Nursing Elites

1. Which of the following is the main organ responsible for producing antibodies?

• A. Thymus gland
• B. Spleen
• C. Bone marrow
• D. Lymph nodes

Correct answer: C

Rationale: Antibodies are proteins produced by specialized white blood cells called B lymphocytes (B cells). These B cells mature in the bone marrow, where they undergo a process of differentiation and maturation to become plasma cells that secrete antibodies. The bone marrow is the primary site for the production of B cells and antibodies in the immune system. The thymus gland is responsible for the maturation of T lymphocytes (T cells), not antibody production. The spleen and lymph nodes play roles in filtering and trapping pathogens but are not the main organs responsible for producing antibodies.

2. What is the product of the complete combustion of propane (C3H8)?

• A. CO2
• B. CO
• C. CH4
• D. C

Correct answer: A

Rationale: The complete combustion of propane (C3H8) results in the production of carbon dioxide (CO2) and water. When a hydrocarbon such as propane undergoes complete combustion, the carbon atoms combine with oxygen to form CO2. This makes choice A, CO2, the correct answer. Choices B, C, and D are incorrect as CO is carbon monoxide, CH4 is methane, and C is elemental carbon, none of which are the primary product of the complete combustion of propane.

3. How many mL of a 0 M stock solution of HCl should be added to water to create 250 mL of a 50 M solution of HCl?

• A. 31.25 mL
• B. 32 mL
• C. 30 mL
• D. 31.3 mL

Correct answer: B

Rationale: To prepare 250 mL of a 50 M solution of HCl, the formula V1 x C1 = V2 x C2 is used, where V1 is the volume of the stock solution, C1 is the concentration of the stock solution, V2 is the final volume of the desired solution, and C2 is the final concentration of the desired solution. Given V1 x 0 M = 250 mL x 50 M, solving for V1 results in V1 = (250 mL x 50 M) / 0 M = 32 mL. Therefore, 32 mL of the 0 M stock solution of HCl needs to be added to water to create a 250 mL solution of 50 M HCl. Choices A, C, and D are incorrect because they do not represent the accurate volume required for the dilution calculation based on the given concentrations and volumes in the problem.

4. Which of the following is specialized tissue in the right atrium that acts as the heart’s natural pacemaker by generating the electrical signal for the heartbeat?

• A. sinus venosus
• B. sinoatrial node
• C. atrioventricular node
• D. tricuspid valve

Correct answer: B

Rationale: The sinoatrial node, often referred to as the SA node, is specialized tissue located in the right atrium of the heart. It functions as the heart's natural pacemaker by generating the electrical signal that initiates each heartbeat. This electrical signal spreads to the atrial muscles and then to the atrioventricular node, causing the heart to contract rhythmically and efficiently. The other options listed do not serve as the heart's natural pacemaker responsible for generating the electrical signal for the heartbeat. Sinus venosus is a developmental structure in fetal hearts, the atrioventricular node delays the electrical signal, and the tricuspid valve is a heart valve that prevents backflow of blood from the right ventricle to the right atrium.

5. What is the primary function of the spleen, an organ associated with the lymphatic system?

• A. Regulating blood sugar levels
• B. Filtering blood and destroying old red blood cells
• C. Producing digestive enzymes
• D. Secreting hormones

Correct answer: B

Rationale: The spleen is primarily responsible for filtering blood and destroying old or damaged red blood cells. It also aids in storing blood and producing specific types of white blood cells, contributing to maintaining blood quality and immune system function. Choices A, C, and D are incorrect because the spleen is not involved in regulating blood sugar levels, producing digestive enzymes, or secreting hormones. These functions are carried out by other organs in the body.

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