AP PSYCHOLOGY

Detailed explanation-1: -Similarly, myelin sheath around an axon is able to prevent electrical impulses from traveling through the sheath and out of the axon. It prevents the movement of ions into or out of the neuron, also known as depolarization. This means the current of action potential will only flow down the axon.

Detailed explanation-2: -Each section of myelin is called an internode. Each gap in the myelin sheath-between internodes-is called the nodes of Ranvier. The nodes of Ranvier are rich in positive sodium ions. As the electrical signal or impulse travels along the axon, it jumps from one node to the next.

Detailed explanation-3: -Myelin is an insulating layer, or sheath that forms around nerves, including those in the brain and spinal cord. It is made up of protein and fatty substances. This myelin sheath allows electrical impulses to transmit quickly and efficiently along the nerve cells. If myelin is damaged, these impulses slow down.

Detailed explanation-4: -Myelination allows for an increased rate of action potential transmission due to action potentials “jumping” between Node of Ranvier, this is called saltatory conduction.

Detailed explanation-5: -By acting as an electrical insulator, myelin greatly speeds up action potential conduction (Figure 3.14). For example, whereas unmyelinated axon conduction velocities range from about 0.5 to 10 m/s, myelinated axons can conduct at velocities up to 150 m/s.