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Which part of the neuron can propagate an action potential?
axon
When a stimulus is sufficiently great enough to change the membrane potential and propagate an action potential it is called?
recruitement
What are the conducting cells that can produce and propagate an action potential for communication throughtout the body?
neurons
Where is action potential specifically found?
Action potentials are found on muscular or neural cells. The propagate along the cells's membrane surface.
What is the membrane of a nerve cell is comprised of?
Its main function is to propagate the action potential (the 'impulse') along the length of the axon.
Is it true that an action potential is basically an electrical current?
I would say yes, but it is much more complex then that. The action potential is caused by a ion gradient, between the inner and out cell. This gradient is used to propagate an impulse.
How does the nervous stimulus pass to the motor end plate?
An activated neuron will send an action potential from upper motor neurons to lower motor neurons to effector organs. It is able to propagate the action potential to the motor end plate by release of neurotransmitters, chiefly acetylcholine. On the terminal bouton the action potential opens voltage gated calcium channels. There is an influx of calcium in the pre-synaptic cell and it pushes the vesicles that contain acetylcholine. These vesicles will pass through the synaptic cleft and bind to cholinergic receptors on the post synaptic neuron. Each vesicle has a miniature end plate potential of 0.5mV. In a normal action potential, it will depolarize the post synaptic motor neuron from -85mV to approximately 0-15mV. So that's approximately 180 vesicles.* The influx of neurotransmitters (primarily acetylcholine) will depolarize the motor end plate and propagate the action potential. *Threshold of an action potential is approximately -55mV so technically the minimum required to continue an action potential is around 60 vesicles.
What is the effect of tetrodotoxin?
Tetrodotoxin blocks action potentials by binding with the voltage-gated, fast sodium (Na+) channels in neural membranes. This prevents the influx of sodium ions required to propagate an action potential.
What structure in the neuron helps to speed up the transmission of the action potential?
To speed up transmission of the action potential from where it originates (axon hillock) to where it ends (axon terminal), the action potential propagates by 'saltatory conduction' - and the structure that makes this possible is the insulating layer of myelin sheath that wraps around the axon, arranged in 'nodes' along its length. Technically, it's the gaps between the nodes (nodes of Ranvier) that cause the action to continually propagate and maintain its fast conduction velocity.
How does the myelin sheath affect the speed of action potential?
Myelin sheath does several things that affect the speed of an action potential.It acts as an insulator around a neuron axon, thereby focusing the propagation of the action potential along the axis of the axon.The action potential "leaps" from one node of Ranvier (the node in between two myelinated segments) to the next, and to the next, and to the next, and so on, faster than the action potential can propagate as a wave along an unmyelinated axon of the same diameter.The regions along a myelinated axon depolarize locally and successively, thus allowing an action potential to travel along an axon using less energy, which in turn allows the neuron to repolarize more quickly, and thus be ready to conduct the next action potential sooner, thereby increasing the overall speed of information transmission.
Which cell must have action potentials to produce one or more action potentials in the postsynaptic cell?
A neuron (nerve cell) receives dendritic input in order to generate action potentials to transmit signals of the same. After the action potential triggers release of neurotransmitters in the axonal terminal of that neuron, those neurotransmitters propagate the signal forward to the next neuron, and so forth.
What was the effect of curare on eliciting an action potential?
It creates an action potential
