Nursing Elites

1. What is the protective fluid that surrounds the brain and spinal cord?

• A. Blood
• B. Cerebrospinal fluid
• C. Myelin sheath
• D. Insulin

Correct answer: B

Rationale: Cerebrospinal fluid is the protective fluid that surrounds the brain and spinal cord. It acts as a cushion to protect these vital organs from injury and provides nutrients and removes waste products. Blood, myelin sheath, and insulin do not serve as the protective fluid surrounding the brain and spinal cord. Blood carries nutrients and oxygen to cells, myelin sheath is a protective covering of nerve fibers, and insulin is a hormone involved in regulating blood sugar levels.

2. Which of the following conditions is characterized by a high percentage of CO2 and a very low percentage of O2 in the blood?

• A. Asphyxia
• B. Emphysema
• C. Eupnea
• D. Hypoxia

Correct answer: A

Rationale: Asphyxia is the correct answer as it refers to a condition with high CO2 and low O2 levels in the blood. Asphyxia can result in oxygen deprivation and excess carbon dioxide in the bloodstream, posing a life-threatening situation if not treated promptly. Emphysema is a chronic lung disease characterized by the damage to the air sacs in the lungs, leading to breathing difficulties. Eupnea denotes normal breathing without any abnormalities. Hypoxia, on the other hand, involves low oxygen levels reaching the body's tissues, which can result from various causes such as reduced oxygen in the air or respiratory issues.

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. What term describes the functional unit of a skeletal muscle responsible for muscle contraction?

• A. Myofibril
• B. Sarcomere
• C. Tendon
• D. Myoglobin

Correct answer: B

Rationale: The correct answer is B, 'Sarcomere.' The sarcomere is indeed the functional unit of a skeletal muscle responsible for muscle contraction. It is composed of actin and myosin filaments that interact to generate muscle contraction. Choice A, 'Myofibril,' is incorrect as myofibrils are composed of sarcomeres, not the functional units themselves. Choice C, 'Tendon,' is incorrect as tendons connect muscles to bones and do not directly participate in muscle contraction. Choice D, 'Myoglobin,' is incorrect as myoglobin is a protein that stores oxygen in muscle cells and is not directly involved in muscle contraction.

5. Which of the following hormones regulates calcium levels in the blood?

• A. Insulin
• B. Parathyroid hormone
• C. Thyroid hormone
• D. Glucagon

Correct answer: B

Rationale: The correct answer is B, Parathyroid hormone. Parathyroid hormone plays a crucial role in regulating calcium levels in the blood by increasing calcium levels when they are too low. This hormone acts on the bones, kidneys, and intestines to ensure proper calcium balance in the body. Insulin (choice A) is involved in glucose metabolism, not calcium regulation. Thyroid hormone (choice C) primarily regulates metabolism, and while it indirectly influences calcium levels, it is not the primary regulator. Glucagon (choice D) is involved in increasing blood glucose levels, not calcium regulation.

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