Myelin is important in allowing electrical signals to be transferred from one axon to another adjacent axon insulating axons and increasing the conduction velocity of action potentials maintaining the ionic balance in the environment surrounding the axon absorbing damaged tissue or invading organisms

The correct answer for the fill in the blank is insulating axons and increasing the conduction velocity of action potentials.

Myelin sheath is an insulating sheath present around the axon of almost all nerve fibers. This insulating sheath contains breaks in between, which are called Nodes of Ranvier. It helps in increasing the conduction velocity of action potential because impulses jump from one Node of Ranvier to the next. Due to this, action potential travels very fast.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.