Nursing Elites

1. Which of the following neurotransmitters slows down the activity of neurons, preventing them from becoming overexcited?

• A. Acetylcholine
• B. Dopamine
• C. GABA
• D. Serotonin

Correct answer: C

Rationale: The correct answer is C: GABA (gamma-aminobutyric acid). GABA acts as an inhibitory neurotransmitter that reduces neuronal activity, thus preventing overexcitation. Acetylcholine (choice A) is involved in muscle control and cognitive function, but it is not primarily responsible for slowing down neuronal activity. Dopamine (choice B) plays a role in reward-motivated behavior and motor control, rather than inhibiting neuronal firing. Serotonin (choice D) is involved in mood regulation, sleep, and appetite but does not primarily slow down neuronal activity to prevent overexcitation.

2. What is the difference between exhalation (expiration) and inhalation (inspiration)?

• A. Exhalation involves active muscle contraction, while inhalation is passive.
• B. Inhalation brings in oxygen-rich air, while exhalation releases carbon dioxide-rich air.
• C. Exhalation occurs through the nose only, while inhalation can occur through the nose or mouth.
• D. Inhalation warms and humidifies air, while exhalation cools and dries air.

Correct answer: A

Rationale: Exhalation (expiration) involves active muscle contraction, specifically the diaphragm and intercostal muscles, to decrease the volume of the thoracic cavity and push air out of the lungs. In contrast, inhalation (inspiration) is a passive process where the diaphragm and external intercostal muscles contract to increase the thoracic cavity volume, allowing air to flow into the lungs. Choice B is incorrect as exhalation removes carbon dioxide-rich air and inhalation brings in oxygen-rich air. Choice C is incorrect because both exhalation and inhalation can occur through the nose or mouth. Choice D is inaccurate as inhalation humidifies and warms the air, while exhalation cools and dries it.

3. In nuclear physics, the term 'magic number' refers to specific numbers of protons or neutrons that contribute to:

• A. Increased nuclear instability
• B. Enhanced radioactive decay rates
• C. Exceptional stability of the nucleus
• D. All of the above

Correct answer: C

Rationale: In nuclear physics, the term 'magic number' refers to specific numbers of protons or neutrons that lead to exceptional stability of the nucleus. These 'magic numbers' correspond to completely filled nuclear energy levels, resulting in increased stability rather than instability. Choice A, 'Increased nuclear instability,' is incorrect as magic numbers actually contribute to stability. Choice B, 'Enhanced radioactive decay rates,' is also incorrect as magic numbers do not affect decay rates but rather stability. Therefore, the correct answer is choice C, as magic numbers contribute to the exceptional stability of the nucleus.

4. What is the primary function of platelets in the blood?

• A. To carry oxygen
• B. To clot blood
• C. To fight infection
• D. To transport nutrients

Correct answer: B

Rationale: The correct answer is B: 'To clot blood.' Platelets play a crucial role in the clotting process, forming a plug at the site of blood vessel injury to prevent excessive bleeding. While red blood cells carry oxygen, white blood cells fight infection, and nutrients are transported by plasma, platelets are specifically responsible for blood clotting. Choice A is incorrect because red blood cells are responsible for carrying oxygen. Choice C is incorrect because white blood cells are primarily involved in fighting infection. Choice D is incorrect as the transport of nutrients is mainly carried out by plasma, not platelets.

5. Which of the following statements accurately characterizes the relationship between genes and chromosomes?

• A. Each gene contains multiple chromosomes.
• B. Each chromosome contains multiple genes.
• C. Genes and chromosomes are two different things referring to the same entity.
• D. Genes and chromosomes are not interchangeable terms and do not always occur in equal numbers.

Correct answer: B

Rationale: The correct answer is B: Each chromosome contains multiple genes. Genes, which are segments of DNA, are located on chromosomes and carry hereditary information. Chromosomes contain many genes, indicating that genes are part of the structure of chromosomes. Choice A is incorrect because genes do not contain chromosomes; rather, they are located on chromosomes. Choice C is incorrect as genes and chromosomes are distinct entities with different functions. Choice D is incorrect because genes and chromosomes are related but not in equal numbers; chromosomes contain multiple genes, but the number of genes can vary between chromosomes.

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