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In myelinated cells, nodes of Ranvier increase conduction velocity via saltatory conduction. These nodes are sites of high capacitance and low resistance. What is the role of nodes of Ranvier in increasing conduction velocity?

1) They increase the resistance in the myelinated cells
2) They decrease the capacitance in the myelinated cells
3) They increase the capacitance in the myelinated cells
4) They decrease the resistance in the myelinated cells

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Final answer:

The nodes of Ranvier decrease resistance in myelinated cells, allowing for rapid regeneration of action potentials and faster neural communication through saltatory conduction.

Step-by-step explanation:

The nodes of Ranvier play a crucial role in increasing conduction velocity in myelinated cells. They facilitate this by allowing for saltatory conduction, where the action potential 'jumps' from one node to the next rather than propagating continuously along the entire length of the axon. This process is much faster because of the myelin sheath's insulating properties, which prevent ion leakage and signal loss. The nodes are locations with high capacitance and low resistance, which allows for efficient signal transmission.

Answering the original question, the correct statement is:

  1. They decrease the resistance in the myelinated cells.

By having lower resistance at the nodes, action potentials are rapidly regenerated through the influx of Na+ ions, enabling quicker impulse transmission. Thus, saltatory conduction through these strategically placed nodes significantly increases the speed of neural communication without the need for continuous Na+ and K+ channels along the entire axon, saving the neuron energy.

User Radin Gospodinov
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