Nursing Elites

1. From which type of tissue is the myelin sheath derived, a fatty substance that insulates nerve fibers?

• A. Epithelial tissue
• B. Muscle tissue
• C. Nervous tissue (glial cells)
• D. Connective tissue

Correct answer: C

Rationale: The myelin sheath, a fatty substance that insulates nerve fibers, is derived from nervous tissue, specifically glial cells. Glial cells, including oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system, are responsible for producing the myelin sheath that surrounds and insulates nerve fibers, aiding in the conduction of nerve impulses. Epithelial tissue (Choice A), Muscle tissue (Choice B), and Connective tissue (Choice D) are not responsible for producing the myelin sheath; instead, nervous tissue (glial cells) plays this crucial role.

2. Which hormone, produced by the thyroid gland, plays a key role in regulating calcium levels in the blood by promoting calcium release from bones and increasing calcium reabsorption in the kidneys?

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

Correct answer: A

Rationale: Calcitonin, produced by the thyroid gland, is responsible for regulating calcium levels in the blood. It works by decreasing blood calcium levels through two main mechanisms: promoting calcium uptake by bones and decreasing calcium reabsorption in the kidneys. Parathyroid hormone (PTH), on the other hand, increases blood calcium levels by promoting calcium release from bones and increasing calcium absorption in the intestines. Thyroxine, another thyroid hormone, primarily regulates metabolism and has no direct influence on calcium levels. Insulin, produced by the pancreas, is involved in regulating blood sugar levels and is not related to calcium homeostasis.

3. What is the monomer for nucleic acids?

• A. Nucleotide
• B. Amino acid
• C. Phosphate group
• D. Ribosome

Correct answer: A

Rationale: The correct answer is A: Nucleotide. Nucleotides are indeed the monomers that make up nucleic acids like DNA and RNA. They consist of a sugar molecule, a phosphate group, and a nitrogenous base. Amino acids are the monomers of proteins, not nucleic acids. While the phosphate group is a component of nucleotides, it is not the sole monomer. Ribosome is a cellular organelle involved in protein synthesis and is not a monomer for nucleic acids.

4. Which gland produces the hormone responsible for the 'fight-or-flight' response in stressful situations?

• A. Thyroid gland
• B. Pituitary gland
• C. Adrenal gland
• D. Pancreas

Correct answer: C

Rationale: The correct answer is C: Adrenal gland. The hormone responsible for the 'fight-or-flight' response in stressful situations is produced by the adrenal gland. This hormone is called adrenaline (epinephrine) and is released in response to stress, preparing the body to either fight the stressor or flee from it. The other choices are incorrect because the thyroid gland primarily produces hormones that regulate metabolism, the pituitary gland produces various hormones that control other endocrine glands, and the pancreas produces insulin and glucagon to regulate blood sugar levels.

5. Differentiate between the digestive and respiratory systems.

• A. Mouth
• B. Stomach
• C. Small intestine
• D. Lungs

Correct answer: D

Rationale: The correct answer is D - Lungs. The mouth, stomach, and small intestine are all components of the digestive system, which is responsible for breaking down food into nutrients that the body can absorb. On the other hand, the lungs are part of the respiratory system, which facilitates the exchange of oxygen and carbon dioxide between the body and the environment through breathing. While the digestive system processes food for energy and nutrients, the respiratory system is primarily focused on the exchange of gases necessary for cellular respiration. Choices A, B, and C are incorrect as they are all organs associated with the digestive system and do not pertain to the respiratory system.

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