Final answer:
Myelination is the process where myelin sheaths are wrapped around neurons' axons. It is essential for efficient neural communication, enhancing cognitive and motor functions, and is not fully completed until around age 20. While ongoing myelination during adolescence may affect teen behavior, it does not remove responsibility for actions.
Step-by-step explanation:
The process of myelination involves the wrapping of myelin sheaths around the axons of neurons. This is performed by glial cells, such as Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system. Myelination significantly increases the speed of electrical impulse conduction along neural pathways, which contributes to the development of complex brain functions - including those involved in driving skills for teen drivers.
During adolescence, an increase in white matter relative to grey matter in the cerebrum can be observed, indicating ongoing myelination. This white matter development is essential for efficient neural communication and underlies improvements in cognitive and motor function. However, it also highlights why teen drivers might face challenges such as decision-making and risk assessment, because their brains are still developing.
Neurological disorders like phenylketonuria (PKU) and multiple sclerosis (MS) highlight the critical role of myelin. PKU resulting in myelin reduction can lead to cognitive deficits, while MS involves myelin sheath loss, affecting motor control and other functions. This illustrates how myelin's presence enables normal neurological function.
On the topic of adolescent behavior and responsibility, while the process of myelination is not complete until around 20 years of age, this fact is only one of many factors contributing to behavior and does not absolve teens from responsibility for their actions. It does, however, suggest a need for understanding and contextual assessment of adolescent behavior.