Nursing Elites

1. The dome-shaped muscular structure that separates the chest cavity from the abdominal cavity is the:

• A. Diaphragm
• B. Sternum
• C. Pericardium
• D. Trachea

Correct answer: A

Rationale: The correct answer is A: Diaphragm. The diaphragm is a dome-shaped muscular structure that plays a crucial role in respiration by contracting and flattening during inhalation to increase the volume of the thoracic cavity, allowing the lungs to expand and fill with air. It separates the chest cavity (thoracic cavity) from the abdominal cavity. The sternum (B) is a flat bone in the center of the chest, the pericardium (C) is a double-layered sac that surrounds the heart, and the trachea (D) is the windpipe that connects the larynx to the bronchi. Therefore, the diaphragm is the correct answer in this case.

2. A decorative globe has a diameter of 25cm. What is its total surface area?

• A. 1570 sq cm
• B. 1963 sq cm
• C. 2513 sq cm
• D. 3142 sq cm

Correct answer: B

Rationale: Use the formula for surface area of a sphere: 4 * π * (radius)^2, where radius is half the diameter. Calculate the radius (12.5cm) and substitute: 4 * π * (12.5cm)^2 ≈ 1963 sq cm.

3. What is the myelin sheath and what does it do?

• A. A group of nerve cells that perform a specific function.
• B. A fatty substance that insulates some nerve fibers.
• C. A fluid-filled cavity within the brain.
• D. The junction between two neurons.

Correct answer: B

Rationale: The correct answer is B. The myelin sheath is a fatty substance that insulates some nerve fibers. It is essential for the proper functioning of the nervous system as it acts as an insulator, allowing for faster transmission of nerve impulses along the axon. Without the myelin sheath, nerve signals could be disrupted or weakened, leading to issues with movement, sensation, and other neurological functions. Options A, C, and D are incorrect as they do not accurately describe the myelin sheath or its function.

4. What property of a substance remains constant regardless of the amount of the substance present?

• A. Mass
• B. Weight
• C. Density
• D. Volume

Correct answer: c

Rationale: Density remains constant for a specific substance regardless of the quantity present. It's the mass per unit volume and remains the same for a substance.

5. The hormone responsible for milk production in the breasts after childbirth is:

• A. Estrogen
• B. Prolactin
• C. Oxytocin
• D. Relaxin

Correct answer: B

Rationale: The correct answer is B: Prolactin. Prolactin is the hormone responsible for milk production in the breasts after childbirth. It is produced by the pituitary gland and stimulates the alveoli in the breasts to produce milk. Estrogen plays a role in breast development during pregnancy but is not responsible for milk production. Oxytocin is responsible for the ejection of milk from the breasts during breastfeeding. Relaxin is a hormone that helps prepare the body for childbirth by relaxing the ligaments in the pelvis. Therefore, the hormone directly responsible for milk production after childbirth is prolactin.

6. How does the structure of centromeres contribute to chromosome movement during mitosis?

• A. The centromere provides a binding site for spindle fibers, allowing chromosomes to be attached and manipulated.
• B. The centromere serves as a dividing point between sister chromatids, ensuring their separation during anaphase.
• C. The centromere maintains chromosome stability by preventing chromosomal breaks and rearrangements.
• D. The centromere plays a role in DNA replication, ensuring accurate copying of the genetic material.

Correct answer: A

Rationale: Rationale: A) The centromere provides a binding site for spindle fibers, which are microtubules that help move chromosomes during cell division. This attachment allows the chromosomes to be pulled towards opposite poles of the cell during mitosis. Therefore, the structure of centromeres directly contributes to chromosome movement during mitosis by facilitating the attachment and manipulation of chromosomes by the spindle fibers. B) While the centromere does serve as a dividing point between sister chromatids, ensuring their separation during anaphase, this function is more related to the segregation of chromosomes rather than their movement. C) The centromere does play a role in maintaining chromosome stability by ensuring proper chromosome segregation, but it is not primarily responsible for preventing chromosomal breaks and rearrangements. D) The centromere is not directly involved in DNA replication. Its main function is

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