Examples of freewheeling in a Sentence. 1  She led a freewheeling life in the city. 2  James Bond has long been the model of the freewheeling hero who encounters danger and excitement in every corner of the globe.
Myelin Function. By Sally Robertson, BSc. The myelin sheath is a protective covering that surrounds fibres called axons, the long thin projections that extend from the main body of a nerve cell or neuron. This sheath is composed of protein and lipids.he main function of myelin is to protect and insulate these axons and enhance their transmission of electrical impulses. If myelin is damaged, the transmission of these impulses is slowed down, which is seen in severe neurological conditions such as multiple sclerosis.
The myelin sheath is a greatly extended and modified plasma membrane wrapped around the nerve axon in a spiral fashion [ 1 ]. The myelin membranes originate from and are a part of the Schwann cells in the peripheral nervous system (PNS) and the oligodendroglial cells in the central nervous system (CNS) (see Chap. 1).Each myelin-generating cell furnishes myelin for only one segment of any given axon.wo adjacent segments of myelin on one axon are separated by a node of Ranvier. In this region, the axon is not covered by myelin. At the paranodal region and the Schmidt-Lantermann clefts, the cytoplasmic surfaces of myelin are not compacted and Schwann or glial cell cytoplasm is included within the sheath.