Which of the following components of a neuron is an insulative covering necessary for effective transmission of nerve impulses?
Myelin
Synapse
Axon
Dendrite
The Correct Answer is A
A. Myelin is a fatty substance that wraps around axons in many neurons. It acts as an insulative covering that speeds up the transmission of nerve impulses by enabling the signal to jump between gaps in the myelin (called nodes of Ranvier). This is the correct answer.
B. The synapse is the junction between two neurons where signals are transmitted. It is not involved in the insulative covering of a neuron.
C. The axon is the long, slender part of a neuron that transmits electrical signals, but it requires myelin to efficiently conduct those signals.
D. Dendrites are branched extensions of a neuron that receive signals from other neurons. They do not have an insulative function.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
A. The stomach plays a key role in digestion by breaking down food mechanically and chemically but does not play a significant role in nutrient absorption.
B. The large intestine is primarily involved in water and electrolyte absorption, as well as the formation of feces. It does not significantly contribute to nutrient absorption.
C. While some digestion begins in the mouth, particularly with enzymes in saliva, nutrient absorption does not occur there.
D. The small intestine is the primary site of nutrient absorption in the digestive system. Its walls are lined with villi and microvilli that increase surface area for the absorption of nutrients such as carbohydrates, proteins, fats, vitamins, and minerals.
Correct Answer is B
Explanation
A. Excessive aldosterone causes increased reabsorption of sodium and water, and the excretion of potassium. Therefore, excessive aldosterone would typically decrease plasma potassium levels, not increase them.
B. Aldosterone stimulates the kidneys to reabsorb sodium and excrete potassium, leading to increased plasma sodium levels. This is the correct effect of excessive aldosterone secretion.
C. Phosphorus levels are not directly affected by aldosterone; its primary role is in regulating sodium and potassium balance.
D. Aldosterone does not directly regulate calcium levels in the blood, so plasma calcium levels are not significantly affected by aldosterone secretion.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today
Report Wrong Answer on the Current Question
Do you disagree with the answer? If yes, what is your expected answer? Explain.
Kindly be descriptive with the issue you are facing.