Question

In the process of beginning an action potential, the threshold refers to:

neuron extensions that conduct messages toward the cell body. a minimum intensity of excitatory minus inhibitory stimulation. neuron extensions that send messages to other neurons. the junction between a sending and receiving neuron.

Answer 1

The threshold in the process of starting an action potential is the level that the membrane potential must reach for the neuron to become active. It is an all-or-none process that, once initiated by reaching the threshold, cannot be stopped until it reaches its conclusion.

Step-by-step explanation:

In the process of beginning an action potential, the threshold refers to a minimum intensity of excitatory minus inhibitory stimulation. The threshold is the critical level to which the membrane potential must depolarize in order to initiate an action potential. When a neuron receives signals, small pores on the neuronal membrane open, allowing Na+ ions to enter the cell. When the internal charge of the cell becomes more positive and reaches the threshold of excitation, the neuron becomes active and the action potential begins. This process is an all-or-none phenomenon, similar to a light switch being turned on; once the threshold is reached, there is no turning off an action potential until it completes its course all the way down the axon to the terminal buttons.

Action potentials operate on this all-or-none principle, similar to sending a text message that cannot be stopped once sent. If the threshold is reached due to sufficient excitatory inputs, an action potential will fire and propagate down the neuron's axon, leading eventually to the release of neurotransmitters at synaptic junctions with other neurons. This electrochemical event is essential for neural communication and is the basis for processing information in the nervous system.

Answer 2

Option (3).

Step-by-step explanation:

The action potential may be defined as the change in the electric potential of the cell that helps in the propagation of the nerve impulse. The resting membrane potential of the cell is -70mV.

Threshold potential may be defined as the minimum potential required to transmit the nerve impulse. If the difference between the excitatory signal and inhibitory signal exceeds the minimum intensity, known as threshold. The propagation of nerve impulse occurs.

Thus, the correct answer is option (3).