Nursing Elites

1. Sebaceous glands, located in the dermis, secrete an oily substance called:

• A. Sweat
• B. Sebum
• C. Cerumen
• D. Mucus

Correct answer: B

Rationale: Sebaceous glands are responsible for secreting an oily substance called sebum, not sweat, cerumen, or mucus. Sebum plays a vital role in lubricating and waterproofing the skin and hair, preventing them from drying out. Sweat glands produce sweat to regulate body temperature. Cerumen is the medical term for earwax, produced by ceruminous glands in the ear canal, while mucus is a slimy substance that protects and lubricates body tissues. Therefore, the correct answer is B: Sebum, as it is the oily substance secreted by sebaceous glands.

2. Which of the following is NOT a function of the endoplasmic reticulum (ER)?

• A. Synthesis of lipids (fats)
• B. Transport of materials within the cell
• C. Detoxification of harmful substances
• D. Breakdown of cellular waste products

Correct answer: D

Rationale: The endoplasmic reticulum (ER) is not involved in the breakdown of cellular waste products; this function is primarily carried out by lysosomes. The ER is responsible for the synthesis of lipids (fats), transport of materials within the cell, and detoxification of harmful substances. Lysosomes are the organelles responsible for breaking down cellular waste products through processes like autophagy. Therefore, option D is the correct answer as it does not align with the known functions of the endoplasmic reticulum.

3. What is the formula for calculating density?

• A. Density = Volume / Mass
• B. Density = Mass × Volume
• C. Density = Mass / Volume
• D. Density = Volume - Mass

Correct answer: A

Rationale: Density is defined as the amount of mass in a given volume. The formula for calculating density is Density = Mass / Volume. This means that you divide the mass of an object by its volume to determine its density. Therefore, the correct formula for calculating density is Density = Volume / Mass. Choice A is correct because density is calculated by dividing the volume by the mass. Choices B, C, and D are incorrect because they do not represent the correct relationship between mass and volume in calculating density.

4. What is the role of platelets in the blood?

• A. Transport oxygen
• B. Fight infection
• C. Produce antibodies
• D. Clot blood

Correct answer: D

Rationale: Platelets play a crucial role in blood clotting by forming clots to help stop bleeding. While red blood cells transport oxygen, white blood cells fight infection, and immune cells produce antibodies, platelets specifically function to prevent excessive bleeding by forming clots. Therefore, the correct answer is D. Choices A, B, and C are incorrect as they describe functions of other components of the blood, not platelets.

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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