Chapter 2 Summary - Chapter 2 Summary The nervous system is...

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Chapter 2 Summary The nervous system is made up of a complex network of cells throughout your body. Since psychology is the study of behavior and mental processes, understanding how the nervous system works provides fundamental information about what is going on inside your body when you engage in a specific behavior, feel a particular emotion, or have an abstract thought. The field of study that deals with these types of questions is called neuroscience . The role of the nervous system is to carry information. Without your nervous system, you would not be able to think, feel, or act. The cells in the nervous system that carry information are called neurons . Information enters a neuron at the dendrites , flows through the cell body (or soma ) and down the axon in order to pass the information on to the next cell. Although, neurons are the cells that carry the information, most of the nervous system consists of glial cells . Glial cells provide food, support, and insulation to the neuron cells. The insulation around the neuron is called myelin and works in a way very similar to the plastic coating of an electrical wire. Bundles of myelin-coated axons are wrapped together in cable like structures called nerves . Neurons use an electrical signal to send information from one end of its cell to the other. At rest, a neuron has a negative charge inside and a positive charge outside. When a signal arrives, gates in the cell wall next to the signal open and the positive charge moves inside. The positive charge inside the cell causes the next set of gates to open and those positive charges move inside. In this way, the electrical signal makes its way down the length of the cell. The movement of the electrical signal is called an action potential . After the action potential is over, the positive charges get pumped back out of the cell and the neuron returns to its negatively charged state. This condition is called the resting potential . A neuron acts in an all-or-none manner. This means the neuron either has an action potential or it does not. The neuron indicates the strength of the signal by how many action potentials are produced or “fired” within a certain amount of time. Neurons pass information on to target cells using a chemical signal. When the electrical signal travels down the axon and reaches the other end of the neuron called the axon terminal , it enters the very tip of the terminal called the synaptic knob and causes the neurotransmitters in the synaptic vesicles to be released into the fluid-filled space between the two cells. This fluid-filled space is called the synapse or the synaptic gap . The neurotransmitters are the chemical signals the neuron uses to communicate with its target cell. The neurotransmitters fit into the receptor sites of the target cell and create a new electrical signal that then can be transmitted down the length of the target cell. Neurotransmitters can have two different effects on the target cell.
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Chapter 2 Summary - Chapter 2 Summary The nervous system is...

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