from neuron to brain 4th edition pdf download

The arrangement is analogous to the branching of a tree, which increases its reception of sunlight by increasing its total leaf surface area. Dendrites and their branches greatly increase a neuron's surface area, and this increases the number of messages that the neuron can receive and the number of sources from which they can come. The length and branching patterns of the dendrites vary from one type of neuron to another.

The neuron gets its distinctive appearance from its dendrites and axon, elongated processes that emanate from the cell body.

The diameter of the cell body of a vertebrate animal is about 10–100 µm (the largest would be roughly the size of the period at the end of this sentence). A final section summarizes the problems arising from the nature of neurobiology that must be addressed when a substance is tested for neurotoxicity, the subject of Chapter 4.Ī neuron ( Figure 2-1) has a more or less round cell body (soma), which contains its nucleus and organelles for protein synthesis. The fourth section describes examples of neurotoxicant-induced damage of several types. The next section discusses several aspects of the nervous system that make it especially vulnerable to chemically induced damage. The first two sections of this chapter summarize our current understanding of the nervous system. Observation of the response of experimentally exposed animals or inadvertently exposed humans to neurotoxic chemicals advances our understanding of neurobiology while generating information about the consequences of exposure to environmental pollutants. The ultimate goal of neuroscience is to understand how this system functions normally and how subtle perturbations can lead to disease and dysfunction. Our abilities to act, to feel, to learn, and to remember all depend on the complex anatomic arrangements and proper integrative functioning of the nervous system, of which we have only a rudimentary understanding. Conversely, abnormal functioning in other systems can modify neurologic functioning. Thus, neurologic dysfunction has a major impact that goes beyond the nervous system itself. The nervous system also integrates the functions of the various organ systems. Other systems, such as the circulatory and reproductive systems, provide information to the nervous system, which in turn controls their functioning.

Virtually all physiologic functions are influenced or controlled by the nervous system. In addition to coordinating functions that are commonly associated with the brain, such as thinking, the nervous system plays a major role in physiologic regulation. The nervous system is the communication and information-storage system of the body.

From neuron to brain 4th edition pdf download