Nursing Elites

1. A symbiotic relationship where one organism benefits and the other is not harmed is called:

• A. Mutualism
• B. Commensalism
• C. Parasitism
• D. Predation

Correct answer: B

Rationale: B) Commensalism: In commensalism, one organism benefits while the other is neither helped nor harmed. This is the relationship described in the question. The correct answer is Commensalism because it specifically fits the scenario where one organism benefits without affecting the other. A) Mutualism: In mutualism, both organisms involved benefit from the relationship. C) Parasitism: In parasitism, one organism benefits at the expense of the other organism, which is harmed. D) Predation: In predation, one organism (predator) kills and consumes another organism (prey) for food.

2. Which of the following terms refers to the degeneration of nerve tissue?

• A. Potentiation
• B. Demyelination
• C. Reuptake
• D. Neurogenesis

Correct answer: B

Rationale: Demyelination specifically refers to the degeneration of the myelin sheath that covers nerve fibers. When demyelination occurs, nerve function and communication can be impaired. Potentiation involves the strengthening of synaptic connections, reuptake is the reabsorption process of neurotransmitters by the presynaptic neuron, and neurogenesis is the generation of new neurons. Therefore, the correct term for the degeneration of nerve tissue among the options provided is demyelination.

3. Which property of a substance refers to its ability to undergo a chemical change and form new substances?

• A. Density
• B. Mass
• C. Reactivity
• D. Volume

Correct answer: C

Rationale: Reactivity is the property of a substance that describes its ability to undergo a chemical change and form new substances through chemical reactions. Density, mass, and volume are physical properties of a substance and do not directly relate to its ability to undergo chemical changes. Density is the mass of a substance per unit volume, mass is the amount of matter present, and volume is the amount of space occupied by the substance. Reactivity specifically deals with how likely a substance is to engage in chemical reactions. Therefore, the correct answer is C - Reactivity.

4. Which of the following is NOT a function of the skeletal system?

• A. Support and structure
• B. Production of red blood cells
• C. Storage of minerals like calcium
• D. Insulation of the body

Correct answer: D

Rationale: The skeletal system's primary functions include support and structure, protection of internal organs, movement facilitation, production of blood cells, and storage of minerals like calcium. Insulation of the body is not a function of the skeletal system. Insulation, typically involving fat under the skin, helps regulate body temperature but is not a direct function of the skeletal system. Choice B, the production of red blood cells, is a function of the skeletal system as it occurs in the bone marrow within the bones. Choices A and C are also correct functions of the skeletal system.

5. What is the primary function of the pyloric sphincter?

• A. to regulate the movement of food material from the stomach to the duodenum
• B. to neutralize stomach acid
• C. to prevent digested food materials and stomach acid from entering the esophagus
• D. to begin the process of chemical digestion

Correct answer: A

Rationale: The primary function of the pyloric sphincter is to regulate the flow of partially digested food material (chyme) from the stomach into the small intestine, specifically the duodenum. This control is essential for proper digestion and absorption of nutrients in the small intestine. Choices B, C, and D are incorrect. Choice B is incorrect because neutralizing stomach acid is primarily the function of the stomach lining and antacid mechanisms. Choice C is incorrect because preventing the backflow of digested food materials and stomach acid into the esophagus is mainly the role of the lower esophageal sphincter. Choice D is incorrect because the chemical digestion process primarily starts in the stomach through the action of gastric juices, not the pyloric sphincter.

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