What is a neuron? Describe the three parts of a neuron and their functions. Explain the process of how a neural message is transmitted from the end of one neuron to the beginning of another and the process by which a neuron moves from a resting state (resting potential) to firing (action potential) and then back to a resting state.

A neuron is a specialized cell in the nervous system that is responsible for transmitting information through electrical and chemical signals. Neurons are the basic building blocks of the nervous system and play a crucial role in processing and transmitting information throughout the body.

The three main parts of a neuron are the dendrites, the cell body (soma), and the axon. The dendrites are the receiving end of the neuron and are responsible for receiving signals from other neurons. The cell body contains the nucleus and other organelles necessary for the neuron's function. The axon is the long, slender projection of the neuron that transmits signals to other neurons or to muscles or glands.

The process of transmitting a neural message from the end of one neuron to the beginning of another is called synaptic transmission. When an action potential reaches the end of an axon, it triggers the release of neurotransmitters into the synapse, the small gap between the end of one neuron and the dendrites of another. These neurotransmitters then bind to receptors on the receiving neuron, causing a new action potential to be generated and the signal to be transmitted.

The process by which a neuron moves from a resting state (resting potential) to firing (action potential) and then back to a resting state is known as the action potential. When a neuron is at rest, it maintains a negative charge inside the cell compared to the outside. When a stimulus is received, the cell membrane becomes permeable to sodium ions, causing an influx of positive charge and depolarization. This depolarization triggers the opening of voltage-gated sodium channels, leading to a rapid influx of sodium ions and the generation of an action potential. After the action potential has been transmitted, the cell repolarizes by closing the sodium channels and opening potassium channels, allowing potassium ions to leave the cell and restore the negative charge. This returns the neuron to its resting state, ready to transmit another signal.