Nursing Elites

1. Homologous structures are those that:

• A. Have the same function but different origins
• B. Have different functions but the same origin
• C. Are similar in appearance and function due to shared ancestry
• D. Are identical in both appearance and function

Correct answer: C

Rationale: Rationale: - Option A is incorrect because structures with the same function but different origins are analogous structures, not homologous structures. - Option B is incorrect because structures with different functions but the same origin are also not homologous structures; they are considered to be vestigial structures. - Option D is incorrect because structures that are identical in both appearance and function are not necessarily homologous; they could be the result of convergent evolution. Homologous structures are those that share similarities in appearance and function due to being inherited from a common ancestor. These structures may have undergone modifications over time to adapt to different functions in different species, but their fundamental similarities can be traced back to a shared evolutionary history.

2. What is the common name for the compound CH₃COOH?

• A. Acetic acid
• B. Formic acid
• C. Butyric acid
• D. Propionic acid

Correct answer: A

Rationale: CH₃COOH is commonly known as acetic acid. The other choices represent different organic acids.

3. What is the molar mass of Ca(NO3)2?

• A. 74.1 g/mol
• B. 132.1 g/mol
• C. 164.1 g/mol
• D. 78.1 g/mol

Correct answer: b

Rationale: Calculate the molar mass: Ca(40.08) + 2N(14.01) + 6O(16.00) = 132.1 g/mol.

4. Cartilage is a flexible connective tissue found in the:

• A. Center of long bones
• B. Joints between bones
• C. Muscle tissue
• D. Walls of blood vessels

Correct answer: A

Rationale: Cartilage is a flexible connective tissue that is found in the joints between bones. It is a strong yet flexible tissue that cushions and supports the joints, allowing for smooth movement and reducing friction between bones. Cartilage is not typically found in the center of long bones, muscle tissue, or walls of blood vessels. Therefore, the correct answer is B: 'Joints between bones.'

5. The stratum corneum, the outermost layer of the epidermis, is primarily composed of:

• A. Keratinized dead cells
• B. Melanocytes
• C. Langerhans cells
• D. Merkel cells

Correct answer: A

Rationale: The correct answer is A: 'Keratinized dead cells.' The stratum corneum is the outermost layer of the epidermis and is mainly composed of keratinized dead cells. These cells are flattened, fully keratinized, and provide a protective barrier for the skin against environmental factors such as pathogens, UV radiation, and water loss. Melanocytes (Option B), Langerhans cells (Option C), and Merkel cells (Option D) are all important components of the epidermis but are not the primary constituents of the stratum corneum. Melanocytes produce melanin, Langerhans cells are involved in the immune response, and Merkel cells are associated with the sense of touch.

6. Sebaceous glands, located in the dermis, secrete an oily substance called:

• A. Sweat
• B. Sebum
• C. Cerumen
• D. Mucus

Correct answer: B

Rationale: The correct answer is B: Sebum. Sebaceous glands are located in the dermis layer of the skin and are responsible for producing sebum, an oily substance that helps lubricate and waterproof the skin and hair. Sweat glands, on the other hand, are located in the dermis and subcutaneous layers and produce sweat to help regulate body temperature. Cerumen is produced by ceruminous glands in the ear canal to protect the ear, while mucus is produced by mucous glands in the respiratory system to help trap and remove particles. Therefore, sebum is the oily substance secreted by sebaceous glands in the dermis.

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