Question

1.Neurons receive stimulation causing local potentials until they reach the threshold.

2.Sodium (Na) ions diffuse inward, changing the electric charge of the membrane, depolarizing it.
3.Sodium channels in the trigger zone of the axon open.
4.Potassium channels in the membrane open.
5.When the signal reaches the end of the axon, the synaptic knob releases a neurotransmitter (a chemical messenger) which takes the signal to the next neuron, muscle cell, or gland.
6.The resulting action potential causes a wave of exchanging of ions down the membrane which causes an electric current to travel down the axon.
7.Potassium (K) ions diffuse outward, repolarizing the membrane.

Answer 1

Neurons have charged membranes due to different ion concentrations inside and outside. An action potential is fired when at least the threshold of excitation is reached. Neurotransmitters transmit the action potential at synapses through binding to postsynaptic receptors.

Step-by-step explanation:

Neurons have charged membranes because there are different concentrations of ions inside and outside of the cell. Voltage-gated ion channels control the movement of ions into and out of a neuron. When a neuronal membrane is depolarized to at least the threshold of excitation, an action potential is fired. The action potential is then propagated along a myelinated axon to the axon terminals. In a chemical synapse, the action potential causes release of neurotransmitter molecules into the synaptic cleft. Through binding to postsynaptic receptors, the neurotransmitter can cause excitatory or inhibitory postsynaptic potentials by depolarizing or hyperpolarizing, respectively, the postsynaptic membrane. In electrical synapses, the action potential is directly communicated to the postsynaptic cell through gap junctions—large channel