Nursing Elites

1. Which of the following is not a component of the central nervous system?

• A. Brain
• B. Heart
• C. Retina
• D. Spinal cord

Correct answer: B

Rationale: The central nervous system comprises the brain and spinal cord, responsible for processing and transmitting information. The retina, though part of the eye, is an extension of the central nervous system. However, the heart is part of the circulatory system, responsible for pumping blood throughout the body. Therefore, the correct answer is the heart as it is not a component of the central nervous system.

2. What is the primary function of hemoglobin in red blood cells?

• A. To transport nutrients
• B. To fight infections
• C. To carry oxygen
• D. To produce energy

Correct answer: C

Rationale: The correct answer is C: 'To carry oxygen.' Hemoglobin in red blood cells binds to oxygen in the lungs and transports it to the tissues and organs throughout the body. This oxygen transport is crucial for cellular respiration and the overall functioning of the body. Choices A, B, and D are incorrect because hemoglobin's primary function is not to transport nutrients, fight infections, or produce energy in red blood cells.

3. What is the primary function of the alveoli in the lungs?

• A. Removing carbon dioxide from the blood
• B. Exchanging oxygen and carbon dioxide
• C. Transporting oxygen to the bloodstream
• D. Filtering blood

Correct answer: B

Rationale: The primary function of the alveoli in the lungs is to exchange oxygen and carbon dioxide. The alveoli are tiny air sacs in the lungs responsible for this gas exchange during breathing. Oxygen diffuses from the inhaled air into the blood in the capillaries surrounding the alveoli, while carbon dioxide diffuses from the blood into the alveoli to be exhaled out of the body. Choice A is incorrect because the alveoli primarily facilitate the exchange of gases, not just the removal of carbon dioxide. Choice C is incorrect as the alveoli do not transport oxygen to the bloodstream but rather facilitate the exchange of gases. Choice D is incorrect as the alveoli are not involved in filtering blood but in gas exchange to ensure proper oxygenation and removal of carbon dioxide in the respiratory process.

4. Which part of the brain controls breathing and heart rate?

• A. Cerebrum
• B. Medulla oblongata
• C. Cerebellum
• D. Hypothalamus

Correct answer: B

Rationale: The medulla oblongata, located in the brainstem, plays a crucial role in controlling vital functions such as breathing, heart rate, and blood pressure. It serves as the control center for automatic functions necessary for survival, making it the correct choice in this scenario. The cerebrum is responsible for higher brain functions like thinking and voluntary movements, so it does not control basic physiological functions like breathing and heart rate. The cerebellum is mainly involved in coordination and balance, while the hypothalamus regulates body temperature, hunger, and thirst, but not specifically breathing and heart rate.

5. Where are B-lymphocytes produced?

• A. Thymus
• B. Red bone marrow
• C. Lymph nodes
• D. Spleen

Correct answer: B

Rationale: B-lymphocytes are produced in the red bone marrow. The red bone marrow is the primary site for B-cell development, where they mature before entering the circulation. The thymus is responsible for T-lymphocyte maturation, not B-lymphocytes. Lymph nodes and spleen play roles in immune responses but are not the primary sites for B-lymphocyte production.

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