Describe an action potential

Answer 1

Firstly, a stimulus causes an influx of sodium ions into the axon. This causes further sodium voltage-gated ion channels to open, causing more sodium ions to move into the axon, down an electrochemical gradient, this depolarises the axon, if the influx of sodium ions reaches the threshold value of the axon then an action potential is produced. The sodium-voltage gated channels close when the potential of the axon reaches +40 mv. Potassium ion channels open, allowing K+ ions out of the axon and into surrounding tissue fluid. The electrical gradient is reversed and more potassium ions leave the axon. This is repolarisation. As more potassium ion channels are open compared to at resting potential, hyperpolarisation occurs. This is where the axon is more negative then usual. The sodium-potassium pump actively transports 3 Na+ ions out of the axon and 2K+ ions into the axon, with the use of ATP; allowing the resting potential to be reastablished.

Answer 2

It conveys a neural impulse along an axon.

It does so in a manner that is as strong at the end of the axon as at the beginning.

It only fires when enough input impulses sum up at the axon hillock (the beginning of the axon), and it does not vary in strength, so it's considered an 'all or nothing' signal; different intensities of sensory inputs are conveyed by different rates of firings, such that a strong sensory input will yield a fast series of action potentials, and a weak sensory input will yield just a few action potentials.

Answer 3

An action potential is a rapid change in electrical potential across the cell membrane of a neuron, which allows for communication between neurons. It is initiated by a depolarization of the cell membrane, followed by a spike in electrical activity as ions flow in and out of the cell. This wave of depolarization and repolarization allows for the transmission of signals along the neuron.

Answer 4

descibe the action potential the characteristics and the direction