Nursing Elites

1. 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 myelin sheath is a fatty substance that insulates some nerve fibers. It is made up of specialized cells that wrap around the axons of neurons, providing insulation and speeding up the transmission of nerve impulses. Choice A is incorrect as the myelin sheath is not a group of nerve cells but rather a substance that surrounds nerve fibers. Choice C is incorrect as the myelin sheath is not a fluid-filled cavity within the brain. Choice D is incorrect as the myelin sheath is not the junction between two neurons.

2. What is the main function of the kidneys?

• A. To filter waste products from the blood
• B. To produce urine
• C. To regulate blood pressure
• D. To produce hormones that help control blood sugar levels

Correct answer: A

Rationale: The main function of the kidneys is to filter waste products, excess ions, and water from the bloodstream to form urine, which is then excreted from the body. This process helps maintain the body's internal environment by regulating the balance of electrolytes, fluid volume, and pH levels. While the kidneys do produce urine as a result of filtering the blood, their primary function is to filter waste products rather than solely producing urine. Although the kidneys play a role in regulating blood pressure by controlling blood volume and electrolyte concentration, their main function is waste filtration. While the kidneys do produce hormones like erythropoietin and renin that regulate physiological processes, such as red blood cell production and blood pressure, the main role of the kidneys is waste filtration.

3. What is involved in the involuntary reflex arc that withdraws your hand from a hot object?

• A. Central nervous system only
• B. Peripheral nervous system only
• C. Both CNS and PNS
• D. Sensory neurons only

Correct answer: C

Rationale: The involuntary reflex arc that withdraws your hand from a hot object involves both the central nervous system (CNS) and the peripheral nervous system (PNS). When your hand touches a hot object, sensory neurons in the PNS detect the heat and send signals to the spinal cord in the CNS. The spinal cord processes this information and sends a signal back through motor neurons in the PNS to move your hand away from the hot object. This coordinated response requires the collaboration of both the CNS and PNS to protect the body from harm. Choice A is incorrect because the reflex arc involves more than just the central nervous system. Choice B is incorrect because the reflex arc involves more than just the peripheral nervous system. Choice D is incorrect because the reflex arc also involves motor neurons, not just sensory neurons.

4. The lymphatic system works closely with which other body system to fight infections?

• A. Respiratory system
• B. Digestive system
• C. Immune system
• D. Nervous system

Correct answer: C

Rationale: The lymphatic system and the immune system work closely together to fight infections. The lymphatic system aids the immune system by circulating white blood cells, a crucial component in combating pathogens, throughout the body. This collaboration helps identify and eliminate harmful invaders to maintain the body's health and well-being. Choice A (Respiratory system) is incorrect because while it plays a role in oxygen exchange and removing carbon dioxide, it is not primarily responsible for fighting infections. Choice B (Digestive system) is incorrect as its main functions involve breaking down food and absorbing nutrients, not directly fighting infections. Choice D (Nervous system) is incorrect because its primary role is in transmitting signals throughout the body and controlling bodily functions, not in fighting infections.

5. What is the protective fluid surrounding the brain and spinal cord called?

• A. Blood
• B. Cerebrospinal fluid
• C. Plasma
• D. Myelin

Correct answer: B

Rationale: Cerebrospinal fluid is the protective fluid that surrounds the brain and spinal cord. It acts as a cushion to protect these vital organs from injury and provides nutrients to the nervous system. Blood, plasma, and myelin are not the fluids specifically surrounding the brain and spinal cord. Blood is found within blood vessels, plasma is the liquid component of blood, and myelin is a fatty substance that forms a protective sheath around nerve fibers.

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