Nursing Elites

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

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

Correct answer: B

Rationale: Sebaceous glands are responsible for secreting an oily substance called sebum, not sweat, cerumen, or mucus. Sebum plays a vital role in lubricating and waterproofing the skin and hair, preventing them from drying out. Sweat glands produce sweat to regulate body temperature. Cerumen is the medical term for earwax, produced by ceruminous glands in the ear canal, while mucus is a slimy substance that protects and lubricates body tissues. Therefore, the correct answer is B: Sebum, as it is the oily substance secreted by sebaceous glands.

2. What is the action of the triceps reflex?

• A. Forces contraction of the triceps and extension of the arm.
• B. Forces contraction of the biceps, relaxation of the biceps, and arm extension.
• C. Causes the triceps to contract, causing the forearm to supinate and flex.
• D. Causes the triceps to relax and the upper arm to pronate and extend.

Correct answer: A

Rationale: The triceps reflex causes the triceps muscle to contract, leading to the extension of the arm. This reflex is a protective response to sudden stretching of the triceps muscle, as seen when a physician taps the triceps tendon during a physical examination. Choice A is the correct answer as it accurately reflects the action of the triceps reflex. Choices B, C, and D are incorrect because they describe actions that are not associated with the triceps reflex. Biceps contraction, forearm supination, flexion, triceps relaxation, and pronation are not part of the triceps reflex arc.

3. Which statement accurately describes cytokinesis in animal cells?

• A. Which statement accurately describes cytokinesis in animal cells?
• B. A cell plate forms in the center of the dividing cell, eventually separating the cytoplasm into two daughter cells.
• C. A cell plate forms in the center of the dividing cell, eventually separating the cytoplasm into two daughter cells.
• D. The nucleus elongates and pulls apart, physically dividing the cytoplasm into two.

Correct answer: B

Rationale: A) This statement is a duplicate of option C and does not accurately describe cytokinesis in animal cells. B) In animal cells, during cytokinesis, a cleavage furrow forms in the center of the dividing cell. This furrow deepens and eventually pinches the cytoplasm into two daughter cells. This process is distinct from plant cells, where a cell plate forms. C) This statement is a duplicate of option A and does not accurately describe cytokinesis in animal cells. D) This statement describes the process of nuclear division (mitosis) rather than cytokinesis, which is the division of the cytoplasm.

4. How can a single gene mutation lead to multiple phenotypes depending on the organism?

• A. Pleiotropy describes the effect of one gene influencing multiple seemingly unrelated traits.
• B. Epigenetics involves environmental factors modifying gene expression without altering the DNA sequence.
• C. Genetic drift refers to random changes in allele frequencies within a population.
• D. Gene regulation controls the timing and level of gene expression within an organism.

Correct answer: A

Rationale: A single gene mutation can lead to multiple phenotypes through pleiotropy, where one gene influences diverse traits or functions in an organism. This phenomenon occurs when the mutated gene affects different biochemical pathways, developmental processes, or cellular functions, resulting in a cascade of downstream effects that manifest as a variety of phenotypic outcomes. Choice B, epigenetics, involves modifications in gene expression influenced by environmental factors without altering the DNA sequence, which is not directly related to the question about single gene mutations causing multiple phenotypes. Choice C, genetic drift, refers to random changes in allele frequencies within a population, which is unrelated to the impact of a single gene mutation on multiple phenotypes. Choice D, gene regulation, focuses on controlling the timing and level of gene expression within an organism, which is not directly addressing how a single gene mutation can lead to diverse phenotypes.

5. Which plane divides the body into left and right halves?

• A. Sagittal/Median Plane
• B. Frontal/Coronal Plane
• C. Transverse/Cross-Section Plane
• D. Horizontal Plane

Correct answer: A

Rationale: The correct answer is A: Sagittal/Median Plane. This plane divides the body into left and right halves. The Frontal/Coronal Plane (choice B) divides the body into front and back, while the Transverse/Cross-Section Plane (choice C) divides it into top and bottom. The Horizontal Plane (choice D) divides the body into upper and lower portions. Understanding these planes is essential in anatomy as they help describe the orientation and relationships of body structures.

Similar Questions