Question

question 3

which of the following is true regarding myelin?

• development of myelin is most dramatic during the first few years of life.
• myelin helps to slow the rate of impulses between cells.
• myelin starts to develop in adolescence.
• myelin is wrapped around the dendrites.

Explanation:

Analyze myelin function and structure

Using the Neuron Anatomy and Dendrites knowledge points, we evaluate the structural characteristics of myelin. Myelin is a fatty sheath wrapped around the axons of neurons, not the dendrites. Its primary physiological function is to insulate the axon, which significantly speeds up (rather than slows down) the transmission of electrical impulses along the cell.

Examine developmental timeline of myelination

Using the Brain Development knowledge point, we analyze the timeline of myelination. Myelination begins prenatally but is not delayed until adolescence; rather, the most rapid and dramatic development of myelin occurs during infancy and the first few years of life, continuing at a steadier pace into early adulthood.

Evaluate the given options

• Option 1: "Development of myelin is most dramatic during the first few years of life." This is correct because the rate of myelination peaks during infancy and early childhood.
• Option 2: "Myelin helps to slow the rate of impulses between cells." This is incorrect; myelin increases action potential conduction speed.
• Option 3: "Myelin starts to develop in adolescence." This is incorrect; it begins in utero.
• Option 4: "Myelin is wrapped around the dendrites." This is incorrect; it wraps around axons.

Answer:

• (A) Development of myelin is most dramatic during the first few years of life. (Correct answer)
• (B) Myelin helps to slow the rate of impulses between cells.
• (C) Myelin starts to develop in adolescence.
• (D) Myelin is wrapped around the dendrites.