Final answer:
A node of Ranvier is the gap between two consecutive myelin sheaths on an axon that is essential for swift nerve impulse conduction via saltatory conduction. It is formed by glial cells, such as Schwann cells and oligodendrocytes, which produce the insulating myelin sheath.
Step-by-step explanation:
The term for a space between two consecutive myelin sheaths where an axon is exposed is called a node of Ranvier. These gaps are critical in the rapid transmission of nerve impulses along the axon, as they allow the electrical signal to be 'recharged' as it propagates. Unlike the continuous insulation provided by the sheath, these nodes facilitate a form of impulse propagation known as saltatory conduction, where the impulse jumps from node to node, thereby increasing the speed at which the signal travels.
A Schwann cell, which is found on an axon in the peripheral nervous system, and the oligodendrocyte in the central nervous system, are types of glial cells responsible for the production of the myelin sheath. Myelination helps to insulate the axon and preserve the strength of the electrical signal over long distances. Disorders such as multiple sclerosis (MS) that affect the myelin sheath can lead to severe symptoms due to the interruption of this efficient signal transmission.