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 B
Explanation
A. While phagocytes move to areas of infection or damage, their primary role is not clumping together and adhering to tissues but rather engulfing and digesting foreign particles.
B. Phagocytes, such as neutrophils and macrophages, are white blood cells that ingest and digest foreign pathogens, dead cells, and debris in damaged tissues. This is their primary function in the immune response.
C. Releasing histamine is the function of mast cells, not phagocytes. Histamine is involved in initiating inflammation, but phagocytes are focused on clearing pathogens and debris.
D. Transporting oxygen is the function of red blood cells, not phagocytes. Phagocytes are involved in immune defense, not in the transport of oxygen.
Correct Answer is B
Explanation
A. Dehydration does not directly stimulate the production of erythrocytes. While dehydration can affect blood volume and viscosity, it is not a primary factor in erythropoiesis (the production of red blood cells).
B. Hypoxia (low oxygen levels) stimulates the production of erythropoietin, a hormone produced by the kidneys that promotes the formation of new erythrocytes in the bone marrow. This response helps improve oxygen delivery to tissues.
C. Inflammation triggers the immune response and can affect various blood cell types, but it does not directly stimulate erythropoiesis.
D. Infection can affect blood cell counts, but it is not a direct stimulus for the production of erythrocytes. The body may produce white blood cells as part of the immune response, but not red blood cells specifically.
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.