Nursing Elites

1. During normal breathing, which muscle is the primary driver of inhalation by contracting and flattening to increase the volume of the thoracic cavity?

• A. Diaphragm
• B. Intercostal muscles
• C. Abdominal muscles
• D. Pectoral muscles

Correct answer: A

Rationale: The diaphragm is the primary muscle responsible for inhalation during normal breathing. When it contracts, it flattens, increasing the volume of the thoracic cavity and creating a negative pressure that allows air to flow into the lungs. Intercostal muscles also play a role in expanding the chest cavity during inhalation, but the diaphragm is the main driver of the process. Abdominal muscles are primarily involved in exhalation by pushing the diaphragm upward to expel air from the lungs. Pectoral muscles are involved in movements of the arms and shoulders, not in breathing, making them incorrect choices for this question.

2. Which cells myelinate neurons in the PNS?

• A. Oligodendrocytes
• B. Astrocytes
• C. Schwann cells
• D. Microglia

Correct answer: C

Rationale: Schwann cells are the glial cells responsible for myelinating neurons in the peripheral nervous system (PNS). They form the myelin sheath around axons, which helps in the conduction of electrical impulses. Oligodendrocytes, on the other hand, myelinate neurons in the central nervous system (CNS). Astrocytes primarily provide support for neuronal function by regulating the chemical environment around neurons and maintaining the blood-brain barrier. Microglia are part of the immune response in the CNS, where they act as the resident macrophages, playing a role in immune surveillance and response to injury or disease. Therefore, the correct answer is Schwann cells (Choice C) as they specifically myelinate neurons in the PNS, differentiating them from the other cell types mentioned in the choices.

3. Which plane divides the body into anterior (front) and posterior (back) halves?

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

Correct answer: B

Rationale: The correct answer is B - Frontal/Coronal Plane. This plane divides the body into anterior (front) and posterior (back) halves. The sagittal plane divides the body into left and right halves, the transverse plane separates the body into superior (upper) and inferior (lower) portions. The horizontal plane is not a standard anatomical term for body division and does not provide division into front and back halves.

4. Where does the electron transport chain occur in the cell?

• A. Cytosol
• B. Golgi apparatus
• C. Inner mitochondrial membrane
• D. Nucleus

Correct answer: C

Rationale: The electron transport chain occurs in the inner mitochondrial membrane. This process is crucial for the generation of ATP, the cell's energy currency. Choice A (Cytosol) is incorrect as the electron transport chain does not take place in the cytosol. Choice B (Golgi apparatus) is also incorrect as the Golgi apparatus is involved in modifying, sorting, and packaging of proteins. Choice D (Nucleus) is incorrect as the nucleus houses the cell's genetic material but is not the location of the electron transport chain.

5. What is the name of the bone marrow cavity in the long bones where red blood cells are produced?

• A. Periosteum
• B. Diaphysis
• C. Medullary cavity
• D. Epiphysis

Correct answer: C

Rationale: The medullary cavity is the correct answer. It is the central cavity within the shafts of long bones where red bone marrow is located, responsible for the production of red blood cells. The periosteum is the outer layer of bone that provides nourishment and participates in bone repair. The diaphysis refers to the shaft of a long bone that contains yellow bone marrow. The epiphysis is the end of a long bone involved in joint articulation and contains red bone marrow in children for blood cell production.

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