An orthodromic impulse runs along an axon in its anterograde direction, away from the soma. In the heart, orthodromic may also refer to an impulse going in the correct direction from the dendrites to axon terminal (from the atria to the ventricles) in contrast to some impulses in re-entry.
What is orthodromic action potential?
Orthodromic action potentials evoked by synaptic excitation displayed similar changes in amplitude and shape. These observations lead to the conclusion that the soma, initial segment and neighbouring nodes of Ranvier contribute significantly to the shape of the action potential.
What is antidromic axon reflex?
An antidromic impulse in an axon refers to conduction opposite of the normal (orthodromic) direction. That is, it refers to conduction along the axon away from the axon terminal(s) and towards the soma.
How is an antidromic action potential possible?
Electrical stimulation of the central nervous system creates both orthodromically propagating action potentials, by stimulation of local cells and passing axons, and antidromically propagating action potentials, by stimulation of presynaptic axons and terminals.
What is orthodromic and antidromic conduction?
In an orthodromic study, the recording electrodes measure the action potential traveling in the physiologic direction. In an antidromic study, the recording electrodes measure the action potential traveling opposite the physiologic direction.
Is WPW antidromic vs orthodromic?
Types of arrhythmias in WPW are AVRT (80%). There are two type of AVRT, orthodromic (90 to 95%) vs. antidromic (5%), other types are atrial fibrillation (AF) (10% to 30%), atrial flutter, and ventricular tachycardia/ventricular fibrillation [4-7]. The different types of arrhythmias are shown in Figure 5.
What is Chronaxie and Rheobase?
Rheobase—The minimum current required to depolarize a nerve given an infinite duration of stimulation. Chronaxie—The duration of current required to depolarize a nerve to threshold when the current is two times the rheobase.
What is antidromic tachycardia?
Antidromic AVRT is a wide QRS complex (fully preexcited) tachycardia. In the presence of atrial tachycardia, atrial flutter, AF, or AVNRT, the QRS complexes can also be preexcited when the AP acts as a bystander and is not a critical part of the reentry circuit.
What is the advantages of antidromic sensory recording?
The major advantage of the antidromic approach reflects the recording site (the recording electrodes are on the digit). Because the tissue between the nerve fibers and the recording electrodes is minimal at this site, the amplitude of the response is much greater.
What are the 3 major components of a reflex arc?
The simplest arrangement of a reflex arc consists of the receptor, an interneuron (or adjustor), and an effector; together, these units form a functional group. Sensory cells carry input from the receptor (afferent impulses) to a central interneuron, which makes contact with a motor neuron.
What are Polysynaptic reflexes?
Any reflex with more than one synapse (1), not counting the synapse between neuron and muscle, and hence involving one or more interneurons. In humans, all reflexes except stretch reflexes are polysynaptic. Compare monosynaptic reflex. [ From Greek polys many + neuron a nerve]
How is H reflex measured?
The H-reflex test is performed using an electric stimulator, which gives usually a square-wave current of short duration and small amplitude (higher stimulations might involve alpha fibers, causing an F-wave, compromising the results), and an EMG set, to record the muscle response.
Where in a neuron does Saltatory conduction take place?
SCs and Establishment of the Nodes of Ranvier
Nodes of Ranvier are at the core of saltatory conduction along myelinated axons (Fig. 1(d)). They contain all of the molecular machinery responsible for the propagation of action potentials along myelinated nerves (Black et al., 1990).
What is a synapse?
Synapses refer to the points of contact between neurons where information is passed from one neuron to the next. Synapses most often form between axons and dendrites, and consist of a presynaptic neuron, synaptic cleft, and a postsynaptic neuron.
What is compound action potential amplitude?
The amplitude of the recorded compound action potential is a summation of the individual action potentials from the different axons. When the waves pass the recording site in phase they add constructively and display a higher peak.
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