CHAPTER 4 NOTES
The human brain is the only object capable of studying itself.
The Brain and its Components
The brain consists of anywhere between 10 billion and 100 billion nerve cells. The nerve
cells of the brain are indeed organized in modules-clusters of nerve cells that communicate
with each other. Modules are also connected to each other.
Structure of the Nervous System
The brain has three major functions: controlling behaviour, processing and retaining the
information we receive from the environment, and regulating the body’s physiological
The nervous system consists of two divisions. The brain and the spinal cord make up the
central nervous system. The spinal cord is a long, thin collection of nerve cells attached to
the base of the brain and running the length of the spinal column. The spinal cord contains
circuits or nerve cells that control some simple reflexes, such as automatically pulling away
from a painfully hot object. The central nervous system communicates with the rest of the
body through nerves – bundles of fibres that transmit information in and out of the central
nervous system. The peripheral nervous system contains the cranial and spinal nerves.
Information from the head and neck region reaches the brain through the cranial nerves.
Sensory information from the rest of the body reaches the spinal cord through the spinal
The human brain has three major parts: the brain stem, the cerebellum, and the cerebral
The brain stem is one of the most primitive regions of the brain, and its functions are
correspondingly basic ones: primarily control of physiological functions and automatic
The pair of the cerebral hemispheres constitutes the largest part of the human brain. The
cerebral hemispheres contain the parts of the brain that evolved most recently-and thus are
involved in behaviours of particular interest to psychologists.
The cerebellum, attached to the back of the brain stem, looks like a miniature version of the
cerebral hemispheres. Its primary function is to control and coordinate movements.
Meninges are the three layered set of membranes that enclose the brain and spinal cord.