Nursing Elites

1. How does sunscreen protect the skin from harmful ultraviolet (UV) rays?

• A. By reflecting UV rays away from the skin
• B. By absorbing UV rays and converting them to heat
• C. By blocking UV rays completely
• D. By stimulating melanin production

Correct answer: B

Rationale: Sunscreen works by absorbing UV rays and converting them to heat. This mechanism helps to prevent the UV rays from penetrating the skin and causing damage such as sunburn, premature aging, and skin cancer. Reflecting UV rays away from the skin (option A) is not the primary function of sunscreen. While sunscreen does block UV rays, it does not do so completely (option C) as some UV rays may still penetrate the skin. Sunscreen does not stimulate melanin production (option D) as a means of protecting the skin from UV rays.

2. Which plane divides the body into superior (top) and inferior (bottom) halves?

• A. Sagittal/Median Plane
• B. Frontal/Coronal Plane
• C. Transverse/Cross-Section Plane
• D. Horizontal Plane

Correct answer: C

Rationale: The Transverse or Cross-Section Plane is the correct answer as it divides the body into superior (top) and inferior (bottom) halves. This plane runs horizontally across the body, perpendicular to the long axis, separating the body into upper and lower sections. Choice A, the Sagittal/Median Plane, divides the body into left and right halves, not superior and inferior halves. Choice B, the Frontal/Coronal Plane, divides the body into anterior (front) and posterior (back) halves. Choice D, the Horizontal Plane, is not a standard anatomical plane used to divide the body into specific sections.

3. Which of the following is responsible for maintaining the body's circadian rhythm?

• A. Thyroid gland
• B. Pineal gland
• C. Pancreas
• D. Hypothalamus

Correct answer: B

Rationale: The pineal gland is responsible for maintaining the body's circadian rhythm by producing melatonin. Melatonin is a hormone that helps regulate the sleep-wake cycle and is essential in controlling the body's internal clock. The thyroid gland, although important for metabolism, is not directly involved in regulating circadian rhythms. The pancreas plays a role in blood sugar regulation through insulin production, not in controlling circadian rhythms. The hypothalamus is involved in regulating various bodily functions, but the pineal gland is specifically responsible for the circadian rhythm.

4. How does an unbalanced force affect an object at rest?

• A. It maintains the object's state of rest
• B. It does not affect the object's rest
• C. It moves the object into motion
• D. It decreases the object's mass

Correct answer: C

Rationale: An unbalanced force acting on an object at rest will cause the object to move into motion. This is in accordance with Newton's first law of motion, which states that an object at rest will remain at rest unless acted upon by an external force. Therefore, option C, 'It moves the object into motion,' is the correct answer. Choices A and B are incorrect because an unbalanced force disrupts the object's state of rest. Choice D is incorrect as force does not affect the mass of an object.

5. Which valve prevents blood from entering the left atrium when the ventricles contract?

• A. Pulmonary valve
• B. Tricuspid valve
• C. Mitral valve
• D. Aortic valve

Correct answer: C

Rationale: The correct answer is the mitral valve, also known as the bicuspid valve. The mitral valve prevents blood from flowing back into the left atrium during ventricular contraction. The tricuspid valve is located between the right atrium and right ventricle, the pulmonary valve is between the right ventricle and the pulmonary artery, and the aortic valve is situated between the left ventricle and the aorta. Therefore, choices A, B, and D are incorrect as they are not related to preventing blood from entering the left atrium during ventricular contraction.

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