Which cells produce insulating myelin?

Which cells produce insulating myelin?

Myelin is made by two different types of support cells. In the central nervous system (CNS) — the brain and spinal cord — cells called oligodendrocytes wrap their branch-like extensions around axons to create a myelin sheath. In the nerves outside of the spinal cord, Schwann cells produce myelin.

What lipid is myelin made of?

In addition to cerebroside, the major lipids of myelin are cholesterol and ethanolamine-containing plasmalogens (see Chap. 3). Lecithin is also a major myelin constituent, and sphingomyelin is a relatively minor one.

What produces myelin?

Schwann cells make myelin in the peripheral nervous system (PNS: nerves) and oligodendrocytes in the central nervous system (CNS: brain and spinal cord). In the PNS, one Schwann cell forms a single myelin sheath (Figure 1A).

What are the components of the myelin sheath?

Myelin is composed of about 40% water and the dry mass is composed of about 80% lipids and 20% protein. The mainly lipid composition of the myelin gives it a white hue, hence the reference to the brain’s “white matter.” The main lipid found in myelin is a glycolipid called galactocerebroside.

How is myelin produced?

Myelin is formed by Schwann cells in the peripheral nervous system (PNS) and oligodendrocytes in the central nervous system (CNS). Each Schwann cell forms a single myelin sheath around an axon. In contrast, each oligodendrocyte forms multiple sheaths (up to 30 or more) around different axons (Figure 1).

Why is myelin an insulator?

Myelin Promotes Rapid Impulse Transmission Along Axons In unmyelinated axons, the action potential travels continuously along the axons. Myelin is rich in lipids (approximately 80%) and can therefore act as an insulator (meaning high transverse resistance and a low electrical capacitance) along the internodal segments.

Where are glycolipids produced?

the Golgi apparatus
The glycolipid is assembled in the Golgi apparatus and embedded in the surface of a vesicle which is then transported to the cell membrane. The vesicle merges with the cell membrane so that the glycolipid can be presented on the cell’s outside surface.

What are derived lipids?

Derived lipids: fatty acids that can originate from the simple and compound lipids by means of hydrolysis. Cholesterol, bile acids, and sex and adrenocortical hormones are examples. Lipids can and do occur in cells in the form of droplets or bound to other tissue entities.

Is myelin a lipid?

Myelin is the protective lipid sheath wrapped around a nerve. It functions as an insulator, akin to the protective coating on a wire, speeding up electrical transmission of signals along a neuron. Myelin also plays a role in maintaining the health of neurons.

How is myelin sheath formed in PNS?

Myelin is formed by Schwann cells in the peripheral nervous system (PNS) and oligodendrocytes in the central nervous system (CNS). Each Schwann cell forms a single myelin sheath around an axon. Myelin itself forms by the spiral wrapping around an axon of an enormously expanded glial plasma membrane that then compacts.