nervous system, a collection of hundreds of billions of specialized and interconnected cells through which messages are sent between the brain and the rest of the body. The nervous system consists of the central nervous system (CNS), made up of the brain and the spinal cord, and the peripheral nervous system (PNS), the neurons that link the CNS to our skin, muscles, and glands. And we will see that our behavior is also influenced in large part by the endocrine system, the chemical regulator of the body that consists of glands that secrete hormones. A neuron is a cell in the nervous system whose function it is to receive and transmit information soma, which contains the nucleus of the cell and keeps the cell alive dendrite, which collects information from other cells and sends the information to the soma
axon- which transmits information away from the cell body toward other neurons or to the muscles and glands.. axon is very fast—it can happen up to 1,000 times each second
myelin sheath is a layer of fatty tissue surrounding the axon of a neuron that both acts as an insulator and allows faster transmission of the electrical signal.
resting potential, a state in which the interior of the neuron contains a greater number of negatively charged ions than does the area outside the cell.
change in electrical charge that occurs in a neuron when a nerve impulse is transmitted is known as the action potential.
breaks between the sausage-like segments of the myelin sheath. Each of these gaps is a node of Ranvier
synapses- areas where the terminal buttons at the end of the axon of one neuron nearly, but don’t quite touch the dendrites of another.
neurotransmitter is a chemical that relays signals across the synapses between neurons.
reuptake, a process in which neurotransmitters that are in the synapse are reabsorbed into the transmitting terminal button ready to again be released after the neuron fires.
agonist is a drug that has chemical properties similar to a particular neurotransmitter and thus mimics the effects of the neurotransmitter.
antagonist is a drug that reduces or stops the normal effects of a neurotransmitter.
TABLE 3.1 The Major Neurotransmitters and Their Functions
Neurotransmitter Description and function Notes
A common neurotransmitter used
in the spinal cord and motor
neurons to stimulate muscle
contractions. It’s also used in the
brain to regulate memory,
sleeping, and dreaming.
Alzheimer’s disease is associated with an undersupply of
acetylcholine. Nicotine is an agonist that acts like
Dopamine Involved in movement,
motivation, and emotion,
Dopamine produces feelings of
pleasure when released by the
brain’s reward system, and it’s also
involved in learning.
Schizophrenia is linked to increases in dopamine,
whereas Parkinson’s disease is linked to reductions in
dopamine (and dopamine agonists may be used to treat
Endorphins Released in response to behaviors
such as vigorous exercise, orgasm,
and eating spicy foods.
Endorphins are natural pain relievers. They are related to
the compounds found in drugs such as opium,
morphine, and heroin. The release of endorphins creates
the runner’s high that is experienced after intense
The major inhibitory
neurotransmitter in the brain.
A lack of GABA can lead to involuntary motor actions,
including tremors and seizures. Alcohol stimulates the
release of GABA, which inhibits the nervous system and
makes us feel drunk. Low levels of GABA can produce
anxiety, and GABA agonists (tranquilizers) are used to
Glutamate The most common
neurotransmitter, it’s released in
more than 90% of the brain’s
synapses. Glutamate is found in
the food additive MSG
Excess glutamate can cause overstimulation, migraines
Serotonin Involved in...