Nursing Elites

1. Unlike the circulatory system, the lymphatic system does not have a pump. How does lymph move through the lymphatic vessels?

• A. By the pumping action of the heart
• B. Due to muscle contractions and breathing movements
• C. Through one-way valves within the vessels
• D. All of the above

Correct answer: C

Rationale: Lymph moves through the lymphatic vessels primarily due to muscle contractions and breathing movements and also with the help of one-way valves within the vessels. The lymphatic system lacks a central pump like the heart; hence, it relies on the contraction of surrounding muscles and breathing movements to propel lymph fluid. One-way valves within the lymphatic vessels prevent backflow and ensure the unidirectional flow of lymph. Option A is incorrect as the lymphatic system does not rely on the pumping action of the heart. Option D is incorrect as the correct answer is the combination of muscle contractions, breathing movements, and one-way valves, not all the options provided.

2. What is the main function of vacuoles in plant cells?

• A. To provide structural support for the cell
• B. To transport substances in and out of the cell
• C. To synthesize proteins and lipids
• D. To store water, enzymes, and waste products

Correct answer: D

Rationale: Vacuoles in plant cells primarily function as storage organelles. They store water, enzymes, pigments, and waste products, helping to maintain turgor pressure within the cell. This turgor pressure provides structural support for the plant cell. While vacuoles can also participate in transporting substances within the cell, their main role is storage. The synthesis of proteins and lipids is mainly handled by other organelles such as the endoplasmic reticulum and Golgi apparatus. Choice A is incorrect because while vacuoles indirectly contribute to structural support by maintaining turgor pressure, their primary function is storage. Choice B is incorrect as vacuoles are not primarily responsible for transporting substances in and out of the cell. Choice C is incorrect as vacuoles do not synthesize proteins and lipids; this function is carried out by other organelles.

3. Which part of the heart receives oxygenated blood from the lungs?

• A. Left atrium
• B. Right atrium
• C. Left ventricle
• D. Right ventricle

Correct answer: A

Rationale: The correct answer is A, the left atrium. The left atrium receives oxygenated blood from the lungs, which is then pumped into the left ventricle and out to the rest of the body. The right atrium receives deoxygenated blood from the body and sends it to the right ventricle to be pumped to the lungs for oxygenation. Choices B, C, and D are incorrect as they do not directly receive oxygenated blood from the lungs.

4. What happens during a physical change in matter?

• A. A new substance with different properties is formed
• B. The chemical composition of the substance changes
• C. The original substance can be recovered by physical means
• D. Energy is either released or absorbed

Correct answer: C

Rationale: During a physical change in matter, the original substance undergoes a change in its physical state or appearance without any change in its chemical composition. This means that the original substance can be recovered by physical means, such as melting, freezing, boiling, or condensing. No new substance is formed (option A), the chemical composition remains the same (option B), and energy changes can occur but are not a defining characteristic of a physical change (option D). The ability to recover the original substance by physical means distinguishes physical changes from chemical changes.

5. Which of the following is the main organ responsible for producing enzymes?

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

Correct answer: B

Rationale: The main organ responsible for producing enzymes is the pancreas. Enzymes are proteins that act as biological catalysts to speed up chemical reactions in the body. The pancreas produces and releases digestive enzymes that help break down carbohydrates, proteins, and fats in the small intestine to aid in the digestion and absorption of nutrients. While the liver also plays a role in producing bile, which helps in the digestion and absorption of fats, the primary organ responsible for producing enzymes is the pancreas. The stomach produces gastric juices containing hydrochloric acid and pepsin to help break down food, but it is not the primary organ for enzyme production. The small intestine is where most nutrient digestion and absorption occur; however, it receives enzymes from organs like the pancreas rather than producing them itself.

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