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 are the three main types of muscle tissue in the human body?

• A. Smooth, cardiac, and voluntary skeletal
• B. Smooth, skeletal, and involuntary cardiac
• C. Voluntary smooth, cardiac, and skeletal
• D. Striated, non-striated, and epithelial

Correct answer: A

Rationale: The three main types of muscle tissue in the human body are smooth muscle (involuntary), cardiac muscle (involuntary), and voluntary skeletal muscle. Smooth muscle is found in the walls of hollow organs, cardiac muscle is found in the heart, and skeletal muscle is attached to bones and is under voluntary control. Option A correctly identifies these three main types of muscle tissue in the human body. Choice B is incorrect because it lists skeletal muscle as involuntary, which is not accurate. Choice C is incorrect because it lists voluntary smooth muscle, which does not exist as smooth muscle is involuntary. Choice D is incorrect because it uses terms like striated, non-striated, and epithelial, which are not the main types of muscle tissue but rather descriptions related to muscle characteristics and location.

3. Which brain area can lead to difficulty with language and speech if damaged?

• A. Broca's area
• B. Wernicke's area
• C. Occipital lobe
• D. Cerebellum

Correct answer: A

Rationale: Damage to Broca's area, located in the frontal lobe of the brain, can result in difficulties with language and speech production. Broca's area is responsible for speech production and coordinating the muscles involved in speech. Damage to this area can lead to Broca's aphasia, characterized by struggles in forming words and sentences. On the other hand, damage to Wernicke's area in the temporal lobe can cause issues with language comprehension and producing meaningful language, leading to Wernicke's aphasia. The occipital lobe primarily processes visual information, while the cerebellum is responsible for coordinating movement and balance, not language and speech.

4. Which of the following salt solutions is most likely to conduct electricity well?

• A. A saturated solution
• B. A concentrated solution of a strong electrolyte
• C. A dilute solution of a weak acid
• D. A mixture of a neutral compound and water

Correct answer: B

Rationale: A concentrated solution of a strong electrolyte is most likely to conduct electricity well. Strong electrolytes completely dissociate into ions in solution, allowing for the flow of electric current. This high concentration of ions in the solution enhances its conductivity, making it a better conductor compared to other options. A saturated solution, although containing dissolved ions, may not have a high enough concentration to conduct electricity effectively. A dilute solution of a weak acid is a poor conductor as weak acids only partially dissociate into ions. A mixture of a neutral compound and water does not contain free ions necessary for conducting electricity.

5. What is the study of the geographical distribution of organisms and the factors that influence it known as?

• A. Paleontology (the study of fossils)
• B. Taxonomy (the classification of organisms)
• C. Biogeography
• D. Population genetics

Correct answer: C

Rationale: Biogeography is the scientific discipline that focuses on studying the geographical distribution of organisms and the factors that influence their patterns of distribution. This field investigates the reasons behind why species are located where they are, taking into account historical events, ecological interactions, and physical geography. Paleontology (option A) specifically deals with the study of fossils and the history of life on Earth, mainly focusing on extinct organisms. Taxonomy (option B) is the science that involves classifying and naming organisms based on their characteristics. Population genetics (option D) is concerned with the study of genetic variation and evolutionary processes within populations of organisms. Therefore, in the context of studying the distribution of organisms across space and time, biogeography is the most appropriate choice.

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