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Why does the myelin sheath have gaps in it?
Because the sheath is produced by several Schwann cells that arrange themselves end to end along the nerve fiber, each Schwann cell forms only one part of the tiny segment of the sheath.
Which cell process are not myelinated?
According to McGraw Hill (please see related link below): Many nerve fibers in the CNS and PNS are unmyelinated. In the PNS, however, even the unmyelinated fibers are enveloped in Schwann cells. In this case, one Schwann cell harbors from 1 -12 small nerve fibers in grooves in its surface. The Schwann cell's plasma membrane does not spiral repeatedly around the fiber as it does in a myelin sheath, but folds once around each fiber and somewhat overlaps itself along the edges. This wrapping is the neurilemma (also called a mesaxon in unmyelinated nerve fibers). Also, gray matter of the brain and dendrites are unmyelinated, while axons are myelinated.
Do all nerve cells have a neurilemma?
The neurilemma is the Schwann cell. This helps with regeneration of cells. The nerve cells in the brain do not have neurilemma and therefore, cannot regenerate.
Which of the following PNS neuroglia help to form myelin sheaths around larger nerve fibers in the PNS?
Schwann Cell
Is myelination of the nerve fibers in the periphreal nervous system the job of the schwann cell?
Yes, in the CNS it is oligodendrocytes that myelinate axons.
What is the neurilemma and what is it function?
the plasma membrane surrounding a Schwann cell of a myelinated nerve fiber and separating layers of myelin
Why does the myelin sheath have gaps in it?
Because the sheath is produced by several Schwann cells that arrange themselves end to end along the nerve fiber, each Schwann cell forms only one part of the tiny segment of the sheath.
What is a schwann cell?
A schwann cell are supporting cells of the peripheral nervous system, they wrap themselves around nerve axons.
Funtion of the nucleus of a schwann cell?
When the peripheral nervous system develops, Schwann cells line up along unmyelinated axons at regular intervals that eventually become the nodes of Ranvier (important for saltatory nerve condution). The ensheathing process takes place as Schwann cells wrap around the axon many times over, creating concentric layers whose cytoplasm progressively condenses. Contact with the axons also activates myelin genes leading to the expression of myelin glycoproteins and lipids across the Schwann cell plasma membrane. The sheath therefore consists of plasma membrane, cytosol, lipids, glycoproteins, and the Schwann cell nucleus.*So basically, the schwann cells is a protective membrane that covers the axon. It also produces myelin sheath (the coating of a neuron), which increases the speed of the nerve impulse.
Which best describes the components of a nerve?
axons, blood vessels, connective tissue, Schwann cell.
Which bestdescribes thecomponents ofa nerve?
axons, blood vessels, connective tissue, Schwann cell.
What are nerves and muscle fibers?
A nerve fiber is a threadlike extension of a nerve cell and consists of an axon andmyelin sheath (if present) in the nervous system. There are nerve fibers in the central nervous system and peripheral nervous system. A nerve fiber may be myelinated and/or unmyelinated. In the central nervous system (CNS), myelin is produced byoligodendroglia cells. Schwann cells form myelin in the peripheral nervous system (PNS). Schwann cells can also make a thin covering for an axon which does not consist of myelin (in the PNS). A peripheral nerve fiber consists of an axon, myelin sheath, Schwann cells and its endoneurium. There are no endoneurium and Schwann cells in the central nervous system. A myocyte (also known as a muscle cell or muscle fiber) [1] is the type of cell found inmuscle tissue. They are long, tubular cells that arise developmentally from myoblasts to form muscles in a process known as myogenesis. [2] There are various specialized forms of myocytes: cardiac, skeletal, and smooth muscle cells, with various properties. Cardiac myocytes are responsible for generating the electrical impulses that control the heart rate, among other things
Which cell process are not myelinated?
According to McGraw Hill (please see related link below): Many nerve fibers in the CNS and PNS are unmyelinated. In the PNS, however, even the unmyelinated fibers are enveloped in Schwann cells. In this case, one Schwann cell harbors from 1 -12 small nerve fibers in grooves in its surface. The Schwann cell's plasma membrane does not spiral repeatedly around the fiber as it does in a myelin sheath, but folds once around each fiber and somewhat overlaps itself along the edges. This wrapping is the neurilemma (also called a mesaxon in unmyelinated nerve fibers). Also, gray matter of the brain and dendrites are unmyelinated, while axons are myelinated.
Do all nerve cells have a neurilemma?
The neurilemma is the Schwann cell. This helps with regeneration of cells. The nerve cells in the brain do not have neurilemma and therefore, cannot regenerate.
Muscle cell are stimulated by nerve fiber called a?
[Edit]
What is a long nerve fiber that carries impulses from one nerve cell to the next called?
an axon
Which of the following PNS neuroglia help to form myelin sheaths around larger nerve fibers in the PNS?
Schwann Cell
