Why A Myelinated Neuron Conducts Impulses Faster?

In a myelinated nerve fiber, the conduction of impulse is faster due to the presence of Myelin sheath and node of Ranvier.  As the rate of impulse conduction in a nervous system depends on the diameter of a nerve fiber and the presence or absence of myelin sheath. 

Neurons with myelin sheath conduct impulse much faster than those without the presence of myelin. Schwann cells (or oligodendrocytes) are located at various regular intervals along the axons of the neuron. Between the areas of myelin are non-myelinated areas present, called as the nodes of Ranvier. Because fat or lipid molecules (myelin) acts as an insulator, a membrane coated with myelin does not conduct an impulse. So, in a myelinated neuron, action potentials occur only along with the nodes and, therefore, impulses jump over the areas of myelin, going from node to node in a process called as saltatory conduction.

Action potential velocity

Brain cells are also called neurons which send information and signals throughout the brain and body. The information is sent through electrochemical signals known as action potentials that travel along the length of the neuron. These neurons are then triggered to release various membrane receptors called neurotransmitters which help trigger the action potentials in corresponding cells, and so help the signal to spread all over.

Although, not all information is equally important or quick. Especially when it comes to the sensations such as touch, blink, and position sense, there are other signals in your body need to tell your brain about the exact time or now itself, and some that can wait a little while to be processed and should be lagged. For example, pain from a cut on your finger travels faster than pain originating in your kidney. This means that different types of information and impulse will be sent on different types of neurons.

Conduction velocity

Myelination of neurons improves the conduction velocity the speed with which the action potentials travel in axons present in the axial region of the neurons. Axon diameter also affects conduction speed: fatter axons that contain lipid proteins carry action potentials faster. So there are two important factors that determine how faster an action potential runs down an axon: diameter and myelination. Most importantly the signals from the adrenalin hormones which are activated quick and signals are sent just in the blink of an eye.