What is the difference between CNS myelin and PNS myelin?
Myelin is present in the central nervous system (CNS) and peripheral nervous system (PNS); however only the central nervous system is affected by MS. CNS myelin is produced by special cells called oligodendrocytes. PNS myelin is produced by Schwann cells. The two types of myelin are chemically different,...
What is myelin and why is it important in MS?
Like the coating around an electrical wire, myelin insulates and protects the axon and helps speed nerve transmission. Myelin is present in the central nervous system (CNS) and peripheral nervous system (PNS); however only the central nervous system is affected by MS. CNS myelin is produced by special cells called oligodendrocytes.
How is myelin formed in the peripheral nervous system?
Peripheral nervous system (PNS) myelin is formed by the differentiation of the plasma membrane of Schwann cells. One of the biochemical characteristics that distinguishes myelin from other biological membranes is its high lipid-to-protein ratio.
What is the function of myelin sheath in peripheral nervous system?
Peripheral nervous system (PNS) myelin is formed by the differentiation of the plasma membrane of Schwann cells … By imposing saltatory conduction on the nervous impulse, the principal role of the myelin sheath is to allow the faster propagation of action potentials along the axons which it surrounds.
What is responsible for myelination in the PNS?
PNS myelin is produced by Schwann cells. The two types of myelin are chemically different, but they both perform the same function — to promote efficient transmission of a nerve impulse along the axon.
Which cells make myelin in the PNS?
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.
Which cells are involved with myelination?
Myelin is formed in the central nervous system (CNS; brain, spinal cord and optic nerve) by glial cells called oligodendrocytes and in the peripheral nervous system (PNS) by glial cells called Schwann cells. In the CNS, axons carry electrical signals from one nerve cell body to another.
What are responsible for myelination?
In the central nervous system (CNS), oligodendroglial cells are responsible for the synthesis and maintenance of myelin, whereas Schwann cells subserve this role in the peripheral nervous system (PNS).
How is myelin formed in the PNS?
Myelin is formed in the PNS (peripheral nervous system) and CNS by the innermost sheet-like glial process in contact with the axon spiraling around it and spinning out multiple layers of overlapping membrane. Cytoplasm becomes expelled from all but the innermost and outermost layers of the myelin sheath.
What cells are in the PNS?
The peripheral nervous system (PNS) consists of the nerves and ganglia outside of the brain and spinal cord. There are four major types of glia in the PNS. They are myelinating and non-myelinating Schwann cells, satellite glial cells (SGCs), enteric glial cells (EGCs), and olfactory ensheathing cells (OECs).
Are responsible for myelination quizlet?
Schwann cells are the myelination cells of the peripheral nervous system, and thus (d) is the correct answer.
What are Schwann cells responsible for?
The Schwann cell plays a vital role in maintaining the peripheral nervous system (PNS). Schwann cells are derived from neural crest cells, and come in two types either myelinating or non-myelinating Schwann cells. Both play a pivotal role in the maintenance and regeneration of axons of the neurons in the PNS.
Are Schwann cells myelin?
Myelinating Schwann cells are radially and longitudinally polarized cells (Salzer 2003; Ozcelik et al. 2010; Pereira et al. 2012). With myelination, Schwann cells organize into distinct membrane domains, each with a unique array of proteins, and a communicating set of cytoplasmic compartments (Fig.
What is myelination quizlet?
myelination is the process in which. -part of an axon is wrapped in a myelin sheath. myelination. the process by which axons become coated with myelin, a fatty substance that speeds the transmission of nerve impulses from neuron to neuron.
Where does myelination occur?
Myelination begins in utero, when a fetus is about 16 weeks of age and continues into adulthood. During the tween years, myelination is particularly occurring in the frontal lobe of the brain. 2 Myelination in this area is important for tweens' cognitive development.
Are Schwann cells myelin?
Schwann cells (SCs) are the main glial cells of the peripheral nervous system which wrap around axons of motor and sensory neurons to form the myelin sheath.
What makes up 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.
Do oligodendrocytes produce myelin?
Oligodendrocytes are the myelinating cells of the central nervous system (CNS). They are the end product of a cell lineage which has to undergo a complex and precisely timed program of proliferation, migration, differentiation, and myelination to finally produce the insulating sheath of axons.
Which structures make up the PNS?
The peripheral nervous system refers to parts of the nervous system outside the brain and spinal cord. It includes the cranial nerves, spinal nerves and their roots and branches, peripheral nerves, and neuromuscular junctions.
Where is myelin produced?
Myelin is present in the central nervous system (CNS) and peripheral nervous system (PNS); however only the central nervous system is affected by MS. CNS myelin is produced by special cells called oligodendrocytes. PNS myelin is produced by Schwann cells.
How does the body heal myelin?
Scientists have discovered that the body heals some lesions naturally by stimulating oligodendrocytes in the area — or by recruiting young oligodendrocytes from further away — to begin making new myelin at the damaged site.
What causes inflammation in the central nervous system?
In MS, an abnormal immune system response produces inflammation in the central nervous system. This process: 1 Damages/destroys myelin and oligodendrocytes 2 Causes damage to the underlying nerve fiber 3 Produces damaged areas (lesions or scars) along the nerve, which can be detected on magnetic resonance imaging (MRI) 4 Slows or halts nerve conduction – producing the neurologic signs and symptoms of MS
What is the axon wrapped in?
Most of the axons in the central nervous system are wrapped in myelin, a substance rich in lipids (fatty substances) and proteins. Like the coating around an electrical wire, myelin insulates and protects the axon and helps speed nerve transmission.
What is the immune system response to MS?
Abnormal immune reaction believed to attack myelin. In MS, an abnormal immune system response produces inflammation in the central nervous system. This process: Damages/destroys myelin and oligodendrocytes. Causes damage to the underlying nerve fiber.
What are the structures in the nervous system that allow us to think, see, hear, speak, feel, eliminate,?
Neurons are the structures in the nervous system that allow us to think, see, hear, speak, feel, eliminate (bowel/bladder) and move. Each neuron is made up of a cell body and an axon (the extension of the cell body that carries messages).
Is myelin repair slow?
However, this natural repair process is slow and incomplete. Scientists are investigating several different strategies for stimulating the repair of myelin, including testing existing drugs, finding ways to stimulate oligodendrocytes to produce myelin, and ways to protect oligodendrocytes and myelin from further damage.
What distinguishes myelin from other membranes?
One of the biochemical characteristics that distinguishes myelin from other biological membranes is its high lipid-to-protein ratio. All the major lipid classes are represented in the myelin membrane, while several myelin-specific proteins have been identified.
What is the role of myelin sheath?
By imposing saltatory conduction on the nervous impulse, the principal role of the myelin sheath is to allow the faster propagation of action potentials along the axons which it surrounds. Peripheral nervous system (PNS) myelin is formed by the differentiation of the plasma membrane of Schwann cells.