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What refers to the constiction or gaps that occurs between the Schwann cells that are for impulse conduction in myelinated fibers?
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∙ 9y ago
Nodes of Ranvier
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∙ 9y ago
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How does myelination affect nerve conduction velocity?
Myelination will speed the nerve conduction velocity considerably. Myelin is found in Schwann cells which encircle a given axon. It acts mainly as an insulator so that depolarization in one cell does not set off depolarizations in adjoining cells. When a neural membrane is depolarized, local currents are set up between positive and negative ions causing membrane conduction. In myelinated fibers, the local currents go from one internode (or node of Ranvier) in between two Schwann cells to the next internode. Thus we have "salutatory conduction" where a neural impulse actually jumps from one internode to the next without being conducted down the entire cell membrane.
Along myelinated sections between nodes in a myelinated axon electrical signals are conducted by?
saltatorial conduction
What is the relationship between the degree of myelination and and conduction velocity?
That myelinated axons fare faster, unmyelinated are slower.
How does myelination effect nerve conduction?
Myelination will speed the nerve conduction velocity considerably. Myelin is found in Schwann cells which encircle a given axon. It acts mainly as an insulator so that depolarization in one cell does not set off depolarizations in adjoining cells. When a neural membrane is depolarized, local currents are set up between positive and negative ions causing membrane conduction. In myelinated fibers, the local currents go from one internode (or node of Ranvier) in between two Schwann cells to the next internode. Thus we have "salutatory conduction" where a neural impulse actually jumps from one internode to the next without being conducted down the entire cell membrane.
What is the relationship between size of nerve and conduction velocity?
For unmyelinated nerves there is a relationship between axon diameter and conduction velocity. Larger diameter nerves conduct faster. For myelinated nerves the a larger diameter nerve will conduct faster between the nodes of ranvier where the action potential is propagated. Conduction is said to be saltatoryas it jumps from node to node.
How does temperature on a physiological way effect nerve conduction?
Myelination will speed the nerve conduction velocity considerably. Myelin is found in Schwann cells which encircle a given axon. It acts mainly as an insulator so that depolarization in one cell does not set off depolarizations in adjoining cells. When a neural membrane is depolarized, local currents are set up between positive and negative ions causing membrane conduction. In myelinated fibers, the local currents go from one internode (or node of Ranvier) in between two Schwann cells to the next internode. Thus we have "salutatory conduction" where a neural impulse actually jumps from one internode to the next without being conducted down the entire cell membrane.
What is the relationship between nerve size and conduction velocity?
velocity proportional to square root of diameter
How do you create myelenated neurons?
You don't, but glial cells, (oligodendrocytes in the CNS, and Schwann cells in the PNS), wrapped one after another around the axons of neurons with gaps between them called the nodes of Ravnier do create myelinated neurons.
How does conduction differ on myelinated vs unmyelinated axons?
Very simples, myelinated axons have a myelin sheath! These are produced by the schwann cells in the Peripheral Nervous System and oligodendrocytes in the Central Nervous System. The myelin sheath is made out of lipids (fats) and proteins. The benefits of a myelinated axons is a faster transmission of an electrical impulse and also insulation. The breakdown of a myelin sheath from a medical background results in Demyelination.Tortora, G, Derrickson, B (2009) Principles of Anatomy and Physiology, Wiley, Asia, 12th Edition, Volume 1, Pages 416-423Hope this helps!
What is the difference between myelinated and unmyelinated nerves?
structurally they are very similar with the only real difference being that the myelinated (M) nerve (neurone) has schwann cells on its axon surface, but functionally they are very different as the M transmitts nerve impulses alot faster than the non-myelinated(NM) as it has nodes ranvier that allow the impulse to jump from gap to gap between schwann cells and so sppeding the rate at which it can depolarise the membrane to allow transmittion of the impulse, i could go on alot more but i wont :) hope this helps yours scincerly a uni student trying to look smart ;) i got to OXFORD (brookes) ...
Is saltatory conduction faster than conduction on an unmyelinated fiber?
wherever the Schwann cells wrap around the axon, the sodium and potassium ions cannot cross the membrane; the Schwann cells wrap too tightly around the axonal membrane for there to be any extracellular space underneath them. Therefore, the only place that an action potential can occur is at the node of Ranvier-- the space between the Schwann cells. Because of this, the action potential seems to jump from node to node along the axon. "Jumping" is what the word "saltatory" means.
What is the difference between an internode and node of ranvier?
A Node of Ranvier is the space between two myelinated segments on an axon, while an internode is the space between two Nodes of Ranvier (alternativenly, the myelinated segment).
