the cells that surround an axon creating a myelin sheath in the pns are called schwann cells.
the cells that surround an axon creating a myelin sheath in the pns are called schwann cells.
the cells that surround an axon creating a myelin sheath in the pns are called?
schwann cells
myelin is a lipid-rich (fatty) substance formed in the central nervous system (cns) by glial cells called oligodendrocytes, and in the peripheral nervous system (pns) by schwann cells. myelin insulates nerve cell axons to increase the speed at which information (encoded as an electrical signal) travels from one nerve cell body to another (as in the cns) or, for example, from a nerve cell body to a muscle (as in the pns). the myelinated axon can be likened to an electrical wire (the axon) with insulating material (myelin) around it. however, unlike the plastic covering on an electrical wire, myelin does not form a single long sheath over the entire length of the axon. rather, each myelin sheath insulates the axon over a single section and, in general, each axon comprises multiple long myelinated sections separated from each other by short gaps called nodes of ranvier. each myelin sheath is formed by the concentric wrapping of an oligodendrocyte or schwann cell process around the axon.
myelin
in terms of total mass, myelin comprises approximately 40% water; the dry mass comprises between 60% and 75% lipid and between 15% and 25% protein. protein content includes myelin basic protein (mbp), which is abundant in the cns where it plays a critical, non-redundant role in formation of compact myelin; myelin oligodendrocyte glycoprotein (mog), which is specific to the cns; and proteolipid protein (plp,) which is the most abundant protein in cns myelin, but only a minor component of pns myelin. in the pns, myelin protein zero (mpz or p0) has a similar role to that of plp in the cns in that it is involved in holding together the multiple concentric layers of glial cell membrane that constitute the myelin sheath. the primary lipid of myelin is a glycolipid called galactocerebroside. the intertwining hydrocarbon chains of sphingomyelin strengthen the myelin sheath. cholesterol, is an essential lipid component of myelin, without which myelin fails to form.
myelin