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. Vacuoles are large sacs for storage in plant cells. What is their main function in animal cells?

• A. Protein synthesis
• B. Waste storage and disposal
• C. Photosynthesis
• D. Cellular respiration

Correct answer: B

Rationale: Vacuoles in animal cells primarily function in waste storage and disposal, helping to maintain cellular homeostasis by storing waste products and aiding in their removal from the cell. Unlike plant cells, animal cells do not typically use vacuoles for storage purposes such as water, nutrients, or pigments. Instead, animal cells rely on other organelles like lysosomes for waste management and maintaining cellular balance. Choices A, C, and D are incorrect because protein synthesis occurs in ribosomes, photosynthesis takes place in chloroplasts (absent in animal cells), and cellular respiration mainly occurs in mitochondria, respectively. Vacuoles in animal cells serve a different purpose compared to plant cells.

3. Which of the following is an example of a commensal relationship between a microorganism and a human?

• A. Salmonella causing food poisoning
• B. taphylococcus aureus causing skin infections
• C. coli living in the gut
• D. Rabies virus causing neurological disease

Correct answer: C

Rationale: A commensal relationship is a type of symbiotic relationship in which one organism benefits, while the other is neither harmed nor benefited. In this case, E. coli living in the gut is an example of a commensal relationship because it can benefit from the environment in the gut without causing harm to the human host. Option A, Salmonella causing food poisoning, is an example of a pathogenic relationship where the microorganism causes harm to the host. Option B, Staphylococcus aureus causing skin infections, is also an example of a pathogenic relationship where the microorganism causes harm to the host. Option D, Rabies virus causing neurological disease, is another example of a pathogenic relationship where the microorganism causes harm to the host.

4. Which of the following best defines the anatomical term medial?

• A. Being face down
• B. On the front of the body or limb
• C. Near to the midline of the body
• D. Above or on top of the lungs

Correct answer: C

Rationale: The correct definition of the anatomical term 'medial' is being close or near to the midline of the body. This term describes a position closer to the center or midline of the body, opposite to 'lateral' which refers to a position further away from the midline. Choice A, 'Being face down,' is incorrect as it describes the anatomical term 'prone.' Choice B, 'On the front of the body or limb,' is incorrect as it describes the anatomical term 'anterior.' Choice D, 'Above or on top of the lungs,' is incorrect as it does not relate to the term 'medial.'

5. What is the primary function of the coronary arteries in the cardiovascular system?

• A. Carry oxygenated blood to the heart muscle
• B. Carry deoxygenated blood from the heart muscle
• C. Pump blood to the lungs for oxygenation
• D. Regulate blood pressure in the systemic circulation

Correct answer: A

Rationale: The primary function of the coronary arteries is to carry oxygenated blood to the heart muscle. Oxygenated blood is crucial for providing nutrients and oxygen to the heart muscle cells, enabling the heart to work efficiently. Without this oxygenated blood supply, the heart muscle may not receive the required nutrients and oxygen, potentially resulting in heart damage or dysfunction. Choices B, C, and D are incorrect as coronary arteries do not carry deoxygenated blood from the heart muscle, pump blood to the lungs for oxygenation, or regulate blood pressure in the systemic circulation. The coronary arteries specifically supply oxygenated blood to the heart muscle to support its function and vitality.

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