TEMPORAL LOBES Center for hearing;
Wernicke’s areain left temporal lobe plays role in
understanding language and making meaningful sentences;
Right temporal lobe important for understanding music/tonality;
Sound from both ears processed mostly contralaterally;
Smell processed near front of temporal lobes.
Although specific regions of the brain are associated with specific functions, if one
region is damaged, the brain can reorganize to take over its function, which is called plasticity.Structure and Function of the Neuron
Your extraordinarily complex brain is composed of trillions of neurons and glial cells. Glial
cellsguide the growth of developing neurons, help provide nutrition for and get rid of
wastes of neurons, and form an insulating sheath around neurons that speeds conduction.
The neuron is the basic unit of structure and function of your nervous system. Neurons
perform three major functions: receive information, process it, and transmit it to the rest
of your body. Three major regions of a neuron enable the cell to communicate with other
cells (see Figure 7.3). The cell body(a.k.a. cyton or soma) contains cytoplasm and the
nucleus, which directs synthesis of such substances as neurotransmitters. The dendritesare
branching tubular processes capable of receiving information. The axonemerges from the
cyton as a single conducting fiber (longer than a dendrite) which branches and ends in tips
calledterminal buttons, axon terminals, or synaptic knobs. The axon is usually covered by
an insulating myelin sheath(formed by glial cells).
Neurotransmittersare chemicals stored in structures of the terminal buttons called
synaptic vesicles. Different neurotransmitters have different chemical structures and per-
form different functions. For example, acetylcholine (ACh)causes contraction of skeletal
muscles, helps regulate heart muscles, is involved in memory, and also transmits messages70 ❯ STEP 4. Review the Knowledge You Need to Score High
Motor
cortexFigure 7.2 Regions of the left cerebral cortex in lateral view.