Table of Contents
Which description best describes myelin?
Myelin is a fatty substance that wraps around nerve fibers and serves to increase the speed of electrical communication between neurons.
What is the waxy substance that covers the neuron fibers?
Most axons are covered by a white, waxy substance called myelin. This coating insulates nerves and increases the speed at which impulses travel. Myelin is created by Schwann cells in the peripheral nervous system and oligodendrocytes in the CNS. There are small gaps in the myelin coating, called nodes of Ranvier.
Which one of the following describes how the interior surface of a cell membrane of a depolarized neuron differs from the external environment?
Which one of the following describes how the interior surface of a cell membrane of a depolarized neuron differs from? sodium ions is higher on the outside of its membrane and potassium is higher on the inside E. sodium and potassium ions are in equal concentrations on the inside and outside of the membrane Page 5 23.
What cells form the myelin sheaths around the axons in CN II and VIII?
Oligodendrocytes (or oligodendroglia) are star-shaped neuroglia that form the myelin sheaths on axons of the central nervous system. A single oligodendrocyte has about 15 flat, broad, arm-like processes coming out of the cell body.
What is myelin and the myelin sheath?
Myelin is an insulating layer, or sheath that forms around nerves, including those in the brain and spinal cord. It is made up of protein and fatty substances. This myelin sheath allows electrical impulses to transmit quickly and efficiently along the nerve cells.
Why is it called white matter?
The white matter is so-called because it contains many nerve fibers or neurons that are sheathed in the white fatty insulating protein called myelin. In section, myelin is white whereas the gray matter is that color due to all the gray nuclei contained in the cells that make it up.
Do Schwann cells produce myelin?
Schwann cells make myelin in the peripheral nervous system (PNS: nerves) and oligodendrocytes in the central nervous system (CNS: brain and spinal cord). Myelinated axons are ensheathed along their entire length.
What are myelin sheaths formed by?
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).