Nursing Elites

1. What is the primary function of tight junctions, specialized regions between animal cells?

• A. Communication between cells
• B. Anchorage between cells
• C. Selective passage of materials
• D. All of the above

Correct answer: C

Rationale: The correct answer is C: Selective passage of materials. Tight junctions act as specialized structures between animal cells that create a barrier to the passage of materials. Their primary function is to prevent the leakage of extracellular fluid and control the selective passage of molecules between cells. This selective control is crucial in regulating the movement of substances across cell layers. Tight junctions do not directly facilitate communication between cells or provide anchorage between cells, as their main role is to regulate the passage of materials. Choices A and B are incorrect as tight junctions do not primarily serve for communication or anchorage between cells.

2. Which of the following is NOT a function of the integumentary system?

• A. Regulation of body temperature
• B. Protection from pathogens
• C. Synthesis of vitamin D
• D. Production of digestive enzymes

Correct answer: D

Rationale: The correct answer is D. The production of digestive enzymes is not a function of the integumentary system. The integumentary system is responsible for regulating body temperature, protecting the body from pathogens, and synthesizing vitamin D. Digestive enzymes are produced by organs in the digestive system, such as the pancreas and stomach, and not by the integumentary system.

3. The transfer of energy through feeding relationships in an ecosystem is called a:

• A. Food Chain
• B. Food Web
• C. Habitat
• D. Biome

Correct answer: A

Rationale: A food chain is a linear sequence of organisms where each organism consumes the one below it and is consumed by the one above it. This transfer of energy through feeding relationships is a fundamental concept in ecology to understand how energy flows through an ecosystem. In a food chain, energy is transferred from producers (plants) to primary consumers (herbivores), then to secondary consumers (carnivores), and so on. Each step in the food chain represents a trophic level, and energy is lost as heat at each level, resulting in a pyramid-shaped energy flow. Food webs, on the other hand, represent a more complex network of interconnected food chains within an ecosystem. Habitats refer to the specific environments where organisms live, and biomes are large geographical areas characterized by specific climates and vegetation types. Therefore, the correct answer is 'Food Chain' as it specifically describes the linear transfer of energy through feeding relationships in an ecosystem.

4. What is the action of the triceps reflex?

• A. Forces contraction of the triceps and extension of the arm.
• B. Forces contraction of the biceps, relaxation of the biceps, and arm extension.
• C. Causes the triceps to contract, causing the forearm to supinate and flex.
• D. Causes the triceps to relax and the upper arm to pronate and extend.

Correct answer: A

Rationale: The triceps reflex causes the triceps muscle to contract, leading to the extension of the arm. This reflex is a protective response to sudden stretching of the triceps muscle, as seen when a physician taps the triceps tendon during a physical examination. Choice A is the correct answer as it accurately reflects the action of the triceps reflex. Choices B, C, and D are incorrect because they describe actions that are not associated with the triceps reflex. Biceps contraction, forearm supination, flexion, triceps relaxation, and pronation are not part of the triceps reflex arc.

5. Which type of muscle is under voluntary control?

• A. Smooth muscle
• B. Cardiac muscle
• C. Skeletal muscle
• D. Involuntary muscle

Correct answer: C

Rationale: The correct answer is C: Skeletal muscle. Skeletal muscle is under voluntary control, allowing for conscious movement of the body. Smooth muscle and cardiac muscle are both types of involuntary muscles that are not under conscious control. Smooth muscle is found in the walls of internal organs and blood vessels, functioning involuntarily. Cardiac muscle makes up the heart and contracts involuntarily to pump blood. Involuntary muscle (choice D) is a general term that encompasses smooth muscle and cardiac muscle, which operate involuntarily throughout the body.

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