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 role of the spleen in the body?

• A. To produce bile
• B. To filter blood and remove old red blood cells
• C. To produce red blood cells
• D. To store fat

Correct answer: B

Rationale: The correct answer is B. The spleen acts as a blood filter, removing old or damaged red blood cells. It also plays a role in immune responses, storing blood reserves, and helping to fight infection. The production of bile is primarily associated with the liver, not the spleen. While the bone marrow is responsible for red blood cell production, the spleen's main functions do not include this process. Storing fat is not a primary function of the spleen.

3. What does the term 'dilution' refer to in a solution?

• A. Adding more solvent to decrease concentration
• B. Adding more solute to increase concentration
• C. Reducing the temperature to increase solubility
• D. Increasing pressure to increase solubility

Correct answer: A

Rationale: The term 'dilution' in a solution refers to adding more solvent to decrease the concentration of the solution. Dilution involves reducing the concentration of the solute in the solution by increasing the amount of solvent. Choice B is incorrect because adding more solute would increase the concentration, not decrease it. Choices C and D are also incorrect as they relate to factors affecting solubility, not dilution specifically. Therefore, choice A is the correct answer as it accurately defines the process of dilution in a solution.

4. What is the main function of the nervous system?

• A. To fight infection
• B. To control body movement and coordination
• C. To regulate metabolism
• D. To transport oxygen

Correct answer: B

Rationale: The main function of the nervous system is to control body movement and coordination by transmitting signals between different parts of the body. Choice A is incorrect because the immune system, not the nervous system, is primarily responsible for fighting infections. Choice C is incorrect as regulating metabolism is primarily handled by the endocrine system. Choice D is incorrect because the transportation of oxygen is mainly the function of the circulatory system, specifically the blood.

5. What is the primary mode of CO2 transport in the body?

• A. Bicarbonate
• B. Carbamino compounds
• C. None of these
• D. Plasma

Correct answer: A

Rationale: The correct answer is A: Bicarbonate. In the body, the primary mode of CO2 transport is as bicarbonate. Carbon dioxide is converted to bicarbonate in red blood cells as part of the bicarbonate buffer system, which helps maintain the pH balance in the blood. Bicarbonate is then transported in the plasma to the lungs where it is converted back to carbon dioxide for exhalation. While carbamino compounds also play a role in CO2 transport by binding to amino groups on proteins, bicarbonate is the main mode of transport for carbon dioxide in the body. Options B, C, and D are incorrect as they do not represent the primary mechanism of CO2 transport in the body.

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