Nursing Elites

1. Which of the following is a balanced chemical equation?

• A. H2 + O2 → H2O
• B. 2H2 + O2 → 2H2O
• C. 3H2O → 2H2 + O2
• D. H2O → H2 + O2

Correct answer: B

Rationale: A balanced chemical equation must have the same number of atoms of each element on both sides of the equation. In option B, 2H2 + O2 → 2H2O, the equation is balanced as there are 2 hydrogen atoms and 2 oxygen atoms on both the reactant and product sides after balancing, satisfying the law of conservation of mass. Option A is unbalanced as there are 2 oxygen atoms on the reactant side but only 1 oxygen atom on the product side. Option C is unbalanced with 3 hydrogen atoms on the reactant side and 2 hydrogen atoms on the product side. Option D is unbalanced with 1 oxygen atom on the reactant side and 2 oxygen atoms on the product side.

2. Epithelial tissue, which covers surfaces, is further classified based on the number of cell layers. Simple epithelium has:

• A. No layers
• B. One layer
• C. Two to several layers
• D. Many tightly packed layers

Correct answer: B

Rationale: Simple epithelium consists of a single layer of cells. This type of epithelium is found in areas where absorption, secretion, and filtration occur, as it allows for efficient exchange of substances across the epithelial barrier. Simple epithelium is well-suited for diffusion and filtration processes due to its thin nature, enabling substances to pass through easily. Choice A, 'No layers,' is incorrect as epithelial tissue always consists of at least one cell layer. Choice C, 'Two to several layers,' describes stratified epithelium, not simple epithelium, which has only one layer. Choice D, 'Many tightly packed layers,' is more characteristic of stratified epithelium, where multiple layers of cells are present. Therefore, the correct answer is B: 'One layer.'

3. What is the function of valves in arteries?

• A. To maintain high blood pressure for the proper diffusion of nutrients in capillaries.
• B. To prevent backflow of blood due to high pressure away from the heart.
• C. As a vestigial trait from evolution, like the appendix, that serves no purpose.
• D. Valves are absent in arteries but present in veins.

Correct answer: B

Rationale: Valves in arteries serve the crucial function of preventing backflow of blood. Arteries carry blood at high pressure away from the heart, and the valves ensure that blood flows in one direction, towards the capillaries, to maintain efficient circulation. Without these valves, there would be a risk of blood flowing backward, compromising the effectiveness of blood circulation in the body. Choices A, C, and D are incorrect. Choice A incorrectly suggests that valves maintain high blood pressure for nutrient diffusion in capillaries, which is not their function. Choice C inaccurately compares valves to vestigial traits, like the appendix, implying they serve no purpose, which is untrue. Choice D is incorrect as valves are indeed present in arteries to regulate blood flow, not just in veins.

4. During ejaculation, sperm travels through a tube from the testes to the urethra. What is the name of this tube?

• A. Vas deferens
• B. Epididymis
• C. Seminal vesicle
• D. Urethra

Correct answer: A

Rationale: The vas deferens is the correct answer. It is the tube that carries sperm from the testes to the urethra during ejaculation. The vas deferens plays a crucial role in transporting mature sperm for ejaculation. The epididymis is responsible for sperm maturation and storage, not the direct passage of sperm to the urethra. The seminal vesicle produces fluid that combines with sperm to form semen but is not the tube for sperm transport. The urethra serves as the passageway for both urine and semen out of the body but is not the specific tube that transports sperm from the testes to the urethra.

5. What hormones are produced in the ovaries, and what are their functions?

• A. Insulin: regulates blood sugar levels
• B. Progesterone: stimulates uterine lining growth
• C. Adrenaline: increases heart rate
• D. Cortisol: regulates stress response

Correct answer: B

Rationale: The correct answer is B. Progesterone, produced in the ovaries, stimulates uterine lining growth and plays a crucial role in regulating the menstrual cycle. Insulin is produced in the pancreas to regulate blood sugar levels, not in the ovaries. Adrenaline is produced by the adrenal glands and increases heart rate in response to stress or danger, not in the ovaries. Cortisol, also produced by the adrenal glands, helps regulate the body's response to stress, not in the ovaries.

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