Nursing Elites

1. What is the main function of red blood cells?

• A. Transport oxygen
• B. Transport carbon dioxide
• C. Regulate blood pressure
• D. Regulate heart rate

Correct answer: A

Rationale: The correct answer is A: Transport oxygen. Red blood cells are primarily responsible for carrying oxygen from the lungs to the tissues in the body. Hemoglobin, a protein found in red blood cells, binds to oxygen in the lungs and releases it to cells throughout the body. This oxygen transport is essential for cellular respiration and energy production in the body. Red blood cells do not regulate blood pressure or heart rate; their main role is oxygen transport. Choices B, C, and D are incorrect because red blood cells do not transport carbon dioxide, regulate blood pressure, or regulate heart rate. These functions are primarily carried out by other components of the circulatory and regulatory systems.

2. What is a characteristic feature of a convex lens?

• A. Converge light rays
• B. Diverge light rays
• C. Focus sound waves
• D. Create virtual images only

Correct answer: A

Rationale: A convex lens is characterized by its ability to converge light rays. The convex lens is thicker in the middle and thinner at the edges, causing light rays passing through it to converge or come together at a focal point on the opposite side of the lens. This convergence of light rays is what distinguishes convex lenses. Choice B is incorrect as convex lenses do not diverge light rays. Choice C is incorrect as convex lenses do not focus sound waves but rather light waves. Choice D is incorrect as convex lenses can create both real and virtual images, not just virtual images.

3. What is the principle behind optical fibers used in communication?

• A. Reflection of light within the fiber
• B. Refraction of light due to different densities within the fiber
• C. Total internal reflection guiding light through the fiber core
• D. Diffraction of light around bends in the fiber

Correct answer: C

Rationale: Optical fibers used in communication rely on the principle of total internal reflection guiding light through the fiber core. Total internal reflection occurs when light traveling through the core of the fiber is reflected back into the core due to the higher refractive index of the core compared to the cladding. This reflection ensures that the light remains confined within the core and propagates along the fiber without significant loss, allowing for efficient transmission of signals over long distances in optical communication systems. Choice A is incorrect because optical fibers do not primarily rely on simple reflection; instead, they utilize total internal reflection to guide light. Choice B is incorrect as the primary principle is not the refraction of light due to different densities within the fiber, but rather total internal reflection. Choice D is incorrect as diffraction is not the main principle behind optical fibers, which mainly rely on total internal reflection to guide light through the fiber core.

4. Which gland in the endocrine system is responsible for the production of red blood cells?

• A. Pituitary gland
• B. Thyroid gland
• C. Thymus gland
• D. None of the above

Correct answer: D

Rationale: Red blood cells are not produced by any of the glands listed in the options. Instead, red blood cells are produced in the bone marrow. The pituitary gland is known as the 'master gland' and controls several other endocrine glands but is not responsible for red blood cell production. The thyroid gland regulates metabolism and growth, not red blood cell production. The thymus gland is responsible for the production of T-cells, which are a type of white blood cell involved in the immune response. The parathyroid gland regulates calcium levels in the body, not red blood cell production. Therefore, none of the glands listed are responsible for the production of red blood cells.

5. Which of the following body systems controls fluid loss, protects deep tissues, and synthesizes vitamin D?

• A. The skeletal system
• B. The muscular system
• C. The lymphatic system
• D. The integumentary system

Correct answer: D

Rationale: The integumentary system is responsible for controlling fluid loss through sweat, protecting deep tissues as the body's first line of defense, and synthesizing vitamin D when exposed to sunlight. The skin, hair, nails, and associated glands make up the integumentary system, which plays a crucial role in maintaining homeostasis and overall health. The skeletal system (Choice A) provides structural support and protection for internal organs but does not directly control fluid loss, protect deep tissues, or synthesize vitamin D. The muscular system (Choice B) is responsible for movement and stability but is not involved in the functions described. The lymphatic system (Choice C) is primarily responsible for immunity and fluid balance, not the specific functions mentioned in the question.

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