Chapter 3 Notes
Neurons: cells in the nervous system that communicate with one another to
perform information-processing tasks.
Cell body: the part of a neuron that coordinates information-processing tasks
and keeps the cell alive.
dendrite: the part of neuron that receives information from other neurons and
relays it to the cell body.
axon: the part of a neuron that transmits information to other neurons,
muscles, or glands.
myelin sheath: an insulating(隔絕) layer of fatty material.
glial cells: support cells found in the nervous system.
In many neurons, the axon is covered by a myelin sheath, the myelin sheath
is composed of glial cells.
Synapse: the junction or region between the axon of one neuron and the
dendrites or cell body of another.
sensory neurons: neurons that receive information from the external world
and convey this information to the brain via the spinal cord.
motor neurons: neurons that carry signals from the spinal cord to the muscles
to produce movement.
interneurons: neurons that connect sensory neurons, motor neurons, or other
resting potential: the difference in electric charge between the inside and
outside of a neuron’s cell membrane.
The communication of information within and between neurons proceeds in
two stages: conduction and transmission.
action potential: an electric signal that is conducted along a neuron’s axon to
a synapse. (electric impulse)
refractory period: the time following an action potential during which a new
action potential cannot be initiated.
terminal buttons: knoblike structures that branch out from an axon.
Cocaine stop re-uptake many dopamine, norepinephrine flowing around,
resulting in increased activation of their receptors. Therefore they are strong
agonists.(so does amphetamine)
agonists: drugs that increase that action of a neurotransmitter.
Antagonist: drugs that block the function of a neurotransmitter.
Prozac(drug used to treat depression) blocks the reuptake of the
neurotransmitter serotonin, making it part of category of drugs called selective
serotonin reuptake inhibitors.
propranolol (antagonist) of class of drugs called beta-blockers that obstruct a
receptor site for norepinephrine in the heart(主治心絞痛) action potential: sodium channels in the axon membrane open and potassium
channels close, Na+ ions to flow inside the axon.
resting potential: after maximum, sodium channels close and potassium
channels open, allowing k+ to flow out of the axon.
nervous system: an interacting network of neurons that conveys
electrochemical information throughout the body.
central nervous system (CNS): the part of the nervous system that is
composed of the brain and spinal cord.
peripheral nervous system (PNS): the part of the nervous system that
connects the central nervous system to the body’s organs and muscle.
somatic nervous system: set of nerves that conveys information into and out
of the central nervous system.
autonomic nervous system: a set of nerves that carries involuntary and
automatic commands that control blood vessels, body organs, and glands. It
has to major subdivisions, the sympathetic(set of nerves that prepares the
body for action in threatening situations) nervous system and the
parasympathetic(helps the body return to a normal resting state) nervous
spinal reflexes: simple pathways in the nervous system that rapidly generate
hindbrain: an area of the brain that coordinates information coming into and
out of the spinal cord.
medulla: an extension of the spinal cord into the skull that coordinates heart
rate, circulation, and respiration. inside the medulla is a small cluster of
neurons called the reticular formation, regulates sleep, wakefulness, and
levels of arousal.
cerebellum: (behind the medulla) a large structure of the hindbrain that
controls fine motor skills.
pons: (major are of the hindbrain)a structure that relays information from the
cerebellum to the rest of the brain.