Answer: Myelin
Explanation:
The speed of the neurotransmission increases as we grow. The behavior of the teenager is quite different from the behavior of the adolescents.
They are more active, heroic and wants to take risk. This is because their brains are not completely developed till they reach the age of 25.
As they grow and reach the late 20s the white mater in the brain increases as the frontal lobe is the last part of the brain development.
Due to the development of the myelin in the frontal lobe the transmission of the signal increases at adolescence.
All of the mentioned types of cells here - blood, muscle and bone cells represent specialized cells which have a different role in your system and with that also differently affect the optimal funcitoning of our body. With any of these lacking, we would witness a loss of bodily function. .