Nursing Elites

1. Why is the lining of the stomach covered with rugae?

• A. Rugae increase the output of gastric juices.
• B. Rugae increase the surface area of the stomach.
• C. Rugae increase the permeability of the stomach walls.
• D. Rugae increase the types of nutrients that can diffuse.

Correct answer: B

Rationale: Rugae are folds in the stomach lining that increase its surface area. This increased surface area allows for more efficient digestion and absorption of nutrients in the stomach. Choice A is incorrect because rugae do not directly affect the output of gastric juices. Choice C is incorrect because rugae do not impact the permeability of the stomach walls. Choice D is incorrect because rugae do not influence the types of nutrients that can diffuse.

2. Which of the following structures is responsible for preventing the backflow of blood from the left ventricle into the left atrium?

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

Correct answer: D

Rationale: The correct answer is D, the Mitral valve. The mitral valve, also known as the bicuspid valve, is situated between the left atrium and the left ventricle. Its primary function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The other choices are incorrect because: A) The aortic valve prevents backflow from the aorta into the left ventricle. B) The pulmonary valve prevents backflow from the pulmonary artery into the right ventricle. C) The tricuspid valve prevents backflow from the right ventricle into the right atrium.

3. Which of the following is the main organ responsible for absorbing nutrients?

• A. Stomach
• B. Small intestine
• C. Large intestine
• D. Pancreas

Correct answer: B

Rationale: The small intestine is the main organ responsible for absorbing nutrients from the food we eat. It is where the majority of digestion and absorption of nutrients such as carbohydrates, proteins, fats, vitamins, and minerals occurs. The inner lining of the small intestine is covered in tiny finger-like projections called villi, which increase the surface area available for nutrient absorption. While the stomach plays a role in breaking down food into smaller particles, the actual absorption of nutrients primarily takes place in the small intestine. The large intestine mainly absorbs water and electrolytes, and the pancreas produces digestive enzymes and hormones but is not primarily responsible for absorbing nutrients.

4. Why are negative feedback mechanisms crucial in the endocrine system?

• A. To increase hormone production continuously
• B. To maintain hormone levels within a specific range
• C. To cause a constant release of hormones
• D. To disrupt communication between glands

Correct answer: B

Rationale: Negative feedback mechanisms in the endocrine system play a vital role in maintaining hormone levels within a specific range. When hormone levels deviate from the set point, negative feedback signals prompt adjustments in hormone production to bring the levels back to the optimal range. This process ensures a delicate balance of hormones in the body, preventing excesses or deficiencies. Choice A is incorrect because continuously increasing hormone production would lead to imbalances. Choice C is incorrect as a constant release of hormones without regulation would disrupt homeostasis. Choice D is incorrect because disrupting communication between glands would hinder proper coordination and regulation of hormone levels, which is essential for the body's overall function.

5. Which macromolecules are composed of nucleotides and store information and energy?

• A. Lipids
• B. Proteins
• C. Carbohydrates
• D. Nucleic acids

Correct answer: D

Rationale: The correct answer is D: Nucleic acids. Nucleic acids, such as DNA and RNA, are composed of nucleotides and are responsible for storing genetic information and energy (e.g., ATP). Lipids, proteins, and carbohydrates are distinct macromolecules with varying functions and structures. Lipids primarily serve as energy reservoirs, structural components, and cell signaling molecules. Proteins play crucial roles in cellular functions like enzyme activity, structural support, and intracellular signaling. Carbohydrates are mainly utilized as an energy source and for structural purposes within cells.

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