Psychology2016

46 CHAPTER 2

Neurons and Nerves: Building the Network

This chapter will explore a complex system of cells, chemicals, and organs that work together

to produce behavior, thoughts, and actions. The first part of this complex arrangement is the

nervous system, a network of cells that carries information to and from all parts of the body.

The field of neuroscience is a branch of the life sciences that deals with the structure and

functioning of the brain and the neurons, nerves, and nervous tissue that form the nervous

system. Biological psychology, or behavioral neuroscience, is the branch of neuroscience

that focuses on the biological bases of psychological processes, behavior, and learning, and it

is the primary area associated with the biological perspective in psychology.

STRUCTURE OF THE NEURON: THE NERVOUS SYSTEM’S BUILDING BLOCK

2.1 Identify the parts of a neuron and the function of each.

In 1887, Santiago Ramón y Cajal, a doctor studying slides of brain tissue, first theorized that the

nervous system was made up of individual cells (Ramón y Cajal, translation, 1995). Although

the entire body is composed of cells, each type of cell has a special purpose and function and,

therefore, a special structure. For example, skin cells are flat, but muscle cells are long and

stretchy. Most cells have three things in common: a nucleus, a cell body, and a cell membrane

holding it all together. The neuron is the specialized cell in the nervous system that receives

and sends messages within that system. Neurons are one of the messengers of the body, and

that means that they have a very special structure, which we will explore in the Figure 2. 1.

nervous system
an extensive network of specialized
cells that carries information to and
from all parts of the body.

neuroscience
a branch of the life sciences that deals
with the structure and function of
neurons, nerves, and nervous tissue.

biological psychology or
behavioral neuroscience
branch of neuroscience that focuses on
the biological bases of psychological
processes, behavior, and learning.

neuron
the basic cell that makes up the
nervous system and that receives and
sends messages within that system.

dendrites
branchlike structures of a neuron that
receive messages from other neurons.

soma
the cell body of the neuron responsible
for maintaining the life of the cell.

axon
tubelike structure of neuron that
carries the neural message from the
cell body to the axon terminals, for
communication with other cells.

The parts of the neuron that receive messages from other cells are called the

dendrites. The name dendrite means “tree-like,” or “branch,” and this structure does

indeed look like the branches of a tree. The dendrites are attached to the cell body, or

soma, which is the part of the cell that contains the nucleus and keeps the entire cell alive

and functioning. The word soma means “body.” The axon (from the Greek for “axis”) is a

fiber attached to the soma, and its job is to carry messages out to other cells. The end of

Figure 2.1 The Structure of the Neuron

CC

Synapse

Soma (Cell body)

Dendrite Action potential

Axon terminals

Nucleus

Axon

Node

Myelin sheath

Neuron