Nursing Elites

1. Which cells myelinate neurons in the PNS?

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

Correct answer: C

Rationale: Schwann cells are the glial cells responsible for myelinating neurons in the peripheral nervous system (PNS). They form the myelin sheath around axons, which helps in the conduction of electrical impulses. Oligodendrocytes, on the other hand, myelinate neurons in the central nervous system (CNS). Astrocytes primarily provide support for neuronal function by regulating the chemical environment around neurons and maintaining the blood-brain barrier. Microglia are part of the immune response in the CNS, where they act as the resident macrophages, playing a role in immune surveillance and response to injury or disease. Therefore, the correct answer is Schwann cells (Choice C) as they specifically myelinate neurons in the PNS, differentiating them from the other cell types mentioned in the choices.

2. What is insulin, where is it produced, and what is its function?

• A. Produced in the liver, regulates fat storage
• B. Produced in the pancreas, regulates blood sugar
• C. Produced in the stomach, aids in digestion
• D. Produced in the kidneys, controls hydration

Correct answer: B

Rationale: Insulin is a hormone produced in the pancreas. Its primary function is to regulate blood sugar levels by facilitating the uptake of glucose by cells for energy. The other choices are incorrect as insulin is not produced in the liver (Choice A), stomach (Choice C), or kidneys (Choice D), and its function is not related to fat storage, digestion, or hydration. Therefore, the correct answer is B.

3. Which statement below best describes the process of condensation?

• A. Condensation is the process of changing from a gas to a liquid.
• B. Condensation is the process of changing from a liquid to a gas.
• C. Condensation is the process of changing from a solid to a liquid.
• D. Condensation is the process of changing from a solid to a gas.

Correct answer: A

Rationale: The correct answer is A: 'Condensation is the process of changing from a gas to a liquid.' Condensation occurs when a gas cools and transforms into a liquid state. For example, when water vapor in the air cools and forms droplets, it is an example of condensation. This process is commonly observed in the formation of clouds or dew on grass in the early morning. Choice B is incorrect because it describes the process of vaporization rather than condensation. Choice C is incorrect as it refers to the process of melting. Choice D is incorrect as it describes sublimation, which is the transition from a solid to a gas without passing through the liquid phase.

4. Which of the following structures is found in the nucleus of a cell?

• A. Mitochondria
• B. Endoplasmic reticulum
• C. Chromosomes
• D. Ribosomes

Correct answer: C

Rationale: Chromosomes, which contain genetic information, are found in the nucleus of a cell. They play a crucial role in cell division, gene expression, and inheritance. Mitochondria, responsible for energy production, are located in the cytoplasm, not the nucleus. The endoplasmic reticulum is mainly involved in protein and lipid synthesis and is not a component of the nucleus. Ribosomes, essential for protein synthesis, are found in the cytoplasm and on the endoplasmic reticulum, but not in the nucleus.

5. Which type of muscle is found in the walls of hollow organs, such as the stomach and intestines, and is responsible for involuntary contractions to propel substances through the organs?

• A. Cardiac muscle
• B. Smooth muscle
• C. Skeletal muscle
• D. Striated muscle

Correct answer: B

Rationale: Smooth muscle is the correct answer. It is found in the walls of hollow organs like the stomach and intestines, where it performs involuntary contractions to move substances through these organs. Cardiac muscle, found in the heart, is responsible for pumping blood. Skeletal muscle is attached to bones and involved in voluntary movements. Striated muscle is a term often used interchangeably with skeletal muscle, which is responsible for voluntary movements but not typically found in the walls of hollow organs like the stomach and intestines.

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