscle tissue (Choice B), and Connective tissue (Choice D) are not responsible for producing the myelin sheath; instead, nervous tissue (glial cells) plays this crucial role.

3. What are the seven components of the digestive system?

• A. Mouth, esophagus, stomach, small intestine, large intestine, liver, pancreas
• B. Mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum
• C. Esophagus, stomach, liver, pancreas, small intestine, large intestine, rectum
• D. Pharynx, stomach, liver, pancreas, small intestine, large intestine, rectum

Correct answer: B

Rationale: The correct answer is B. The seven components of the digestive system are the mouth, pharynx, esophagus, stomach, small intestine, large intestine, and rectum. The mouth begins the process of digestion by chewing and mixing food with saliva. The pharynx serves as a passageway for food and air. The esophagus transports food from the mouth to the stomach. The stomach aids in digestion and acts as a temporary storage site. The small intestine is where most of the digestion and absorption of nutrients occur. The large intestine absorbs water and salts, forming feces. The rectum stores feces until they are eliminated through the anus. The other choices are incorrect as they do not list all seven essential components of the digestive system.

4. Which hormone, produced by the pancreas, is released in response to low blood sugar levels and stimulates the release of glucose into the bloodstream?

• A. Insulin
• B. Glucagon
• C. Cortisol
• D. Thyroxine

Correct answer: B

Rationale: Glucagon is the hormone produced by the pancreas that is released in response to low blood sugar levels. It acts to stimulate the release of glucose into the bloodstream by promoting the breakdown of glycogen in the liver. Insulin, conversely, is released in response to high blood sugar levels and promotes the uptake of glucose by cells. Cortisol is a steroid hormone produced by the adrenal glands that regulates metabolism and the immune response. Thyroxine is a hormone produced by the thyroid gland that regulates metabolism but is not involved in responding to low blood sugar levels.

5. What is the general formula for an alkyl halide?

• A. CₙH₂ₙ
• B. CₙH₂ₙ₊₂
• C. CₙH₂ₙ₊₁X
• D. CₙH₂ₙO

Correct answer: C

Rationale: The correct answer is option C, 'CₙH₂ₙ₊₁X.' This is the general formula for an alkyl halide, where X represents a halogen atom (such as fluorine, chlorine, bromine, or iodine), and the hydrocarbon chain is represented by CₙH₂ₙ₊₁. Option A, 'CₙH₂ₙ,' is incorrect because it does not account for the presence of a halogen atom. Option B, 'CₙH₂ₙ₊₂,' is incorrect as it represents an alkene, not an alkyl halide. Option D, 'CₙH₂ₙO,' is also incorrect as it suggests the presence of oxygen, which is not characteristic of alkyl halides.

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