Nursing Elites

1. Which of the following cations is found at the center of a heme?

• A. Cr (III)
• B. Cu (II)
• C. Iron (II)
• D. Iron (III)

Correct answer: C

Rationale: The correct answer is Iron (II) (Fe2+), which is the cation found at the center of a heme group. Heme contains an iron (II) ion that is coordinated within the porphyrin ring structure. This iron ion is crucial for the function of heme in binding and transporting oxygen in hemoglobin and myoglobin. Choice A (Cr (III)) is incorrect as chromium is not typically found at the center of a heme group. Choice B (Cu (II)) is incorrect as copper is not the cation typically present in heme. Choice D (Iron (III)) is also incorrect as heme predominantly contains iron (II) at its center, not iron (III).

2. What is the main function of the urinary system?

• A. Transporting oxygen
• B. Fighting off infections
• C. Maintaining acid-base balance
• D. All of the above

Correct answer: C

Rationale: The main function of the urinary system is to maintain the body's acid-base balance. This is achieved by regulating the levels of electrolytes and water in the body. The kidneys filter waste products from the blood to form urine, which helps to regulate the pH balance. Choice A, transporting oxygen, is primarily the function of the respiratory system. Choice B, fighting off infections, is a function of the immune system. Therefore, the correct answer is maintaining acid-base balance.

3. Which of the following describes a reflex arc?

• A. The storage and recall of memory
• B. The maintenance of visual and auditory acuity
• C. The autoregulation of heart rate and blood pressure
• D. A stimulus and response controlled by the spinal cord

Correct answer: D

Rationale: Choice D correctly describes a reflex arc. A reflex arc is a neural pathway that controls a reflex action. It involves a specific sequence of events that occur in response to a stimulus, which is rapidly and involuntarily processed by the spinal cord. The spinal cord coordinates the quick processing of sensory input and the generation of a motor response without involving the brain, allowing for rapid protective responses. Choices A, B, and C are incorrect because they do not accurately describe a reflex arc. A reflex arc is specifically related to the rapid and involuntary response to a stimulus through neural pathways involving the spinal cord, not memory storage, visual and auditory acuity maintenance, or heart rate and blood pressure autoregulation.

4. What are the moon-shaped white structures at the base of fingernails called?

• A. Lunulae
• B. Cuticle
• C. Hyponychium
• D. Matrix

Correct answer: A

Rationale: The correct answer is A: Lunulae. The moon-shaped white structures at the base of fingernails are known as lunulae. They are most prominent on the thumb and are situated at the base of the nail matrix. The lunula is the visible part of the nail matrix, which is responsible for generating new nail cells. Choice B, Cuticle, is incorrect as it refers to the thin layer of skin at the base of the nail plate. Choice C, Hyponychium, is incorrect as it is the skin that lies beneath the free edge of the nail. Choice D, Matrix, is incorrect as it is the area where the nail is formed, located under the cuticle.

5. Which organ produces insulin, a hormone responsible for regulating blood sugar levels?

• A. Parathyroid gland
• B. Pancreas
• C. Thymus gland
• D. Ovaries

Correct answer: B

Rationale: Insulin is a hormone produced by the pancreas. Beta cells located in the islets of Langerhans within the pancreas are responsible for insulin production. Insulin plays a crucial role in regulating blood sugar levels by promoting the uptake of glucose into cells, thereby maintaining blood sugar levels within a normal range. Choices A, C, and D are incorrect because the parathyroid gland is primarily involved in regulating calcium levels, the thymus gland is involved in immune function, and the ovaries are involved in reproductive functions, not insulin production for blood sugar regulation.

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