Nursing Elites

1. Which of the following structures prevents food from entering the windpipe?

• A. Pharynx
• B. Esophagus
• C. Larynx
• D. Epiglottis

Correct answer: D

Rationale: The epiglottis is the structure that prevents food from entering the windpipe by covering the trachea during swallowing. When food is swallowed, the epiglottis folds over the opening of the trachea to ensure that food goes down the esophagus and not into the airway. The pharynx is a shared pathway for both food and air, leading to the esophagus and larynx respectively. The esophagus is the muscular tube that carries food from the throat to the stomach. The larynx is responsible for producing sound and protecting the airway during swallowing, but the epiglottis is specifically designed to prevent food from entering the windpipe.

2. If the pressure in the pulmonary artery is increased above normal, which chamber of the heart will be affected first?

• A. The right atrium
• B. The left atrium
• C. The right ventricle
• D. The left ventricle

Correct answer: C

Rationale: When the pressure in the pulmonary artery is increased above normal, the right ventricle of the heart will be affected first. The right ventricle is responsible for pumping blood into the pulmonary artery, which carries deoxygenated blood to the lungs for oxygenation. Increased pressure in the pulmonary artery can result in increased workload on the right ventricle as it tries to pump blood against higher resistance, leading to potential strain and dysfunction in the right ventricle. Choices A, B, and D are incorrect because the right ventricle is the chamber directly connected to the pulmonary artery, and it bears the immediate impact of any changes in pressure within this artery. The right atrium receives deoxygenated blood from the body and the left atrium receives oxygenated blood from the lungs, while the left ventricle pumps oxygenated blood to the body and the right ventricle pumps deoxygenated blood to the lungs.

3. What is the term for a microorganism that lives on or in the human body and normally causes no disease or harm?

• A. Bacteria
• B. Commensal Microorganism
• C. Microorganism
• D. Host

Correct answer: B

Rationale: The correct term for a microorganism that lives on or in the human body without causing harm is a commensal microorganism. Commensal microorganisms coexist with the host without causing disease or harm. Choice A, 'Bacteria,' is too broad as not all bacteria are harmless in the body. Choice C, 'Microorganism,' is a general term and does not specifically refer to the harmless nature of the organism. Choice D, 'Host,' refers to the organism harboring the microorganism, not the microorganism itself.

4. When a certain plant is introduced into an area, and the population of a certain insect species declines, what can be concluded from this?

• A. The plant is toxic to the insect in question.
• B. The plant competes with and drives out plants that the insect feeds on.
• C. The insect population was declining anyway; the fact that it happened when the plant was introduced is a coincidence.
• D. All of these explanations may be possible; further investigation is necessary to determine which is true.

Correct answer: D

Rationale: The given scenario presents multiple possible explanations for the decline in the insect population with the introduction of a particular plant. It could be due to the plant being toxic to the insect (Option A), competing with and driving out plants that the insect feeds on (Option B), or the decline could be coincidental with the plant introduction as the insect population was already decreasing (Option C). Without further investigation and evidence, it is not possible to definitively determine which explanation is correct. Therefore, all of these possibilities may be true, and thorough investigation is necessary to reach a conclusive conclusion.

5. When a car brakes to a stop, friction between the tires and the road acts as:

• A. A balanced force
• B. An unbalanced force causing deceleration
• C. An unbalanced force causing the car to remain at rest
• D. No force at all

Correct answer: B

Rationale: When a car brakes to a stop, friction between the tires and the road acts as an unbalanced force causing deceleration. This friction force opposes the motion of the car, resulting in a decrease in speed until the car comes to a complete stop. Choice A is incorrect because if the forces were balanced, the car would not experience any deceleration. Choice C is incorrect because if the force were unbalanced in the direction of motion, the car would continue to move instead of coming to a stop. Choice D is incorrect because friction between the tires and the road does exert a force, causing deceleration.

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