Nursing Elites

1. Which structure in the heart 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 mitral valve, also known as the bicuspid valve, is located between the left atrium and the left ventricle of the heart. Its primary function is to prevent the backflow of blood from the left ventricle into the left atrium during ventricular contraction. The aortic valve (A) prevents the backflow of blood from the aorta into the left ventricle, the pulmonary valve (B) prevents the backflow of blood from the pulmonary artery into the right ventricle, and the tricuspid valve (C) prevents the backflow of blood from the right ventricle into the right atrium. Understanding the functions of these heart valves is crucial in maintaining proper blood flow through the heart and preventing regurgitation of blood into the wrong chambers.

2. According to Newton's third law of motion, for every action, there is an equal and opposite _________.

• A. Reaction
• B. Force
• C. Acceleration
• D. Momentum

Correct answer: A

Rationale: Newton's third law of motion states that for every action, there is an equal and opposite reaction. This law emphasizes that forces always exist in pairs. When one object exerts a force on a second object (action), the second object exerts an equal force in the opposite direction back on the first object (reaction). This principle is crucial in understanding the interactions between objects and the resulting motion observed in the physical world. Choices B, C, and D are incorrect because while force is involved, the specific concept highlighted by Newton's third law is the equal and opposite reaction. Acceleration and momentum are also related to motion but are not directly tied to Newton's third law of motion, which focuses on the equality and oppositeness of forces in interactions.

3. Which mineral is crucial for bone strength and is stored in bones and teeth?

• A. Calcium
• B. Iron
• C. Magnesium
• D. Potassium

Correct answer: A

Rationale: Calcium is crucial for bone strength as it is a major mineral stored in bones and teeth. It plays a vital role in maintaining bone density and strength, making it essential for overall bone health. Calcium is essential for various physiological functions, including muscle contraction, nerve transmission, and blood clotting. Inadequate calcium intake can lead to conditions like osteoporosis, where bones become weak and brittle. Iron (Choice B) is important for transporting oxygen in the blood, but it is not stored in bones and does not play a significant role in bone strength. Magnesium (Choice C) is essential for bone health, but it is not primarily stored in bones and teeth. Potassium (Choice D) is crucial for various physiological functions, such as fluid balance and muscle function, but it is not a major mineral stored in bones and teeth for bone strength.

4. How many grams of solid CaCO3 are needed to make 600 mL of a 35 M solution? The atomic masses for the elements are as follows: Ca = 40.1 g/mol; C = 12.01 g/mol; O = 16.00 g/mol.

• A. 18.3 g
• B. 19.7 g
• C. 21.0 g
• D. 24.2 g

Correct answer: B

Rationale: 1. First, calculate the molar mass of CaCO3 by adding the atomic masses of Ca, C, and 3 O atoms: 40.1 + 12.01 + (3 * 16.00) = 100.13 g/mol. 2. Calculate the number of moles in 600 mL of a 35 M solution: 600 mL * 35 mol/L = 21,000 mmol. 3. Convert moles to grams using the molar mass of CaCO3: 21,000 mmol * (100.13 g/mol / 1000 mmol/mol) = 2,102.73 g. 4. Therefore, you would need 19.7 g of solid CaCO3 to make 600 mL of a 35 M solution.

5. Which type of blood cell is primarily responsible for fighting infections?

• A. Red blood cell
• B. White blood cell
• C. Platelet
• D. Plasma

Correct answer: B

Rationale: The correct answer is B: White blood cell. White blood cells are the primary cells responsible for fighting infections and foreign invaders in the body. Red blood cells carry oxygen to tissues, platelets help in blood clotting to prevent excessive bleeding, and plasma is the liquid component of blood that carries cells and nutrients. White blood cells, also known as leukocytes, play a crucial role in the immune system by identifying and destroying pathogens, such as bacteria, viruses, and other harmful substances. Therefore, they are the key players in the body's defense against infections, making them the correct answer in this scenario. While red blood cells, platelets, and plasma have essential functions in the body, they are not primarily responsible for combating infections like white blood cells.

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