P1-ANES SAS 4 PAIN PATHWAY

carry message from one part of the body to another

Function of a nerve

Impulses

These messages in the form of electrical action potentials are called

THreshold potential/ Firing threshold

When the falling electrical potential reaches a critical level, an extremely rapid phase of depolarization results. this is termed?

Resting potential

This is a negative electrical potential of -70mV that exists across the nerve membrane, what's it called?

Differing concentrations of ions

Resting potential is produced by?

1. Contration of electrolytes interior of the nerve cell

2. Permiability of nerve membrane to sodium and potassium

In electrochemistry of nerve conduction, the events depend on two important factors:

-slightly permeable to sodium ions

-freely permeable to potassium ions

-freely permeable to chloride ions

In the resting state, the nerve membrane would be?

-increase in permeability of cell membrane to sodium ions

in depolarization, the excitement of a nerve segment leads to what?

widening of trasnmembrane ion channels

How is permeability of cell membrane accomplished?

rapid influx of sodium ions to the interior of the nerve cell

what causes depolarizatio of the nerve membrane from its resting level

Firing threshold

This is the magnitude of the decrease in negative transmembrane potential that is required to initiate an action potential (impulse)

decrease in negative transmembrane potential of 15mV

In the firing threshold, what type of situation does it need to reach it?

TRue, it has to be 15mV or more

TRue or false: less than 15mv will not initate an impluse

True

True or false: in a normal nerve, the firing threshold remains constant

A. reversed

at the end of depolarization, the electrical potential of the nerve is actually?

A. reversed

B. irreversible

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0.3msec

how much time does the depolarization require?

repolarization of the membrane

When is the action potential terminated

Unmyelinated nerves

The spread of an impulse in an unmyelinated nerve fiber is characterized as a relative slow forward-creeping process

Myelinated nerves

impulse conduction in myelinated nerve fiber occurs by means of current leaps from node to node- a process termed Saltatory conduction

To leap

what does saltare mean in latin verb?