Nursing Elites

1. 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.

2. Which of the following is a characteristic of an interneuron?

• A. Forms neural circuits
• B. Interacts with effectors
• C. Sends impulses to the CNS
• D. Functions as an efferent nerve cell

Correct answer: A

Rationale: The correct characteristic of an interneuron is that it forms neural circuits, connecting sensory and motor neurons within the central nervous system. Interneurons facilitate communication between different neurons in the central nervous system, helping in the processing and integration of signals. Choice B is incorrect as interneurons primarily interact with other neurons, not effectors. Choice C is incorrect as interneurons typically do not send impulses to the CNS; they operate within the CNS. Choice D is incorrect as interneurons are not efferent nerve cells; they are mainly involved in processing signals within the CNS rather than transmitting signals to effectors.

3. Which of the following is an example of a flat bone?

• A. Femur
• B. Scapula
• C. Humerus
• D. Tibia

Correct answer: B

Rationale: The correct answer is B, the Scapula. Flat bones, such as the scapula, are thin, flattened bones that provide protection to internal organs and serve as attachment points for muscles. The other choices, femur, humerus, and tibia, are examples of long bones, which are characterized by their elongated structure and are primarily involved in supporting weight and facilitating movement.

4. Antigenic variation, a common strategy used by some viruses, allows them to:

• A. Produce toxins
• B. Evade the immune system
• C. Survive outside a host
• D. Replicate rapidly

Correct answer: B

Rationale: Antigenic variation is a strategy used by some viruses to evade the host's immune response. By constantly changing their surface antigens, viruses can avoid recognition and destruction by the immune system. This allows the virus to persist in the host and continue replicating, leading to prolonged infection and potential transmission to other hosts. Antigenic variation does not directly involve the production of toxins, survival outside a host, or rapid replication, making options A, C, and D incorrect in this context.

5. From which of the following germ layers does the nervous system develop?

• A. Ectoderm
• B. Endoderm
• C. Gastroderm
• D. Mesoderm

Correct answer: A

Rationale: The correct answer is A: Ectoderm. The nervous system develops from the ectoderm, which is the outermost of the three germ layers. The ectoderm gives rise to structures such as the skin, hair, nails, and the entire nervous system. Choices B, C, and D are incorrect because the endoderm gives rise to the lining of the gut and associated organs, the gastroderm is not a recognized germ layer, and the mesoderm forms structures like muscles, bones, blood, and the circulatory system, but not the nervous system.

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