Nursing Elites

1. Why are isotopes of the same element chemically similar?

• A. They have the same number of protons.
• B. They have the same number of electrons.
• C. Their chemical properties are identical.
• D. They share the same electron configuration.

Correct answer: A

Rationale: Isotopes of the same element are chemically similar because they have the same number of protons. The number of protons in an atom determines its atomic number, which is the defining characteristic of an element. Since chemical reactions primarily involve interactions between the electrons of atoms, having the same number of protons means the atoms have the same basic chemical properties. While isotopes may differ in the number of neutrons, it is the number of protons that dictates the element's identity and chemical behavior. Therefore, choice A is correct because the number of protons directly influences an element's chemical properties, making isotopes of the same element chemically similar despite potentially having different numbers of neutrons. Choices B, C, and D are incorrect because isotopes of the same element can have different numbers of electrons, their chemical properties are not identical due to potential differences in neutron numbers, and although they may have similarities in electron configurations, it is the number of protons that is the key factor determining chemical behavior.

2. Which muscle has involuntary cells that are branched and striated and connected by intercalated discs with gap junctions?

• A. Smooth muscle
• B. Cardiac muscle
• C. Skeletal muscle
• D. Epithelial muscle

Correct answer: B

Rationale: The correct answer is B: Cardiac muscle. Cardiac muscle cells fit the description provided in the question; they are involuntary, striated, and branched, with intercalated discs containing gap junctions that allow for synchronized contractions of the heart. Smooth muscle (choice A) lacks striations and is found in the walls of internal organs. Skeletal muscle (choice C) is voluntary and attaches to bones for movement. 'Epithelial muscle' (choice D) is not a valid muscle type, making it an incorrect choice.

3. What is the function of the endocrine system?

• A. To protect the body from infection
• B. To release digestive enzymes
• C. To break down food
• D. To regulate the sleep-wake cycle

Correct answer: B

Rationale: The correct answer is B. The endocrine system releases hormones that regulate various functions, including metabolism and growth. It is responsible for producing and releasing hormones that control processes such as metabolism, growth, and development. The digestive enzymes are released by the digestive system, not the endocrine system. Choices A, C, and D are incorrect because protecting the body from infection is primarily the role of the immune system, breaking down food is the function of the digestive system, and regulating the sleep-wake cycle is controlled by the circadian rhythm which is mainly influenced by the brain's hypothalamus and not the endocrine system.

4. Which term refers to the relaxation of the heart muscle?

• A. Diastole
• B. Systole
• C. Asystole
• D. Cardiastole

Correct answer: A

Rationale: The correct answer is A: Diastole. Diastole is the phase of the heartbeat when the heart muscle relaxes, allowing the chambers to fill with blood. Systole, on the other hand, refers to the contraction phase of the heart when it pumps blood out. Asystole is the absence of heart contractions, often referred to as cardiac arrest. Cardiastole is not a recognized medical term in relation to heart muscle relaxation, making it an incorrect choice.

5. Which hormone, produced by the thyroid gland, regulates calcium levels in the blood by enhancing calcium absorption in the intestines and reducing calcium loss in the kidneys?

• A. Calcitonin
• B. Parathyroid hormone (PTH)
• C. Thyroxine
• D. Insulin

Correct answer: A

Rationale: Calcitonin is the hormone produced by the thyroid gland that regulates calcium levels in the blood. It enhances calcium absorption in the intestines and reduces calcium loss in the kidneys. Parathyroid hormone (PTH) operates oppositely to calcitonin by increasing calcium levels in the blood. Thyroxine is a thyroid gland hormone that primarily regulates metabolism, not calcium levels. Insulin, produced by the pancreas, is responsible for controlling blood sugar levels, not calcium levels. Therefore, the correct answer is Calcitonin as it specifically targets calcium regulation in the body.

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