Final answer:
The Node of Ranvier refers to the gap between the myelin sheath segments along an axon, essential for rapid electrical signal transmission through a process known as saltatory conduction.
Step-by-step explanation:
In the vertebrate nervous system, the term "Node of Ranvier" refers to the gap between the myelin sheath segments. These nodes are crucial for the rapid transmission of electric signals along an axon. The myelin sheath is a lipid-based insulating layer covering the axons, similar to insulation on electrical wires. However, unlike wire insulation, the myelin sheath has periodic gaps known as nodes of Ranvier, which allow for the 'jumping' of action potentials or nerve impulses. This process of jumping from one node to the next is called saltatory conduction and enables faster signal transmission compared to an unmyelinated axon.
The axon membrane at these nodes contains voltage-gated potassium and sodium channels, which play a critical role in the regeneration of the action potential as it moves along the axon. Additionally, the distances between these gaps are referred to as axon segments, which are insulated by myelin produced by glial cells, such as Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system.