Nursing Elites

1. What causes varicose veins to occur?

• A. Atherosclerosis.
• B. Incompetent valves.
• C. Loss of skin turgor.
• D. Loss of blood vessel elasticity.

Correct answer: B

Rationale: Varicose veins occur when the valves within the veins become incompetent, leading to blood pooling in the veins instead of being efficiently pumped back to the heart. This causes the veins to become enlarged, twisted, and visible under the skin. Factors such as genetics, aging, pregnancy, and prolonged standing or sitting can contribute to the development of incompetent valves and the resulting varicose veins. Atherosclerosis is the buildup of plaque in arteries, not veins, and does not directly cause varicose veins. Loss of skin turgor is related to skin elasticity and not a direct cause of varicose veins. Loss of blood vessel elasticity is a general term and does not specifically address the mechanism behind varicose veins, which is primarily due to incompetent valves.

2. In the reaction 2Na + 2H2O → 2NaOH + H2, what is the limiting reactant when 3 moles of sodium react with 2 moles of water?

• A. Na
• B. H2O
• C. NaOH
• D. H2

Correct answer: A

Rationale: The balanced chemical equation indicates that 2 moles of sodium react with 2 moles of water to yield 2 moles of sodium hydroxide and 1 mole of hydrogen gas. When 3 moles of sodium react with only 2 moles of water, sodium becomes the limiting reactant as it is present in excess compared to the available water molecules. This situation arises because not all sodium atoms can fully react with the limited amount of water, resulting in sodium being the limiting reactant in this specific case. Choice B (H2O), choice C (NaOH), and choice D (H2) are incorrect as they are not the limiting reactant in the given reaction scenario.

3. What makes bone resistant to shattering?

• A. The calcium salts deposited in the bone
• B. The collagen fibers
• C. The bone marrow and network of blood vessels
• D. The intricate balance of minerals and collagen fibers

Correct answer: D

Rationale: Bone is resistant to shattering due to the intricate balance of minerals and collagen fibers. The minerals provide strength to the bone, while the collagen fibers offer flexibility. This combination ensures that bone is a robust and resilient tissue. Choice A (The calcium salts deposited in the bone) is incorrect as calcium salts alone do not provide the necessary flexibility for bone to withstand shattering. Choice B (The collagen fibers) is partially correct as collagen fibers contribute to the flexibility of bone but alone are not sufficient for resistance to shattering. Choice C (The bone marrow and network of blood vessels) is incorrect as they do not directly contribute to the physical resistance of bone to shattering.

4. What type of vessel carries oxygen-rich blood from the heart to other tissues of the body?

• A. Veins
• B. Intestines
• C. Bronchioles
• D. Arteries

Correct answer: D

Rationale: The correct answer is D: Arteries. Arteries are blood vessels that carry oxygen-rich blood away from the heart to supply oxygen to the tissues and organs throughout the body. Veins, choice A, carry oxygen-poor blood back to the heart, not oxygen-rich blood. Intestines, choice B, are part of the digestive system and do not play a role in carrying blood. Bronchioles, choice C, are small air passages in the lungs responsible for carrying air, not blood.

5. What is the primary function of coronary arteries?

• A. Delivering oxygenated blood throughout the body.
• B. Supplying oxygenated blood to the heart muscle itself.
• C. Carrying deoxygenated blood back to the heart.
• D. Regulating blood pressure through vasoconstriction and vasodilation.

Correct answer: B

Rationale: The primary function of coronary arteries is to supply oxygenated blood to the heart muscle itself. The heart is a muscle that needs a constant supply of oxygen and nutrients to function properly. Coronary arteries branch off the aorta and specifically deliver oxygenated blood to the heart muscle, ensuring its proper function. Choice A is incorrect because coronary arteries do not deliver blood throughout the entire body but specifically to the heart. Choice C is incorrect as coronary arteries carry oxygenated blood away from the heart. Choice D is incorrect as the primary function of the coronary arteries is not to regulate blood pressure but rather to provide oxygenated blood to the heart muscle.

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