Nursing Elites

1. Which of the following is a component of the immune system?

• A. Red blood cells
• B. White blood cells
• C. Platelets
• D. Plasma

Correct answer: B

Rationale: White blood cells are a crucial component of the immune system as they play a key role in fighting infections and foreign invaders. Red blood cells are primarily involved in oxygen transport, platelets are important for blood clotting, and plasma is the liquid component of blood that carries various substances but is not directly involved in the immune response.

2. Which hormone, produced by the thyroid gland, plays a key role in regulating calcium levels in the blood by promoting calcium release from bones and increasing calcium reabsorption in the kidneys?

• A. Calcitonin
• B. Parathyroid hormone (PTH)
• C. Thyroxine
• D. Insulin

Correct answer: A

Rationale: Calcitonin, produced by the thyroid gland, is responsible for regulating calcium levels in the blood. It works by decreasing blood calcium levels through two main mechanisms: promoting calcium uptake by bones and decreasing calcium reabsorption in the kidneys. Parathyroid hormone (PTH), on the other hand, increases blood calcium levels by promoting calcium release from bones and increasing calcium absorption in the intestines. Thyroxine, another thyroid hormone, primarily regulates metabolism and has no direct influence on calcium levels. Insulin, produced by the pancreas, is involved in regulating blood sugar levels and is not related to calcium homeostasis.

3. During ejaculation, sperm travels through a tube from the testes to the urethra. What is the name of this tube?

• A. Vas deferens
• B. Epididymis
• C. Seminal vesicle
• D. Urethra

Correct answer: A

Rationale: The vas deferens is the correct answer. It is the tube that carries sperm from the testes to the urethra during ejaculation. The vas deferens plays a crucial role in transporting mature sperm for ejaculation. The epididymis is responsible for sperm maturation and storage, not the direct passage of sperm to the urethra. The seminal vesicle produces fluid that combines with sperm to form semen but is not the tube for sperm transport. The urethra serves as the passageway for both urine and semen out of the body but is not the specific tube that transports sperm from the testes to the urethra.

4. What are the three layers of the heart?

• A. Endocardium, myocardium, epicardium
• B. Pericardium, endocardium, myocardium
• C. Epicardium, myocardium, endocardium
• D. Pericardium, myocardium, endocardium

Correct answer: C

Rationale: The correct answer is C: Epicardium, myocardium, endocardium. The heart wall consists of three layers: the outer layer is the epicardium, the middle muscular layer is the myocardium, and the inner layer is the endocardium. Understanding the layers of the heart is essential for comprehending its structure and function. Choices A, B, and D are incorrect because they do not present the layers of the heart in the correct order. The pericardium is the outermost layer that surrounds the heart, but it is not part of the heart wall itself. Therefore, choices B and D are incorrect. Choice A is incorrect as it presents the layers in the wrong order, starting with the endocardium instead of the epicardium, which is the outermost layer.

5. What controls muscles by sending electrical impulses to the muscles?

• A. Blood vessels
• B. Nerves
• C. Hormones
• D. Neurons

Correct answer: B

Rationale: Nerves control muscles by transmitting electrical impulses that initiate muscle contractions. Blood vessels are responsible for transporting blood, not controlling muscles. Hormones are chemical messengers produced by glands to regulate bodily functions, not specifically controlling muscles. Neurons are the basic building blocks of the nervous system that transmit signals, but nerves are the specific structures that control muscles by sending electrical impulses.

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